MadModder

The Craftmans Shop => New from Old => Topic started by: awemawson on November 07, 2015, 10:57:55 AM

Title: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 10:57:55 AM
Many years ago - (probably 9 or so) I bought a 2 ton Thwaites articulated swivel tip dumper powered by an electric start two cylinder Petter 'PH2'. I got it as we planned to move to a place where I needed to break up and shift over an acre of concrete  :bugeye:

Well that move fell through, however it came in very handy at my current place. One cylinder was always a bit reluctant to fire up until warm but I 'got by' for all those years.

Truth be told shortly after I got it, I exchanged injectors between the cylinders to no avail, and checked that both were squirting mist, but I was inhibited from further investigation as not only was time very limited, but so was access to the engine. The seat frame arrangement spans the top of the engine, and as well as the seat it also holds the air filter, the hand brake lever and the tipping hydraulic control. Just unbolting it wasn't an easy option, so it got ignored  :clap:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: John Rudd on November 07, 2015, 11:03:02 AM
Is that you driving in the first picture? :)
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:08:47 AM
Now this machine has done some serious shifting for me, but it's been getting progressively worse over the years. I managed to convince myself that the front cylinder must be low compression. So much so that when I was at a 'close out' sale of a plant hire place and I saw that they had some PH2 barrels and pistons I moved them from their shelf to mine for future repairs. Well those barrels have sat on my shelf for five years  :bang:

As most of my heavy building work is now done and time a bit freer I thought I'd have a crack at the dumper. First issue was that as it's an electric start with no way to hand crank it, I couldn't easily prove the low compression theory. The main crank shaft is 1.5" with a 3/8" key way, and on the hand cranked versions there is a special handle that has a trip dog that engages with this keyway.

Trouble is that handle wont fit through the hole in the back plate of this digger , also it costs £44  :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:10:00 AM
Is that you driving in the first picture? :)

Oh yes - and that's my youngest daughter - whose now turned 30 and is married with two girls and another on the way  :bugeye: :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:14:42 AM
Now I don't need to crank start it, it has a starter motor, but I do need to turn it over in a controlled fashion to check the valves and compression, so I welded up a rough and ready handle.

I did start to broach a keyway in that collar with the Bridgeport slotting head, but my 3/8"slotting tool wasn't long enough, so I came up with a 'bodge' key comprising three 3/8" slugs of mild steel welded into suitably placed holes.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:22:32 AM
So at least now I could manually turn the engine over, and darn me the compression 'seemed' good on both cylinders. Now I do have a petrol engine compression tester but it only goes up to 300 psi, so not a lot of good for a diesel engine.

Then I thought, if I open the exhaust valves on each cylinder in turn, crank the engine over on the starter with only one cylinder compressing, then surely measuring the current taken by the starter should give a rough comparison of the effort required and hence the compression.

The following readings are:

A/ Both cylinders decompressed (presumably least effort)

B/ Front cylinder compressing rear not

C/ Rear cylinder compressing, front not
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:26:37 AM
  :scratch: :scratch: Now how odd is that  :scratch: :scratch:

It is drawing MORE current when cranking WITHOUT compressing than when the valves are closed - I can't explain that - it may be that the engine turns over faster, but it didn't seem to.

However the comparison between cylinders showed that they weren't miles off each other, but I do find those readings EXTREMELY odd  :coffee:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:39:59 AM
So I decided that probably we have an injection timing or volume issue. The pumped volume to the 'faulty' cylinder seemed less than the other, but it's a rather subjective judgement.

All the timing and volume settings are on the right hand side of the engine at a low level, with access totally blocked by the diesel tank. But before that the seat base had to come off. The air filter and hydraulic control weren't too bad, but the hand brake lever and cable were silly! The adjustment screws into a plate that was welded on under the seat mount, and without stripping the cable out all the way from the front axle (via the articulation pivot) it wouldn't rotate to unscrew. At this point I decided that it was a stupid design, and cut through the welds with an angle grinder and will re-engineer it when the time comes to put it back together. :bang:

The tank is used as a structural element supporting various horizontal bits of chequer plate so the left hand 'mudguard' (6 mm plate) and a cill plate (more 6 mm plate) had to come off before the tank fixings were accessible.

(Pictures are slightly in the wrong order)
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:43:31 AM
So now at last at least I can see where all the twiddly bits are without standing on my head and using a mirror  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:52:19 AM
There is an injector pump for each cylinder, and their 'volume racks' are linked to move in synchronism to give equal volume to each. There is a governor in the bowels of the engine that moves the racks against a spring which at rest presses the rack end against an 'overload stop'.

The setting up requires that the racks are first synchronised so that a calibration mark on each is 13/16" from the spot face on the pumps - this is set by adjusting the length of the link rod that joins them. However this setting needs to be 'at rest' when the rack is limited by the 'overload stop'

Problem is the overload stop is hideously worn and flopping all over the place
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:55:11 AM
It is basically a little hinge, one part fixed to the end of one rack, and the other when folded down carries an adjustable bolt that presses against the 'overload bracket'. The hinge is a clevis and tenon, both of which were very worn

(This 'hinge' is folded up when cold starting)
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 11:58:34 AM
Now the clevis part is available for £27 but not the other bit, but why buy when you can make?

I decided that there was enough 'meat' left in the old clevis to open the slot up to 6 mm, re-bore it's pivot hole (also now 6 mm), but to make an entirely new 'tenon' to suit the new size of the slot.

All then I needed to make was an over size pivot pin (6 mm x 18 mm) - I also reproduced the 'wiring hole' that lets the adjusting bolt be wired to the flappy bit of the hinge to stop it vibrating loose. I just LOVE drilling 1.5 mm holes 1/2" deep - not !!!!
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 07, 2015, 12:20:26 PM
So when the rain stops I need to delve further into the engine - there are two covers, one below each injector pump, that (should !!) reveal the adjustment that sets the timing of the injection for each pump.

Essentially there is an adjuster that sets how high the pump plunger sits on it's cam follower. By removing the output valve on each pump and setting the fly wheel to the correct point for injection, the adjuster can be tweaked to 'just' stop fuel flowing (gravity from tank) - apparently this is called 'spill timing' and is common on these sorts of engines.

But first I've got to master and sort out all the levers and fixings that are mounted on the rear cover
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: appletree on November 07, 2015, 01:26:40 PM
Until my dad died 22 years ago we had a plant hire family firm which we started in 1972, we had lots of Dumpers, Pumps, concrete mixers with Petter singles and twins, Lister singles twins triples and 4s. I was going to tell you about the setup on PH series engines. As I thought iíll tell him XYZ I further read the post and what I was going to say was in front of me. Invariably there is a strong cylinder regarding starting, seems a bit odd as nothing obvious is standing out yet.
 
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: DavidA on November 08, 2015, 05:49:50 AM
You could make up a simplified version of the differential compression tester.

Remove the injectors.  Make an adapter that will allow you to connect an air line to the cylinders (one at a time) then, with the piston held at top dead centre, pressurise the cylinder.

You can then listen for any air leaks from the inlet and exhaust ports. Also listen for the sound of air getting into the crankcase past the pistons.

Just a thought.

Dave.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: appletree on November 08, 2015, 07:02:19 AM
There is an injector pump for each cylinder, and their 'volume racks' are linked to move in synchronism to give equal volume to each. There is a governor in the bowls of the engine that moves the racks against a spring which at rest presses the rack end against an 'overload stop'.

The setting up requires that the racks are first synchronised so that a calibration mark on each is 13/16" from the spot face on the pumps - this is set by adjusting the length of the link rod that joins them. However this setting needs to be 'at rest' when the rack is limited by the 'overload stop'

Problem is the overload stop is hideously worn and flopping all over the place
Perhaps not immediately obvious to our readers the overload stop is disengaged for starting, it then drops back into place once the engine is running and the governor takes over.
The purpose of the device is to prevent over injection when the engine is under large/excessive load thus preventing over fuelling .
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Manxmodder on November 08, 2015, 09:57:31 AM
  :scratch: :scratch: Now how odd is that  :scratch: :scratch:

It is drawing MORE current when cranking WITHOUT compressing than when the valves are closed - I can't explain that - it may be that the engine turns over faster, but it didn't seem to.

However the comparison between cylinders showed that they weren't miles off each other, but I do find those readings EXTREMELY odd  :coffee:

Andrew, what I believe you may be witnessing here is an atmosperic engine braking type of thing.

Decompressor engine brakes,usually only seen on 2 strokes, work on the principle that the piston has to work hard to draw air in through a small orrifice under only atmospheric pressure hence creating a partial vacuum in the cylinder.

On the subject of testing the cylinders for compression,why not make up a simple compression tester that replaces the injector with a suitable pressure range gauge fitted.
......OZ.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: RussellT on November 08, 2015, 12:45:04 PM
If you want a comparative reading rather than an absolute figure you could use your petrol engine compression tester.  If you used an extension pipe between the tester and the cylinder you would increase the unswept volume and decrease the pressure reading to a suitable amount.

I'm following with interest. :thumbup:

Russell
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 08, 2015, 01:23:45 PM
Thanks chaps but at this stage I think that the compression issue is a red herring. Given fine weather tomorrow I hope to go through the setting up procedure for the injection timing and metering.

Visitors today, but I did manage to make up a 'swan neck', that screws onto the output of the pump being set up, and acts as a 'stand pipe' to let you observe the 'spill cut off point' more accurately as you tweak the cam follower tappet adjuster.

The piston of the injector pump rises, and at one point covers the 'spill port' at which time the pressure starts to build and fuel is injected. The piston has an angled cut in it that, as it is rotated by the rack alters the effective point at which cut off occurs and hence changes the volume squashed though the injector. So it is important to set the rest point of the rack first, and that depends on that little brass 'overload stop' I re-made the other day.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 09, 2015, 07:53:55 AM
Well not the best day in my life  :bang: :bang:

It all started quite nicely. I went through the procedure carefully to set the rack synchronisation and then went on to the  injection timing using the 'spill' method. I started by cleaning up the marks on the fly wheel - it carries TDC marks for both cylinders (as they are 180 degrees apart) and also for 24 degrees and 28 degrees before TDC as it seems 24 is for engines running up to 1650 rpm and 28 degrees for engines running up to 2200 rpm. No plate on mine so I decided to use the 24 degree setting.

Starting with #1 cylinder I removed the injection pumps one way valve as instructed, and installed the 'Swan Neck' slackened off the adjuster as per the book, set the timing mark bang on and then raised the tappet screw until the flow stopped - all went apparently as it should. I took the precaution of taking a picture before and after to be able to compare.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 09, 2015, 08:08:47 AM
As you can see it took about two turns to set it at the spill point, which was a very definite setting - I went past and approached it again several times to get it 'spot on' and I can see why they suggest the use of the swan neck rather than just letting it spill over the top of the fitting. It slows to a series of drips which then can be tweaked to no drip.

I then put the one way valve back in the pump, reconnected the injector pipe, and thought it wise at this point to prime fuel though. Stupidly I just flicked the starter motor to spin the engine and there was an almighty BANG and bits flew in all directions   :bugeye:

Looking at the poor old pump it had disintegrated - blowing itself off it's mounting flange. At this stage I don't know if perhaps the one way valve mis-seated and it hydraulically destroyed itself. Or if perhaps having raised the tappet two turns the pump piston contacted the top of it's cylinder and mechanically broke it. I'll certainly need to find out before another pump goes on :scratch:

I have to say that as I was doing the 'rack synchronisation' settings earlier I'd thought that the whole pump / rack set up was rather worn and sloppy, so perhaps this is a blessing in disguise.

Anyway I've dug deep into my pockets and ordered up a pair of injector pumps, so play is suspended until they arrive (so are most other activities like food and drink as they were not cheap  :bang:)
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: RotarySMP on November 09, 2015, 08:37:21 AM
Well illustrated report thanks Andrew. Shame that the injector pump has left us. Maybe it is the sort of building site machinery which really prefers never to get maintenance :)

Mark
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Manxmodder on November 09, 2015, 10:46:24 AM
I guess that if it's mechanical destruction and the plunger piston has made contact with something then there will be some marks internally to evidence that.

Does your flywheel bear two sets of timing marks? On some of the Petters I,ve seen in the past there is a  second set of marks duplicated on the other side of TDC.

These other timing marks are for a counter rotating engine build spec......OZ.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 09, 2015, 11:52:40 AM
I think most Petter flywheel have the marks on each side of TDC as depending how they are assembled they can run clockwise or anticlockwise (with the right internals) No real witness marks evident showing mechanical contact. The body of the pumps are cast aluminium so they've been replaced before probably. I think Petter had later bits made in India.

Spent the afternoon drawing up gaskets in Autocad for the side covers. Could have tapped them out but access isn't ideal and the Laser Cutter makes such a neat job of things - far better than scissors or knife  :clap:

(Did I say  -  I LOVE my laser cutter  :ddb: )
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: petertheterrible on November 09, 2015, 12:48:19 PM
Excelent post.  Only things I would like to add, watch out for 'over spilling'.

Only thing the PH manual does not state is, in setting spill timing before tightening the follower setting screw is to turn engine by hand, preferably not with the crank but just the flywheel.  (Stated in manuals like that of the SR strangely) 

Each pump must be checked for 'overspill', if not you will destroy the pump on the PH. (Experience gained the costly way)  (On some other models bending the camshaft).

Slight 'overspill' will cause the pump head to rise (inside pump self) causing diesel in the crankcase.

The most likely thing when these twins and threes aren't performing equal on all cylinders is dirt in the pump and injector.
Dirt causes the pump to spill differently as the piston is obstructed and when the injector is also dirty, incorrect injection isn't detected by eye.

Personally I just pull the injectors an test them.  A lot can be determined by just testing injectors which are usually easy to locate and remove.  These engines perform nearly with no compression and always amazes me how easy they start compared to something like a Wolseley.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: petertheterrible on November 09, 2015, 01:00:23 PM
The PH that you have can be timed to run in either direction, inlet becomes exhaust and your off. 
New timing marks will be made and a new ID plate fitted indicating R.

If it says Petter it comes from England.  AVA's come from India.  Same thing, same quality sort off  (internal paint peels/ lack the khaki appeal), different name.
 
Not to  :wack:  :hammer: your parade but the only broken pump bodies I have ever seen are due to human error and not the pumps, sorry.

One thing to look out for is that the right hand side bold attaching the pump also secures the priming lever and that these pumps are also shim-set where correct spill diesel quantity isn't reached.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 09, 2015, 02:11:57 PM
Peter, yes I'm sure I'm the culprit in this case - just trying to work out how  :scratch:

I've decided that when I fit the new pump I'll do the spill setting, then slacken the bolts holding the pump down and gently turn things over by hand pressing the pump onto it's mounting. If anything is fouling it'll rise up safely.

I believe that the AVA engines have a very slightly smaller bore with the same stoke, but the big ends are also a bit smaller.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 09, 2015, 03:55:40 PM
To set the fuel rack position accurately there are two special tools illustrated in the book of words, and having done it this morning without them, I now appreciate why a special tool is recommended.

The rack slides horizontally in bushes in the pump body, and these bushes are pressed into a hole around which the casting is 'spot faced'. The rack itself has a calibration mark, and the critical setting is measured from the spot face to this calibration mark. For the 'maximum fuel setting'  it needs to be 1/2" and with the overload stop in place it needs to be 13/16".

It's possible to do it with a digital vernier, but very fiddly and a bit subjective, as the measurement has to 'hook round' the bushes and the rubber bellows, so I thought I'd try and make a combination gauge with both measurements incorporated, roughly copying the illustration in the book.

(The actual measurement is from the end of the 'point' facing downwards to the under side of the horizontal pointer.)
 
Cut it on the Laser Engraver - it's only polycarbonate, but I'm hopefully not going to be using it very often  :ddb:

(Did I say - I LOVE my laser engraver  :lol: )
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Manxmodder on November 09, 2015, 06:43:08 PM
It's about time someone developed a process for case hardening polycarbonate  :) .....OZ.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 10, 2015, 09:09:37 AM
These little beauties arrived at lunch time, so I'll have to pluck up courage and fit them.

 :bang: :bang: The only conclusion I can come to is I must have timed them on the wrong TDC mark on the flywheel   :bang: :bang:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 11, 2015, 07:16:48 AM
  :ddb: Well I'm delighted to say that she's now running on both cylinders - first time in years  :ddb:

VERY carefully checked which TDC mark corresponded to which cylinder, then sprayed them different colours 'just in case' - only had sheep marker sprays so they will eventually bio-degrade !

Fitted the pumps one by one, but when I came to set up the fuel rack positions discovered that the new pumps had no calibration marks on the racks :bang: Waiting for the supplier to give me a reasonable explanation why they are not there, he's 'checking with his diesel man' . So I had to do it a bit hit and miss, which is annoying as the 'spill point' entirely depends on the initial setting of the rack to set the injection timing accurately. Anyway she's running, and I can probably do a bit of itterative tweaking to get it a bit closer than it is currently.

To celebrate I've decided to give her a reconditioned set of injectors as these ones are not perfect. I took them out today to clean them, then thought - 'hang it, replace them'

Only got to put the mechanics back together, change the air, diesel and oil filters having given her an oil change. Oh and chip the concrete off the top of the gear box so I can get at the oil filler, sort the centre articulation pivot that is VERY sloppy, and then sort out the brake master cylinder - press the pedal and the brake come on and stay on, and can only be released by bleeding at the master cylinder outlet.

Might even take a sledge hammer to the 'body work' and take out a few dents  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on November 11, 2015, 07:35:33 AM
Good stuff!!
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: John Rudd on November 11, 2015, 09:04:21 AM
   


Might even take a sledge hammer to the 'body work' and take out a few dents  :lol:

A bit of spannering and body building too.....! Is there no end to your talents?  :bow:

Well Done Andrew....good you got it sorted.. :clap:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: petertheterrible on November 11, 2015, 12:37:52 PM
Timing with either the left or right timing marks won't lead to a breakage of the pump.  The only way to screw up something by timing alone on one of these is to change the timing on the gears, which would lead to bent valves.  (Wrong marks used = won't start)

Are the pumps you got new or re-conned?  Most re-conned parts usually don't have a lot of markings of any type.  Have a disassembled pump needing to be rebuild, if it is fine with you I can post pick in a couple weeks time.

Best pump set tool, better than a piece of saw blade, is to cut the tail of a cheap vernier or use one of these plastic card, material, salesman verniers and altering the mouth to look like the beak of a bird that flew into a windscreen. Small inside leg calipers also work when you have adequate access.

You broke the pump by setting the stroke of the follower so far that it crushed the piston of the pump, ie stroke of pump was exceeded by stroke region of follower, and the only thing that could give was the pump body. 

I had engines in the past, other models, where the spill was set to far either bending the cam/ breaking cam bush housings/ breaking gears on the timing train, not on PH models though, so you are extremely lucky.

Slackening the pump won't tell you anything as the pump is spring laden and will rise.  After setting spill the pump is left alone and the engine while decompressed is turned slowly by hand, preferably without a crank to attain if the bump stop is exceeded.

On Rustons, small one's, the follower is of the plunger type with set screw that bends with excessive force, pump bodies can be cast iron.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: petertheterrible on November 11, 2015, 12:40:50 PM
Actually don't feel bad about breaking the pump, you are definitely not the first that broke the ears off.  Incorrect setting of diesel pumps off all kinds has lead to the death of many a engine and many a smile on the engine builders mugs. :)
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 11, 2015, 01:03:25 PM
No I'm sure the problem was I set the pump spill point using the wrong cylinders TDC mark - as all references were to start with cylinder nearest the fly wheel I had assumed that that was #1. It's not ! The cylinders are 180 out from each other, so when I set the spill at 24 degrees before TDC I was actually more on the heel of the cam than the rising edge, so as it rotated, as you say the injection pump piston ran out of room.

It's a pity that the pump I destroyed was the better of the two, but never mind both were pretty ropey - lots of slack in the rack bushes, and the rack itself was noticeably worn.

The good news is in searching for an air filter element it turns out to be identical to the one I used in my JCB 3CX that I sold a couple of years ago, but still had spares on the shelf  :thumbup:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 11, 2015, 03:11:51 PM
Did a quick fix to the rain cap for the air filter housing this afternoon. The rain cap had rusted / vibrated off years ago and was just sitting there by gravity. So I rolled up a 2" tube from some 1.5 mm galvanised sheet, cut some tabs into it, bent them out as mounting ears and bolted it all together. The 2" tube slips as a tight fit over the inlet which points upwards in use. Rolled up sheet was spot welded to form the tube which I rolled using a set of rollers I inherited from my friend George years back. Doesn't get used often but by heck they are useful at times.

I still need to sort the 'pop valve' that is just a little rubber moulding that sits on the spigot at the lower end of that picture - just a length of 40 mm soft rubber tube would do. The idea is that the suck of incoming air closes this valve, but any back fire has an easy route to escape and also dust collects on it and engine pressure variations expel it. No sign of a spare anywhere so I may well resort to the soft rubber tube if I can find any - maybe even a bit of old cycle inner tube if the bore is about right.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: RussellT on November 11, 2015, 04:38:51 PM
Well done Andrew. :clap:

I do admire the way you overcome difficulties that would have others scrapping the machines.

   sort out the brake master cylinder - press the pedal and the brake come on and stay on, and can only be released by bleeding at the master cylinder outlet.

I had a similar problem with a car brake recently - it turned out to be a flexible hose which would only permit fluid to flow at high pressure.  It doesn't sound like that's the case on your dumper but I suspect a similar mechanism.

Russell



Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 11, 2015, 04:47:34 PM
Thanks Russell.

Not had the master cylinder off yet - it may well not be original as it had obviously just been changed when I got the dumper years back so sourcing the rubber bits might be a chore.

Good news on the 'pop valve' (or dust valve, or vacuator or drain valve depending whose describing it) It looks as though one from a Massey Ferguson 165 tractor may fit with a bit of trimming to the flange on the filter housing  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Pete W. on November 12, 2015, 10:20:23 AM
Hi there, Andrew,

I'm pleased you're making good progress.

If the Ferguson tractor valve doesn't work out, try your local Dive shop!  It sounds as though the exhaust valve from the original Siebe-Gorman (or Cousteau-Gagnan) Aqualung demand valve might do the job. 
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 12, 2015, 12:29:45 PM
Thanks Pete I'll bear that in mind, but I hope NOT to go diving in this dumper  :ddb:

The two new injectors arrived today, so now I have another 'oily hands' day ahead of me fitting those, and doing an oil change and fuel filter change.

I also made a momentus decision - that the seat WAS beyond repair and needed replacing. I put this expense off until I got the engine running, silly to give the scrap yard a new seat! Amazingly eBay has provided the exact same KAB seat  - even down to the spacing of the mounting holes so that's a bonus.

Would have fitted them today except I was told that I had to take SWMBO out for lunch followed by watching the latest James Bond film - escapism but how they can say that level of violence is suitable for 12 year olds is beyond me - no wonder we have delinquents in society  :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: tom osselton on November 12, 2015, 03:55:51 PM
I haven't watched James Bond in years the older actors were the best I prefer Mr Bean!
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 13, 2015, 08:24:06 AM
So between the showers this morning I set out to change the injectors, do an oil change, and change the fuel filter.

Injectors first - loosened off the overspill banjos, released the pipe, and decided one banjo bolt was a bit manky on it's hex flats. Had a spare so went to get it and idly screwed it into one of the new injectors that was on the same bench - or rather I didn't - the new injectors are a different size - like mine on steroids  :bang:

So that's one job that won't get done today - apologies from the supplier but that doesn't help me today  :(

I'd intended to test the injectors and set up tick over speed whilst the engine was warming up for the oil change - never mind we ran ok on the old ones, and when warm changed the oil filter and oil, and fuel filter (which was unbelievably mucky)

A courier arrived while this was happening with the new seat, so I'm afraid his hand held signing pad got covered in oil - sorry !

Hope to start putting the 'bodywork' back on tomorrow if there's a dry spell - then I can attack the brake master  cylinder fault.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 13, 2015, 09:21:48 AM
Oh I almost forgot - that rubber 'dust valve' or 'vacuator' turned up in the mornings post and amazingly it fits (with a bit of stretch and some Hellerman oil) without trimming the flange, so that's ticked off the list.

Still ticking over a bit fast which I must sort somehow - it's the balance between the centrifugal governor and the injector pump return spring that I need to sort.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: ddmckee54 on November 13, 2015, 12:17:27 PM
Have you got a clamp for that 'vacuator'?  Without a clamp I can just see that thing getting launched to who knows where if the engine ever does back-fire.

Don
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 13, 2015, 12:23:27 PM
Don yes I had the same thought  :bugeye:

Perhaps a Jubilee clip round it would be prudent, but they never had them originally. My JCB 803 has a very similar one and again no original clamp - mind you the rubber bit WAS missing when I got the machine  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: AdeV on November 14, 2015, 01:13:41 PM
It's pretty rare to have one of those engines backfire TBH, about the only way you'll do it is if you spin it backwards, and even then the timing will be all wrong, you're more likely to hydraulic lock it than fire it in reverse. My guess would be the rubber simply got a bit rotten and fell off at some point in the past - especially if it's lived most of its life out doors.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 06:49:00 AM
So a bit more progress:

I'd had several instances of finding the battery flat overnight - I'd thought I'd perhaps left the ignition switch in the wrong position as there is no charge light fitted. The engine is started on the switch but stopped by pulling a lever on the fuel rail so it's easy to forget to return the switch to it's original position. However investigation showed that in fact the alternator was kaput - it is an obscure one whose external shape exactly matches the common Lucas ACR 17 36 amp one, but internally it was totally different and extremely corroded and clagged up. So rather than re-build it I bought a standard ACR 17 - they are available amazingly cheaply, and while I was at it I fitted a charge light.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 06:53:18 AM
In the process I also bolted all the bits of  bodywork back, having first thumped some with a BFH to give a semblance of being straight. This allowed me to fit the new seat and return the mended air filter housing to it's rightful place
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 07:01:55 AM
So now to the brake master cylinder, which is jammed absolutely solid. So I pulled up the floor to expose it for removal

It's made by 'Frenos Iruna' of Spain, and quite a bit of searching failed to produce a repair kit for it. Apparently there were two sources for master cylinders for this digger and mine happened to have the obscure one rather than a Girling  :(

Little choice really but to buy a replacement - ordered one an Saturday and it's supposed to be delivered today, but hasn't turned up so far - at least though I managed to fit the alternator.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 07:22:04 AM
So when the master cylinder is fitted all that remains to fix is the centre articulation pivot.

It's a rather complicated affair, with a 'lower bearing' that is just a spherical bearing bolted between two large lugs, and an 'upper bearing' that comprises a fish plate with spherical bearings inset at each end, with greasable pivot bolts going though both. Repair kits are available, but for silly prices - a tad under £300 each so that's not going to happen  :bang:

The complication is getting the old bearings out to examine them and re-engineer them. The individual spherical bearings are only £15 or so each from bearing suppliers dependant on size but until removed sizes are only a guess.

Now this centre pivot holds the machine together - remove it and the front and back of the machine part company  :bugeye: So some method needs devising to support and contain the two halves - I may even temporarily weld bars across the pivot then just grind them off later.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 08:26:25 AM
Well after lunch the new Master Cylinder arrived, along with the special oil. These dumpers have 'wet' (ie oil immersed) brakes, and the actuating cylinder and piston are inside the axle, so the hydraulic brake oil has to be compatible 'mineral oil' and not standard brake oil. In fact there is some thought that it might have been topped up with the wrong oil at some time hence jamming up as the seals swell - if that's the case the seals inside the axle will be questionable - but that cylinder currently isn't jamming so fingers crossed on that one  :med:

Unfortunately that wasn't all that arrived after lunch. We had a huge down pour, so work has stopped for the moment
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: vtsteam on November 17, 2015, 09:02:03 AM
Andrew, cool to see you on another project!  :thumbup:  :clap:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 17, 2015, 09:35:37 AM
Thanks Steve - I'm afraid that they are never ending  :clap:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: vtsteam on November 17, 2015, 10:43:10 AM
Good!  (I don't mean that in a bad way.....)  :beer:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 18, 2015, 01:26:08 PM
Bit of a frustrating day today  :bang:

I did manage to fit the new Master Cylinder for the foot brake, but when I came to bleed it I couldn't for the life of me find my little red rubber bleed tube - you know the thing - thick walled pliable rubber with an aluminium rivet in one end and a fine slit. Other end goes on the nipple and the slit acts as a one way valve. I KNOW that I have one, but where - not used it in years - never mind - ordered up a new one - a long one this time so maybe I can watch it AND pump the pedal, as getting SWMBO  involved in brake bleeding is a recipe for arguments !

So never mind - re-fitted the floor having first filled up the front axle casing, rear axle casing and transfer box with oil, and greased as many grease nipples as were accessible. (Some on the UJ joints on the prop shafts (there are three prop shafts!) were totally inaccessible with a grease gun )

Then I decided to fit a horn. This dumper never had one, not really for warning when driving, but when you are working with someone else driving a digger, often you need to attract their attention. I had a brand new horn left over from my JCB 803 re-furb, so I bought a rubber covered 'heavy duty starter button - rubber covered'. Well it does the job, but the aluminium alloy body is a horrid screw fit to it's brass mounting nut - some one in China has a tolerance issue  :ddb: Managed to squeeze the horn under the mounting for the drivers seat, with the button on the panel that the ignition switch mounts on, as that was where I was picking up a live feed from.

I took it for a drive round the yard. Hairy experience with no foot brake, and dramatically better performance than previously - however I noticed that the steering ram that flexes the articulated steering is leaking. Not surprising - the end eyes are well worn, I have a line on one from a dumper being scrapped.


So - twiddle thumbs time till the tube arrives .......
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: edward on November 18, 2015, 07:31:18 PM
Could you get one of the gunson easi-bleed caps to fit the reservoir for the brake fluid? They are way better than the pedal pumping method if you can use them.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Manxmodder on November 18, 2015, 09:40:17 PM
 
 I can watch it AND pump the pedal, as getting SWMBO  involved in brake bleeding is a recipe for arguments ![/b][/u]

 :lol: :lol: Oh yes,Andrew. I've been there a couple of times before now.

 'I thought I said press down and hold it there until I say up again!  :bang: :bang:....OZ.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 19, 2015, 06:34:11 AM
 :ddb: :ddb: We have Brakes  :ddb: :ddb:

The postman kindly brought the replacement brake bleeding tube this morning, and as it hadn't started raining (forecast though) I set too.First job was to find a way, in the absence of a helper, to keep the brake pedal pressed and definitely not released, until I had re-tightened the bleed nipple on the axle. I found that I could rig up a large 'Carver' welding clamp between the chassis and the pedal, so then I could go ahead.

Probably worth pointing out that this brake system is not like the sort that you get on a car - it has two sets of  oil immersed brake disks inside the axle, one either side of the differential. They are actuated by concentric cylinders and pistons, each with an 'in' and  an 'out' port on top of the axle casing. Fluid from the Master Cylinder is routed to one 'in' port, the 'out' port of that cylinder is piped to the 'in' port of the second cylinder in rigid pipe, and that cylinder's 'out ' port has a bleed nipple in it.

The process its, slacken bleed nipple with tube attached, depress brake pedal and fix it down, tighten bleed nipple, release pedal slowly so master cylinder re-fills, then repeat the cycle.

As I was far from sure that this system had been filled with the correct mineral oil fluid that is compatible with the seals (Not one of the standard 'DOT' fluids), I wanted to flush out all the old, so it's good that the cylinders are in series rather than parallel.

Got it all set up, rubber tube on nipple, catch flask in place, then the rain started. Hang it carry on, just get wet  :bang: The old fluid was a very different colour from the new, so it was quite easy to see when we went from old, to mixture, to new just from the colour. Interestingly there must also be a marked difference in the viscosity, as, as soon as the new fluid started coming through, depressing the pedal became much easier forcing the fluid through the bleed nipple. Got through two complete reservoirs of fluid in the end.

As you can see from the picture, the old stuff was in a right mucky state. Smelling it I think it was a mineral oil, but not the right stuff. (I've been sniffing bottles of DOT3 DOT4 and DOT5 brake fluid, I hope nobody notices and gets me taken away  :clap: )

Pedal seems pretty solid (air in system gives a spongy pedal) and driving it back and forwards the length of my loading dock it works OK, but by this time it was pouring down and time to clean up.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Pete W. on November 19, 2015, 06:53:21 AM
Hi there, Andrew,

I've had three different Citroens that floated on LHM.  When I was far from home and suffered an LHM leak on the first one, the RAC roadside rescue bloke told me that 'the book' says it's OK to use a light mineral oil if LHM isn't available.  To be sure, the recommendation is to have the system flushed and refilled with LHM as soon as possible.

Maybe the previous owners of your dumper followed the first part of the routine but didn't bother with the second? 
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: vtsteam on November 19, 2015, 02:58:37 PM
Oh man, yelling to the lady in the drivers seat "Now hold it down!" while lying upside down under the car with a wrench on the slave cylinder, opening it up and brake fluid squirting in your face, and dripping down your arm, and she in front letting off the brake before you got it screwed back on, sucking in the air........ those were the days!

Eventually I got so I could prop my heavy tool box on the brake pedal, scoot under the car, loosen and tighten the screw before the pedal hit the floor. Well before I discovered the tube in the jar method.  :doh:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: edward on November 19, 2015, 07:08:33 PM
I went through that pedal-wife-swearing cycle a few times and in the end I bought an easi-bleed kit which uses a reservoir pressurized using tyre pressure to drive the fluid through from the header - just open the bleed nipple, let the fluid flow and then shut it off when it flows clean or you have collected enough to be sure it has changed everything in the line. No danger of air sucked back in or anything.

All fine until you snap a heavily corroded nipple off in the cylinder. Much swearing ensued!

This is all on conventional cars though, the dumper seems to be a whle different kettle of fish:)

this one http://www.amazon.co.uk/Gunson-G4062F-G4062-Eezibleed-Kit/dp/B001KTFIWA/ref=sr_1_4?ie=UTF8&qid=1447978388&sr=8-4&keywords=brake+bleed+hose
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 20, 2015, 02:39:38 AM
I agree about the Eezybleed , it was one of those I couldn't find. I can see it in my mind, tallish square cardboard box, predominantly yellow, with a plastic reservoir and various master cylinder caps, and of course the pliable rubber tube. Now I've done the job you can guarantee that it'll show up any day now.

The possible second hand steering ram turned out to be a different shape. I've bought a seal kit for the original ram, and assuming it dismantles ok I'll have to find a way to re-engineer the end eye to lose the gross wear. Maybe build up with weld and re-machine, or possibly cut off and weld on new.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: edward on November 20, 2015, 03:27:39 AM
I feel your pain. Recently spent longer than the job should have taken looking for my oilfilter socket. Of course the blasted thing turned up in a different tool box the day after the replacement arrived!
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 10:08:56 AM
Time to attack the steering ram that articulates the front and rear of this dumper. It's leaking hydraulic oil quite badly, and it's spherical bearings (rod and cylinder) are badly worn.

I'd sourced a set of seals for it that are allegedly correct, but the supplier couldn't give me actual dimensions,  there is no guarantee this cylinder is original so it was a bit of a chance if they fit.

So first whip it off having moved ram to closed position to expel as much oil as possible and identified the hoses and blanked them off.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 10:14:44 AM
Then the moment of truth - dismantle the cylinder and compare new set of seals.

First remove the end cap - these frequently are horribly stuck, and I've been putting 'Plus-Gas' on the threads of this one for the last few days - it came out easily  :thumbup:

Certainly the new seals do look to be correct  :thumbup:

- it's a 1" rod and 2" bore cylinder - supplier could only say "about 50 mm on the outside" which isn't close enough in this case  :bugeye:

The rod seal is probably the leaking one, but I'll change all of them
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 10:21:28 AM
Next the spherical bearings - they were HORRIBLE  :lol:

They are welded on 'attachments' to the rod and cylinder with a 1" bore to the sphere itself, but I couldn't find any - only metric ones, and if I were to use those I would have to cut the mounting lugs off the dumper itself and make metric ones as well as 25 mm pins.

The eyes will need slicing off the rod and cylinder end whatever I use, for the replacements to be welded back.

I did however find a source of 1" 'spherical inserts' that have a parallel outside, so I'm going to turn up a housing for them and weld the housings to the cylinder and rod end. They are on order so a bit of delay in the proceedings.

I decided to make new pins anyway as the old are rather worn
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 10:30:45 AM
Now the pins are simple affairs! Just a 4" length of steel bar with a tab welded on one end for a locating bolt to stop it turning, and a co-axial hole up the lower end for a grease nipple, with a radial 3 mm hole for the grease to squirt out of into the spherical bearing.

I had some EN8 1" bar to hand but it could as well have been mild steel. So I set too making bits. First cut the components, then drill the various holes, then weld them up - how hard can it be  :clap:

The shaping of the keeper plates was done free hand on the sanding table - shape isn't critical
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 10:34:47 AM
I decided to give them a light nickel plating to stop the rust. Can't be too heavy as it's easy to plate a pin so it no longer fits - ask me how I know  :bugeye:

They were sand blasted and I didn't polish them before plating as the job doesn't warrant it. A quick 15 minutes in the plating tank and a trial fit
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Spurry on November 24, 2015, 12:59:58 PM
Sorry to be dim, but what is that gadget in end-cap-removal.jpg photo. I've obviously lead a very sheltered life. :scratch:
Pete
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 01:04:32 PM
It's an adjustable pin spanner - it is adjustable for spacing of the pins, and the pins themselves are interchangeable (I have a selection of different diameters
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: appletree on November 24, 2015, 03:30:15 PM
It's an adjustable pin spanner - it is adjustable for spacing of the pins, and the pins themselves are interchangeable (I have a selection of different diameters
Nice bit of kit, like me you appear to have lots of tools, abilities, and experience to carry out most tasks. Where did you gather all this? 
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 24, 2015, 03:40:03 PM
Question of necessity really - when thing's are broke, and you are broke, no one else is going to fix them for you  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Spurry on November 24, 2015, 06:00:18 PM
It's an adjustable pin spanner - it is adjustable for spacing of the pins, and the pins themselves are interchangeable (I have a selection of different diameters
Thanks Andrew. I've never seen one of that type before. I guess it would remove very heavy circlips too. :thumbup:
Pete
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 25, 2015, 10:18:38 AM
A bit of progress today - the spherical bearings arrived, but not the circlips to retain them.

I made a start on the housings for the bearings - I had a bit of unknown origin 2 3/4" bar that seemed a likely candidate as the original housings are 2 1/2.

Faced it off and reduced the outside to 2 1/2" then drilled it 1 5/16" - it needs boring out accurately to 1 5/8" but I will leave it over night chucked up to return to room temperature.

Looking at the way it turned, I suspect that this bar is a bit more than just mild steel, a good thing for strength just so long as it welds ok.

...why drill to 1 5/16" ? Well it's the largest drill I have on a 3 MT shank and to use a nearer one to finished sized I'd have to use a 'jump up sleeve' to 4 MT and although I have one, the whole caboosh gets very unwieldy.

I need to grind an internal grooving bit to make the circlip grooves, but can't do that yet as I need to measure them first.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: AdeV on November 25, 2015, 11:40:30 AM
You mean to say you haven't trimmed your 4MT shanks down to 3MT?

Sounds like a job for the CNC lathe...!
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 25, 2015, 12:06:18 PM
But I have 4 MT in the spindle of my Richmond 3 foot radial drill so why booger them up  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on November 25, 2015, 12:48:15 PM
Question of necessity really - when thing's are broke, and you are broke, no one else is going to fix them for you  :lol:

Having seen your workshop, I suspect that is also a certain amount of satisfaction in making things work!

All the best, Matthew.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: AdeV on November 25, 2015, 01:14:07 PM
But I have 4 MT in the spindle of my Richmond 3 foot radial drill so why booger them up  :lol:

Wouldn't it be easier to sleeve up from 3 to 4 MT than to sleeve down from 4 to 3?  :scratch:

Hmm... I have a big pile of drill bits/reamers with 4MT (and bigger) shanks on them, you interested in any of them?
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 25, 2015, 01:38:42 PM
Question of necessity really - when thing's are broke, and you are broke, no one else is going to fix them for you  :lol:

Having seen your workshop, I suspect that is also a certain amount of satisfaction in making things work!

All the best, Matthew.

OK Matthew, you've got me sussed  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 26, 2015, 11:40:00 AM
So today's task was to make the spherical bearing holders, as the retaining circlips had turned up.

First I bored the full length of that bar to 1.625", being careful towards the end to 'wash the heat out' with suds. Bearings were a nice snug fit (phew  :thumbup:

Then a slightly hairy experience cutting circlip grooves 'blind by numbers'. Went round the houses a bit as my first grooving tool rubbed (not enough front clearance) and I managed to work harden (*) that bit of the bore  :bang: - careful application at low speed of the next grooving tool that I ground got me past the hard bit, then it was a case of parting off and repeating.

Clearing the burrs raised by the grooving operation was a bit of a pain - ended up using a very fine 'half round' file. Then it was just a case of drilling, spot facing and tapping for the grease nipples.

I decided to fit a locating 'roll pin' in the housing to aid in location when they are being welded. When I chop the end off the rod I'll mount it up in the lathe using lead slips to protect it, and drill a hole to receive the pin. The one in the cylinder I'll probably have to do by hand. The idea being that it's only too easy for thing to move when you start welding, especially when you can't clamp them very satisfactorily.

Note that the orientation of the grease nipples is different between the two holders to allow access.

(*) which proves my suspicion that this is more than mild steel, or it would not have work harderned
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 26, 2015, 04:43:15 PM
Television was particularly boring this evening, so I escaped to the workshop for 45 minutes  :ddb:

I decided to remove the old bearing eye from the piston rod and prepare it for welding. First job, unjam the jam nut that holds the piston assembly onto the rod, then remove all the components, sliding them onto a long ty-wrap to preserve their assembly order.

Then off to the cold saw to saw off the old bearing eye, protecting the rod in sheet lead so that the vice doesn't do damage. I deliberately cut through the old eye to make sure that I don't shorten the rod.

Then mount up in the lathe, again using sheet lead as a cushion, and turn off the old weld, put a 45 degree chamfer on it to enhance weld penetration, and drill the end 1/8" to accept the roll pin for centring. Cleaning it up, the bit of the old eye neatly fell away exposing virgin rod on the end surface, so no rod shortening  :thumbup:

(I will of course be dismantling the bearing assembly before welding)



Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 27, 2015, 09:52:33 AM
So cut off the cylinder eye then welding today - but first I had to go and pick up 250 kG's of Sow Nuts from the feed store and hump it into it's storage bin  :bugeye:

Set up the cylinder in the cold saw ready for chopping - problem is that being hollow you daren't tighten the vice or it will distort, hence the packing under the eye. Chopped off the old eye, cleaned up the raw end and marked it for a hole for the location dowel pin. Can't go in far as the end wall is only 5 mm by my measurements, so just a dimple really.

Clamped up and welded the new rod eye and cylinder eye. It would have been so nice if I could have 'rolled' the rod on the welding bench to run a neat bead round it, but obviously the surface of the rod would have suffered from the arcs from the bench contact. Had to do it in fits and starts, protecting the chrome with wet cloth (which steamed up my welding mask  :bang: )



Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 27, 2015, 09:54:40 AM
Then it was just a case of putting the piston assembly back together with new seals and a bit of a clean up.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 27, 2015, 10:04:50 AM
Then I got a bit enthusiastic and decided to give it a coat of paint. Quick clean and degrease using IPA, mask it up then a coat of etch primer, which was given an accelerated drying time by using a heat gun.

Followed the etch primer with a aerosol can of satin black that covers a multitude of sins - matt black is even better but I'd run out  :lol:

Bit of a cook with the hot air gun, take off the masking tape and put it back on the machine, giving everything a good grease up. I hate grease guns - they always run out just as you want to use them, then putting in the new cartridge, which should be so easy, always seems to end up with grease everywhere  :bugeye:

Never mind - ram is back on and pivot pins and bearings greased up, hydraulic fluid bled though, and woo-hay - she works  :ddb: Steering is so much more positive, less jerky AND there are no leaks from the ram. It won't last for ever, as there are a few dings on the rod - if I'd realised I'd have made a new one as it's only 1" hard chromed rod stock with a shoulder and thread at one end.

Still - I'm a happy bunny. Just need to ponder  whether I can be bothered to sort out the centre articulation bearings - looks like at least two skinned knuckles if I do  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Spurry on November 27, 2015, 11:39:20 AM
Another brilliant job, Andrew. Thanks for sharing.
Pete
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 28, 2015, 06:30:51 AM
Thanks Pete for the kind words.

.... but a bit of thinking has left me deciding that that centre pivot definitely needs sorting - there is at least 1/4" play in the bearings - perhaps more, with the result that the thing clanks all over the place.


The front of the machine is hinged to the rear by three self aligning spherical bearings arranged at two levels. The lower pivot, which seems to have very little play in it, is just a single bearing. Whereas the upper arrangement is a bit more complicated - it has a 'fish plate' of 1" thick 3" wide steel 17" long, each end of which has bearings inset into the thickness. There are grease seals jammed above and below the bearings which are lubricated by co-axially drilled grease runs in the pivot bolts

The whole upper bearing assembly is available as a repair kit, but at £293 it's rather pricey  :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 28, 2015, 06:47:07 AM
Now I've rather ignored this problem for a long time, as it's not the easiest of things to get off and work on.

Firstly, undo it, and the dumper falls into two bits  :bugeye:

Secondly, the rear fixing of the 'fishplate' is very badly obscured by the hydraulic steering orbitor.

Now in a flash of inspiration I've decided that, so long as I leave the lower bearing intact, and suitably weigh down the bucket so it tends to collapse backwards (weight at the moment empty tips it forwards) I can support it on axle stands if I can somehow get at that rear fixing.

Now here comes the clever bit - slice the entire steering support assembly off with an angle grinder and put it to one side - finish the pivot repair, then weld it back on  :ddb:

This has the advantage of killing two birds with one stone. When we moved here, the very helpful hi-ab driver LeRoy foolishly tried to lift the dumper off his lorry using this steering support assembly, and pulled it entirely off the machine  :bang:

It had to be quickly welded back so the machine could be moved as it was obstructing everything else, and the only welder to hand was my old MIG BUT NO GAS  :( It didn't help that it was pouring down as well. So it got glued on as a temporary fix eight years ago, and has never been re-done  :palm:

They must be the grottiest welds I've ever made, but they have at least lasted, so this gives the opportunity to cut them off and hide the evidence  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 30, 2015, 06:49:35 AM
I bit the bullet at the weekend and ordered that expensive top link kit. I'd intended to pull out the old and see if I could re-manufacture it, but realistically I don't have the time as I can't measure the bearing until it's out, then several days waiting for bits, meantime machine cannot be moved. Costly but I think probably expedient.

The kit won't arrive until Tuesday or Wednesday so I've been giving some thought how to control the two halves of the dumper when I remove the original. I had thought that to weld a temporary strap between the two halves would be the way, but in practise I'll need to adjust their spacing in order to get the large pivot bolts installed. Just relying on axle stands is a bit dodgy, as they tend to slip as you strain on things balanced on them.

So I came up with the idea of taut lifting strops arranged so I can adjust the tension as I install the bits. The 'skip' has suitably tough handles welded to it in convenient places that will take shackles, and on the rear half a pair of 10 mm  deck hold down bolts were in just the right place to mount brackets. It was a simple job of boring holes in a bit of 6 mm thick 50x50 angle iron and bolting them, on  :ddb:

With a tourniquet rod put through the lifting strops and turned, I can fine tune the relative position of the front and rear halves of the machine, all the while keeping the lower pivot assembly in place
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: smiffy on November 30, 2015, 02:39:11 PM
Hi I have enjoyed reading you posts ,for many years I worked on all manor of plant both large and small .When changing the centre pivot bearing I would tip the skip  onto a block of wood and lock the ram of with a length of angle ,them place a jack in front of the pivot,place a trolley  behind the pivot ,remove the bolts through the pivot and wheel the rear end backwards .If i remember correctly  this can be done without removing an of the pipe work , usually took about 2 hours from start to finish.
On a completely  different note many years ago i was the mechanic for the  coastal defence work near you at Fairlight cove which involved unloading 250,000 tons of stone shipped in from Norway on barges each carrying 10.000 to 15,000 tons. The barges were floated in at high tide the bilges pumped full of water so they settled on the sea bed them the stones ,each weighting a minimum  of 10 tones pushed over the side and at low tide they were loaded onto dumptrucks run  up the beach and unloaded and positioned using 5 tine grabs on 75 ton excavators. Very punishing work for both men and machines ,if i can find some pictures I will try to post them .Over a 6 month period we had 3 machines break down and go and get a swamped by the tide , a real recover problem as one was a D8 The other 2 both 75 ton excavators . Happy day
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on November 30, 2015, 03:17:45 PM
Hi Smiffy thanks for your posting. My wife walks the dogs at least once a week at Fairlight :)

Small world - I'd be interested in those photos that you mentioned.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 01, 2015, 07:42:04 AM
Pivot bearing kit not arrived yet, so I thought I'd get ahead of myself and cut out those horrible welds.

First I whipped off the floor board to give better access, then unbolted the steering orbitor and the cylinder that I re-built, and swung them out of the way onto the body of the machine, protecting the ram with thick cardboard against sparks.

Then I had at it with my 9" Makita angle grinder, followed by a bit of finesse'ing with the 4 1/2" grinder in places the big one couldn't reach. I had intended to remove the master cylinder and have it swinging on it's pipe, but in the end decided there was just about enough clearance to go under it  :bugeye:

Finally cleaned it up with a grinding disk on the big Makita  - I've not yet touched the column itself.

I'm tempted to make it 'bolt on' when it goes back - the column will need extending anyway as it's lost material (The steering orbitor was a jam fit, squashing it's hoses), so I'm thinking to weld some heavy angle to the column, slightly off the bottom, and drill and bolt it to the dumper chassis. Then the welding can be done on the bench even if it is raining  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 01, 2015, 10:45:23 AM
This afternoon I attacked the Steering Column Stanchion. I'd intended to just grind back the grotty welds, but I decided it would be more satisfactory to slice off a section back to clean metal. The base angle was a bit squiffy - I decided to try and make it so that the face of the stanchion was approximately parallel to the back of the skip, as that's how they seem to be in various illustrations.

By the time I'd 'adjusted' the angle and got back to solid metal, at least 1" has gone from the length. This doesn't matter as the steering hydraulic orbitor mounts on a bracket that fixes on the two holes you can see in the face of the stanchion - all I have to do is drill another pair of holes a suitable distance further up, and, as the steering column just threads through a large grommet in the top of the stanchion it will just poke through a bit more and the wheel should end up about the same height.

I've abandoned the 'bolting on' idea - I'll just glue weld it back on otherwise it gets too complicated
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 02, 2015, 09:29:16 AM
.... now about that bracket idea .... I used to be undecided, but now I'm not sure  :lol:

My objection to fixing the stanchion back with brackets was having somehow to bend an odd angled one for the front edge due to the rake of the assembly, and getting a hand in to fit nuts to the bolts. But hang on there chappy - if you had a plate welded on the base, with suitable holes to fix it to the chassis, NO NEED for bending at all  and the chassis is thicker than the nuts - so tap the holes :ddb:

I rescued a bit of 1/8" plate that had been kicking about in the stable for a few years - it was the back of an electrical control panel, so had a fair few holes in it, but is was available  :thumbup:

Propping the stanchion up with a bit of wood to get the angle right, I marked out a suitable bit, cut it with the small angle grinder, and drilled M8 clearance holes in it. Then offering it up to the chassis I drilled and tapped the first hole to keeping it from moving about, then drilled and tapped the other eleven holes.

After a bit of a clean up it was reasonably presentable, so I welded it onto the stanchion, drilled the replacement orbitor mounting holes a couple of inches further up, then sand blasted it. It's really too big for my cabinet sand blaster, and too small to be bothered getting the full size one out, so I struggled in the cabinet. It fits but it's mighty hard to see round it to make sure everything is blasted.

It came out not too badly, and got a coat of zinc rich primer which I left drying while I made bacon sandwiches for lunch ... mmmm.

Then it got a top coat of bright orange. I have a few rattle cans of this colour left over from another job - it was a close run thing, it nearly got satin black  :ddb:

It's hanging up in my improvised paint drying oven, otherwise known as a 4 kW fan heater balanced on some fire bricks  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on December 02, 2015, 11:06:51 AM
A better solution!

Regards, Matthew.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: seadog on December 02, 2015, 02:01:48 PM
You realise that the more parts you paint, the more you'll need to paint. Bite the bullet and give it a full respray  :thumbup:

Another interesting thread by the way.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 02, 2015, 05:51:16 PM
... oddly enough it looks as though it's been that violent orange colour before, distinct shades of it were revealed as I sand blasted the stanchion  :clap:

Seriously though I don't see the point of a complete re-spay. A quick blow over is '10 yards pretty', but close up looks terrible. To totally dismantle and do a 'proper job' is a major task that  not only do I not have the time for, but frankly it's not worth it. It's next job is to move a pile of pig poo to the compost heap, followed  by a load of saplings I'm grubbing out from a stream bank to plant up a hedge. Following those jobs it won't look very pretty even if it had been painted !

Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: lordedmond on December 03, 2015, 03:12:17 AM
Great resurrection job again Andrew

But please tell me where to buy the clock you use that can expand time to enable me to fit 50 hours of work into 24  :D

Mend this , look after the live stock , maintain the plant , maintain the cottages and house and keep the wife happy not for getting the viber's

Keep at it one day you may be able to put your feet up

If you need a chalange I would have sent you down my uncles Jersy bull ( killer , black head and black by nature ) we use to tie his ring to the front of the fordson major to get him out of the loose  box , but if the cows were in the yard he would come though the door smashing the place up

Stuart
Stuart
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 05:46:25 AM
It's not that relentless Stuart  :clap:


However just as things seem to be going well, there's always a 'Gotcha' to come along and nibble your nether regions  :bugeye:


Today the tracking data told me that ParcelForce were due to deliver the replacement centre link / pivot / bearing thingy, so I thought that the sensible thing to do would be to loosen the pair of 1" bolts that hold it on. A bit tight but my 3/4" socket set and a scaffold tube got them turning  :thumbup: Then the HORRIBLE TRUTH dawned on me - the rear bolt has it's nut on the upper side, so the bolt has to come out DOWNWARDS. But the transfer gear box is in the way  :bang: Whether this is by design or a mistake at original assembly I don't know - the front bolt (that is EASY to get at) is the other way up ! It does seem that there is room for the nut to be at the lower end.

Now the transfer box is held on by four bolts onto the chassis that are fairly hard to get at, and the three prop shaft flanges would need to be removed - not impossible, but definitely a pain in the rear.

Only alternative I can see at the moment is somehow to cut the head off the bolt in-situ, and install the new one the other way up, but cutting through a 1" bolt in a very cramped spot won't be easy.

I'd just cleaned my self up to type this when Adrian the ParcelForce man arrived with the new pivot bearings.

So any suggestions, or volunteers to drop the transfer box, are welcome - don't be shy
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on December 03, 2015, 06:08:15 AM
Andrew,

is the reason it's that way up so that you can get at the grease nipple? What ever, it has to come out, wouldn't it maybe wiggle pas the drive flange with the prop shaft off, or even with the output flange pulled?

I won't be over till the end of the month maybe a bit late to help!

Good luck! Regards, Matthew.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: lordedmond on December 03, 2015, 06:45:55 AM
It's not that relentless Stuart  :clap:


However just as things seem to be going well, there's always a 'Gotcha' to come along and nibble your nether regions  :bugeye:




Only alternative I can see at the moment is somehow to cut the head off the bolt in-situ, and install the new one the other way up, but cutting through a 1" bolt in a very cramped spot won't be easy.



Andrew
Get the vet over they have just the thing  embryotome would do it  :Doh:


Stuart
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: AdeV on December 03, 2015, 02:07:41 PM
OK, this may be a bit too extreme... but let's see:

First, undo and remove the nut.
Second, gas-axe/plasma-cut a piece of the upper plate out, sufficient that you can lift the pivot up a bit
Gas-axe/plasma the bolt head off, between the pivot and the lower plate. Presumably the remnants of the bolt will then fall past the prop & out of your way. If the rest of it doesn't follow, push it through.
Weld cut-off back into place.
Install new nut/bolt the right way up.

I guess it depends if you want to cut the plate or not, it looks pretty thick to me.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:16:58 PM
Well chaps many thanks for your interest and suggestions  :thumbup:

There was of course only one way really to do this - drop the transfer box - just get on with it and don't be a wimp  :ddb: I reckoned that if I disconnected the short propshaft at the gearbox end, there should be enough travel in the splines of the other two propshafts just to lower the transfer box enough to remove the offending bolt.

So rather reluctantly I crawled under and started spannering. Propshaft was easy - there were only three loose bolts in the four bolt flange  :bugeye: The four bolts holding the transfer box comprised two easy ones, one that was a bit of a challenge, and one the was a nightmare - but I got there in the end and managed to lower the transfer box on the trolley jack, and prop it up on bits of timber, as the jack was needed to get the chassis on axle stands.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:21:11 PM
Then,having put axle stands under the chassis I put the tourniquets back, and carefully tweaked them so that the top pivot bar assembly was in the middle of its play so that there was no strain on the big mounting bolts.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:26:43 PM
This is where I should have been able just to unbolt the old pivot and pull it out. But lifes rarely like that is it  :hammer:

The front bolt was fine, but the rear one refused to budge. It's nut unscrewed ok, but with loads of 'Plus-Gas', much hammering on spanners, and heating with the oxy-acetylene torch it wasn't moving one iota. Even a 14 lbs sledge hammer failed to knock it through   :bang: Having exhausted all other possibilities I decided to drill it out using the mag drill.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:38:30 PM
Then the fun began. Firstly the magnet switch on the drill decided now was the time to weld it's contacts in the 'on' position.  This  made positioning it rather difficult. However, as there was a grease bore down half the length of the bolt, at least there was something for the drill to follow.

As I went progressively up in size I got to a point where the drill was wandering dangerously off centre, threatening to mar the mounting bushes. So I stopped with the bigger drills (I think I'd got up to 18 mm on a 1" bolt), and went right through with a 1/2", so leaving me a shoulder inside to put a drift against. Then I got the oxy-acetylene  torch out again and heated through the hole downwards, so at least the stuck bit was getting the flame.

A short length of rebar as a drift and the sledge hammer at last persuaded the bolt to move downwards - what a palaver  :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:45:29 PM
Quelle relief !

So now I transferred the adjusting / limiting bolts from the old to the new pivot, making sure that they were set to the same height as before. No idea how this is supposed the be adjusted so I thought it best to accurately copy how it was set. I then installed the new pivot, which went ok apart from getting the grease seals in place - they got there eventually but trying to squash two grease seals and slide the pivot bar at the same time was  great fun  :clap:

Then back under and bolt the transfer box and propshaft flange back, along with the steering ram. (I'd removed the ram in case the front and rear of the dumper had moved apart, as it might well have bent the ram)

Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 03, 2015, 02:55:34 PM
Now those who've been paying attention will notice I've put the rear pivot bolt in just as the original one was. Matthew is quite correct, with it the other way up you cannot get at the grease nipple. In an ideal world I would have drilled the bolt all the way through, plugged the 'nut end' and tapped the head end for a grease nipple. But time was getting on, I was knackered, and I reasoned that it would last a good few years as it was.

So lack of light stopped play. Tomorrow the steering stanchion goes back on, then the steering orbitor, and a few odds and sods like floorboards.

I noticed that one of the hydraulic lines for the ram has suffered a bit, so if I have the correct fittings I'll crimp up a new one.

... so now it's time for a bottle of Ibuprofen and a wee dram as I have aches in places I didn't know that I had  :clap:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 04, 2015, 08:44:43 AM
A relatively easy morning today. I bolted back the steering stanchion, installed the steering orbitor and checked that it all still worked. Then removed the temporary 'tourniquet'  brackets, and bolted back the floor.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 04, 2015, 08:50:29 AM
While I was fitting the steering orbitor I noticed that it's shaft oil seal was weeping. Seems to be an externally fitted 1" shaft 1 3/4" o/d of perhaps 1/4" or 3/8" thick. I ordered some up but carried on installing it as it's only 4 bolts to drop it off in the future when they arrive.

Also the pipes to the steering ram were pretty horrid - as they were previously fitted they were squashed at a difficult angle against the floor. Having raised the orbitor a bit they fit much more comfortably, but needed replacing. Fortunately I had the correct fittings and hose in stock so crimped up a new pair.

With the new stanchion arrangement the wheel is perhaps a bit to far forwards - I may have to work out how to move the seat forwards a bit.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on December 04, 2015, 09:43:37 AM
Nice to see, as usual!! I like the one bit at a time paint job.

I might pop in for a cuppa between xmas and the new year. All the best, Matthew.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 04, 2015, 12:29:51 PM
Be good to see you again Matthew  :thumbup:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: appletree on December 04, 2015, 12:57:50 PM
A relatively easy morning today. I bolted back the steering stanchion, installed the steering orbitor and checked that it all still worked. Then removed the temporary 'tourniquet'  brackets, and bolted back the floor.
How do steering wheels end up that shape? and does it hurt? we had several of the same machine inner fleet a number had the same steering wheel.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 04, 2015, 01:27:06 PM
I have always assumed that it's the constant exposure to weather releasing stresses from the moulding process that distorts them. Works ok as it is and a new one is £45  :bugeye:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Spurry on December 04, 2015, 02:04:03 PM
Andrew
This will be a mighty posh dumper by the time you have finished. :clap:
Pete
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 07, 2015, 07:39:06 AM
It'll still be a tatty dumper, but at least it'll work  :clap:

The oil seal for the input shaft of the steering orbitor arrived this morning, so I disconnected the four hydraulic pipes, capped them and got the orbiitor out and in the vice. Very close examination showed that what looks to be an oil seal pushed in from the outside, is actually a turned feature of the body , and the seal lips that are clearly visible, must be from an internally mounted seal - not entirely surprising  :bang:

Having watched a youtube video of someone pulling a similar one apart I decided that that was not a course I wanted to go down !



Then in a flash of grey cells being resurrected I remembered that I had an orbitor I'd bought nine years ago as a spare for my JCB 3CX - I don't suppose that it's possibly compatible is it  :scratch:

I went searching and found I actually had two different ones on the shelf - the other came of a Buchner 'bank mower' that I had got rid of years back - seems the same size but the hydraulic ports were a different thread. However the brand new, wrapped up in waxy paper JCB 3CX one had the correct port threads, but it had a small fifth port. I suspect that this port is a 'weeping port' returning any leakage back to the tank - but I had no plumbing in place to do that.

Rightly or wrongly I decided to blank it off - but what size is it and do I have a suitable bung? Well it wasn't metric, nor was it BSP or Whitworth or BSF - it had a plastic keeper in it which measured roughly 0.435" - now many hydraulic fittings use UNF - could it be 7/16" UNF  :scratch:

Looking through my quite sparse UNF bolt collection there were none to be found to use as a trial - but hang on a minute, the draw bar thread of a Bridgeport is 7/16" UNF. I whipped out the draw bar and sure enough that was it.

A quick trip to the lathe produced me a nice little 7/16" UNF hex headed stopper, which went in with an 'o' ring and a bit of thread seal.

Now the time to test it, as these orbitors come with widely differing specifications in terms of the volume they pass to the steering cylinders per turn of the steering wheel, and whether they self centre or load sense. Well to cut to the chase, it went in nicely, and as far as I can tell from a quick test drive performs exactly as the original one did except that it doesn't leak  :ddb: :ddb:

So that's one more thing ticked off the list. The spool valve for the tipping skip has a slight weep - nothing too bad, and as it's a very standard two way self centring jobby, if one turns up in the future at a sensible price I'll change it - otherwise it'll stay as it is.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 07, 2015, 12:57:01 PM
A bit of Googling implies that the 'extra' small port on the Saur-Danfoss steering valve / orbitor is probably a 'load sensing' output used in systems with a load sensing feedback path.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 10, 2015, 11:04:27 AM
I discovered a twist in the tail using the dumper today!

I was shifting the wife's compost heap 'rejects' (Clive the Gardener had heaped a load of woody trimmings that won't compost down on it) to the bonfire pile, only to discover that it wouldn't tip the skip unless you wiggle the steering wheel back and forth  :bang:

I can only assume that the feed from the pump goes via the 'P' and'T' ports on the steering orbitor and onwards to the spool valve for the skip cylinder, and that the old orbitor let fluid though all the time, and the new one only lets it though when it's rotated.

It didn't stop me shifting three loads of twiggy bit and one load of pig poop, but it must look very odd as I'm tipping and rocking the wheel at the same time.  :lol:

If I manage to find another spool valve I'll plumb it up differently
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 11, 2015, 08:13:36 AM
OK I've been cogitating  :coffee: on this hydraulic issue and I could do will some input from any hydraulic guru's on forum   :scratch:


Symptoms: following replacing the 'steering Orbitor' with a brand new but different one as the old one leaked, the steering works fine, but the ram that tips the skip only moves if the steering wheel is rocked back and forwards.

I've steam cleaned off the spool valve that does the tipping to try and trace it's plumbing, but it's extremely hard to make out markings on it however a few pictures
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 11, 2015, 08:18:16 AM
Now there is one very odd thing that I hadn't before realised. There are two return paths for the oil back to the tank. Oil from the steering orbitor returns via a filter as I'd expect, but the oil from the spool valve returns directly at a low level in the tank - very odd.

This is the circuit as far as I can tell, and a picture of the tank showing one large output going to the pump, one input at high level via the filter, and the oddity input at low level
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 11, 2015, 08:25:02 AM
Now here come the assumptions  :bugeye:

I am ASSUMING that the old orbitor presented resistance to flow when not being rotated so that pressure was available to operate the tipping ram. (*)

I am ASSUMING that the new orbitor only presents resistance to flow when being operated, hence the tipping working if the wheel is rocked (*)

Now buying a new orbitor is out of the question as they are hundreds of pounds, so what's the solution?

If I were to insert a 'pressure maintenance valve' on the output from the orbitor is it likely to work.

Comments please from any hydraulic guru's :scratch: :scratch: :scratch:



(* See later posts - this is INCORRECT - it's the other way round, the new one is 'closed neutral' and the old one 'open neutral'
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: appletree on December 11, 2015, 11:21:21 AM
Just keep on rocking :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: smiffy on December 11, 2015, 01:58:24 PM
Just a thought but where is the PRV, is it built into the tipping valve or is there a separate  stand alone PRV   For the tipping ram to work from your diagram the P and T ports in the orbitor would have to be closed. If the flow went from the pump to the tipping valve and then to the orbitor  and then returned to the tank the system would work but priority would given to the tipping ram , not ideal but workable.The system can only work with one return  unless there is a priorty valve fitted in the system somewhere. Mike
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 11, 2015, 05:34:30 PM
A bit of 'google research' shows that there are two or more varieties of steering orbitor. Centre closed and centre open. In the neutral position the centre closed variety blocks P to T whereas the centre open variety, which I think I must have fitted, passes oil from P to T unless the wheel is turned.

I suspect, but yet to be proved, the solution is to fit an inline pressure release valve between the out port on the spool valve, and the P port on the orbitor. This way the spool valve will have pressure to operate, and when the wheel is turned so will the orbitor ...... I think ....
:scratch:

Again ... informed comments welcomed ...... :scratch:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: smiffy on December 11, 2015, 06:07:00 PM
This would depend on the tipper spool, is it open centre or closed centre . From your diagram it should be open centre.It could work if you feed from pump to p port on orbitor , t port to tipper spool  and tipper valve to tank but this is dependant on where  the prv is .Mike
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: modeldozer on December 11, 2015, 07:29:20 PM
It might be easier to repair the old steering control valve, repair kits are availeble.

On assembly there is one critical step as explained on page 10 of this manual
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/dev_216975.pdf

For more info search for "Orbitrol steering valve"

Abraham
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 12, 2015, 03:49:07 AM
I can only assume that there is a PRV built into the tipper spool valve. I can just about see a hex headed 'something' in the face where the UP and DOWN ports emerge.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 12, 2015, 06:41:52 AM
Modeldozer - thanks - an interesting link. The original one is a Danfoss though, not an Eaton

Now a few more facts discovered:

A/ The original is definitely an 'open neutral', ('ON' in the type number probably means this !) I can blow through from P to T. I tried linking out the orbitor so where it is in circuit is replaced by a straight though 1/2" bsp to 1/2" bsp conical connector, and sure enough the tipping ram works just as it should

B/ Before finding it was open neutral, I blocked the pipe from the 'Out' of the spool block to the orbitor with a stop end - this jams the spool block tight making the spool virtually impossible to move, and this of course is the state it's in when plumbed as per that diagram. It brings into question whether there is a pressure relief valve in the spool valve, as I'd expect it to open under these conditions  :scratch:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 12, 2015, 08:08:01 AM
Obviously the best solution is to replace the orbitor with an 'open centre' one, so I've just trotted off to the workshop to try blowing through the ORSTA one removed from my Buchner bank mower.

Sure enough it's 'open centre'  :ddb: -

I'd rejected it as it's ports were a different thread from the original so I couldn't directly use the original adaptors which were UNF. As the ORSTA is BSPP it's an easy thing just to order up the correct ones (two 1/2" BSPP to 1/2" BSPP 60 degree cone males and two 1/2" BSPP to 1/4" BSPP 60 degree cone males) which should turn up in a few days. Then, IF the ORSTA still works we should be cooking on gas  :clap:

Not been able to find any info on the ORSTA on line in English, so suck it and see !
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: AdeV on December 12, 2015, 10:15:50 AM
Hmm, you've got a stonking great big CNC lathe sitting there just begging to make adapters... and you've ordered them?   :scratch:

Maybe I'm just making excuses for buying a big CNC lathe myself....  :loco: :palm: :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 12, 2015, 10:48:45 AM
Wait till you find out how long it takes to tool up and create a program for  a little job on your Mazak Ade and you'll know why  :lol:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 17, 2015, 06:46:32 AM
So at last the hydraulic adaptors have arrived that will let me replace the (closed neutral) Danfoss Orbitor with the (open neutral) ORSTA one  :thumbup:

Simple nut and bolt job and a bit of plumbing. I'm using Dowty Seals (Bonded Washers) to seal the adaptors as I find them pretty reliable, and keep a stock. Then disconnect the hydraulic pipes and cap them for safety - don't want crud in the system  :bugeye: Unbolt the Danfoss, bolt in the ORSTA and re-connect the plumbing. Took about 25 minutes. So nice working on things that come apart easily - well it should - this orbitor (and others!) have been in and out like a fiddlers elbow  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 17, 2015, 06:56:28 AM
So does it work - Oh YES  :thumbup: :thumbup: :thumbup:

Now I can tip without having to rock the steering back and forth  :ddb: I do notice a difference in the orbitors though. This one takes more turns lock to lock than the other one, which is probably a 'good thing' as going over rough ground the implied extra steering force will be handy. (The orbitors are specified as so many cc's per rev of steering wheel, and with the volume of the steering ram together effectively set the 'lock to lock' turns ratio. However, as hydraulic rams like this one are asymmetric in terms of the volume opening or closing the ratio is greater in one direction than the other. The Buchner bank mower this orbitor came off had a double ended ram ie a rod protruding at each end which makes it  symmetrical.)

I notice that the tipping ram is weeping a bit, but I knew that and have obtained replacement seals for it. Job probably won't get done until after Christmas as I have a few hundred saplings to shift with the dumper before then.
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 28, 2015, 01:24:10 PM
Well - holiday season, knee deep in family so distinct limitations on 'activity' but a few nice things happened recently.

First: Matthew Tinker and his son Chris visited yesterday as he's over from France for the festivities. Always nice to meet other Madmodders and chew the fat.

Second: and the is really a FIRST ! Persuaded the wife to drive the Thwaites dumper which has let me (using the JCB803) strip about 600 saplings from the river bank and start re-planting them as a hedge. I've got perhaps 55 out of 75 metres of the new hedge planted before I lost the light (and the will to live  :bugeye:)

Third: While doing all this My Hermes delivered a parcel with the second hand 'tipper spool' that I've sourced - it's not identical, but came from another Thwaites dumper doing the same function, so I should be able to cobble it in and cure my oil leak on the original  :thumbup:

Now let me point out - it's a BANK HOLIDAY in the UK yet MyHermes DID A DELIVERY - now people knock them, but so far I've never had a problem.

So a few pictures to prove it happened. Firstly Penny driving the dumper with the first batch of saplings
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 28, 2015, 01:30:30 PM
And here is the spool valve - it looked for all the world like a wrapped up Praying Mantis - but fortunately it wasn't - it was a spool valve  :clap:

Same number of ports that seem to be marked up with similar functions. In slightly different places, and I've a feeling the bore sizes of the ports aren't quite the same - though it may just be a case of swapping over the adaptors. For instance the two ports to the steering ram look to be 1/2" BSP whereas the original is 1/4" BSP - needs further investigation
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on December 30, 2015, 06:55:29 AM
Just a little bit of progress today as my times been taken planting all those saplings into a windbreak hedge in very wet sticky muddy conditions where your boots get pulled off your feet and you loose the will to live  :bugeye: Still they are now in and at least I don't have to worry about watering them  :lol:

I decided I wanted to investigate the new valve before pulling the old one, so first step was to undo that attached 1/2" bsp pipe, and effectively that's ALL I've done as it put up a lot of resistance. I wanted to prove that it was the output from the main Pressure Relief Valve returning oil to the tank when rams were at their limits of travel, but the nut on the end of the hydraulic pipe was unbelievably tight. Ended up removing the relief valve (as that WAS what it was) complete with pipe, and applying gentle heat from a blow lamp and liberal applications of 'Plus Gas. If you look at the flats on the nut you can see it was very close to being 'rounded off' before it came loose.

Anyway, apart from a physically different layout it looks to be ok. So so long as I can get the operating rod in line with the spool as I mount it, it shouldn't be too difficult - just hopefully drilling new holes in the existing mounting bracket to correspond with this valve, and swapping the pipes over. But as the return to the tank from the PRV is to the base of the tank I may well have to drain it first. Might possibly be able to clamp it but in the end no bad thing to drain the tank I suppose.

Again a few pictures to prove that it happened  :ddb:
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: mattinker on January 01, 2016, 09:12:39 AM

First: Matthew Tinker and his son Chris visited yesterday as he's over from France for the festivities. Always nice to meet other Madmodders and chew the fat.

I got back yesterday, very nice to see you again, have a bit of a chin wag and see progress in the flesh as it were.

Thanks again, all the best and a happy new year!! Matthew
Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: awemawson on March 28, 2016, 10:33:05 AM
 OK I think I can finally draw a line under this refurbishment.  :ddb:

I managed to fit the replacement tipping ram spool valve. It had a totally different mounting lay out, so I had to make up an adaptor plate taking the original valve's mounting points and presenting tapped holes to suit the new one. Fitted nicely and I managed to get the operating rod in the same alignment as the original, just having to shorten it a bit.

Now the hydraulic ports were another matter. The original was BSP all round. The second hand replacement had a very odd coupling that I've not been able to identify -  20 tpi, but an o/d of 0.758" with a deeply recessed conical seal. No matter, the body of the valve was tapped 7/8 UNF on all ports, so it was a matter of sourcing 7/8" UNF conical male to 1/2" BSP conical male adaptors for input and output, and 1/2" BSP ones for the A & B ports of the tipping ram. All went together nicely, and I even got 'tip' and 'retract' the right way round on the spool valve (50/50 chance !)


So I thought that I'd replace the weeping sealing in the tipping ram itself. I put the skip into 'full tip', then extended the fork lift tines above it and secured the skip to them with strops. This let me safely disconnect the hydraulic pipes to the cylinder and knock out it's pivot pins - heavy bu@@@r

I've had the seals waiting for some time but have been putting the job off. The outer end of the rod is a design I've not encountered before, with the end cap retained by a heavy C ring. All the was visible from outside was a large circlip preventing the cap sliding into the cylinder. Turns out, you remove the circlip, push the end cap inwards leaving the C ring in its groove, then remove the ring. Clever design.

Replaced the piston and rod seals, put it all back together then cleaned it up and sprayed a couple of coats of zinc rich primer followed by satin black, as I did with the steering ram. Back on the dumper and it works a treat.

In a fit of enthusiasm I decided to sort out the 'rotating skip'. The skip sits on a massive thrust bearing, and is prevented rotating by a large pin that is spring loaded upwards, and released by a foot pedal. It's never worked in the nine years I've had it. If you managed to release the pin, it would stick down and be a problem relocating. After a bit of cleaning up, cooking with a propane torch, and jiggling about, it freed off enough to withdraw it and give it a good greasing.

This has allowed me to rotate the thrust bearing and re-pack it with grease. Easy enough to turn it unloaded, not sure what it will be like with 2 ton of rubble in it  :scratch:

So - that's about it - well I've a wheel and tyre to replace as one on the front  axle is off a one tonner and a bit narrow - I've got the replacement (good old eBay) - just a case of doing it

Title: Re: Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
Post by: Spurry on March 28, 2016, 12:34:28 PM
Excellent write-up Andrew. Shame it's come to an end, but I bet you're pleased.  :clap:
Pete