Author Topic: JCB 803 Saga  (Read 49426 times)

Offline vtsteam

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Re: JCB 803 Saga
« Reply #25 on: June 28, 2015, 11:33:20 PM »
Good to hear,Andrew!  :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline awemawson

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Re: JCB 803 Saga
« Reply #26 on: June 29, 2015, 02:54:20 AM »
Thanks chaps, and yes you're all welcome to come round for a B&Q  :beer:
Andrew Mawson
East Sussex

Offline dsquire

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Re: JCB 803 Saga
« Reply #27 on: June 29, 2015, 03:15:32 AM »
Thanks chaps, and yes you're all welcome to come round for a B&Q  :beer:

Thanks for the invitation Andrew. Looks like another sucess and I enjoyed watching.  :D

Cheers  :beer:

Don
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Offline awemawson

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Re: JCB 803 Saga
« Reply #28 on: June 29, 2015, 12:58:08 PM »
Thanks Don, and it's on going !!!

So those piglets produced 108 kg of. meat including 33 kgs of sausages and burgers - spent the morning collecting it, and curing the joints I'm hamming and baconing. Belly pork, tenderloins and a couple of legs are being kept back for roasting.

I actually managed to get a bit of play time, putting back the digger floor pan, and going over every grease point making sure that the grease is getting through. Replaced five missing grease nipples, changed some hard of access ones for 45 degree offset ones, but the hardest was on the boom lift cylinder lower eye. The shroud has been clobbered at some times preventing a grease gun fitting. It took a bit of nifty work with an angle grinder and cold chisel to remove enough of the bent shroud to get the old nipple out and replace it
Andrew Mawson
East Sussex

Offline awemawson

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Re: JCB 803 Saga
« Reply #29 on: June 29, 2015, 01:07:41 PM »
Amazingly I've got through two full cartridges of grease - the main ring bearing that the entire digger revolves on took 20 pumps of the gun at the four quadrant points (ie 80 pumps) and still there was no tell tale grease emerging ! Service is supposed to be four pumps at each quadrant.

I left the dipper end as I have a rebuild kit to fit tomorrow with all new bushes and pins so it seemed a little pointless to grease the old stuff !
Andrew Mawson
East Sussex

Online Pete.

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Re: JCB 803 Saga
« Reply #30 on: June 29, 2015, 01:12:44 PM »
Yeah there's nothing more fun than changing freshly-greased pins and bushes :D

Offline awemawson

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Re: JCB 803 Saga
« Reply #31 on: June 30, 2015, 02:58:08 PM »
So today's job was to remove the old bushes from the dipper, along with the 'banana links' and the 'bucket 'H' frame'

This is the general arrangement:

Andrew Mawson
East Sussex

Offline awemawson

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Re: JCB 803 Saga
« Reply #32 on: June 30, 2015, 02:59:14 PM »
First job, drop the bucket - then strip everything off
Andrew Mawson
East Sussex

Offline awemawson

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Re: JCB 803 Saga
« Reply #33 on: June 30, 2015, 03:09:24 PM »
So not too bad really just rather mucky. Now that lot were off I could inspect the various bits that wear. The bush location in the end of the dipper arm was worst being somewhat ovaled, as was the rod eye on the bucket ram to a lesser extent.

Long term both these will have to come off and (somehow  :bugeye: ) got onto the Bridgeport table and bored oversize for bushes to be loctited in, but to keep the job going forwards, for the time being I turned up a bush for the rod eye that largely lost the wear, and used magic on the dipper end  :ddb:

Magic in this case being Devcon Titanium loaded epoxy putty. The wear bush is a nylon sleeve, the original having completely vanished !. New one was a reasonable fit except for the outer inch or so where it bellmouthed. I pressed the bush in and packed the Devcon around and into the wear cavity, making sure that the grease passage was still free. I very much doubt it'll last long, but the stuff is rated at 105 Mpa compressive force and specified for building up bearing housings so we'll see  :scratch:
Andrew Mawson
East Sussex

Offline awemawson

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Re: JCB 803 Saga
« Reply #34 on: June 30, 2015, 03:22:01 PM »
The Devcon has already set rock hard on my 'control sample' that I left on the bench, but I'll still leave it a full 24 hours before I re-swing the bucket.

Pressing the second nylon wear bush into the end of the bucket H frame compressed it enough that it would't pass a 35 mm bucket pin  :bang: Fortunately I have a 35 mm reamer, albeit on a 4 MT, so I passed that through the bush with a spanner on the tang - it's still very tight but no doubt a bit of use will sort that out  :clap:

Then after I'd cleaned up a bit and fed the pigs, fitted that replacement right hand handle complete with it's custom moulded button, and also put the jazzy button tops on the left hand handle
Andrew Mawson
East Sussex

Offline mattinker

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Re: JCB 803 Saga
« Reply #35 on: June 30, 2015, 03:24:37 PM »
Andrew,

I always like seeing your post, since I visited you they are all the more vivid, I can put a face to the words and a picture to add to the photos! I don't know when I'll be getting over to the UK again, but I'll try and get to see you again and maybe taste some barbecued pork!

All the best, Matthew

Offline awemawson

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Re: JCB 803 Saga
« Reply #36 on: June 30, 2015, 03:27:36 PM »
Matthew it would be very nice to see you  :thumbup:
Andrew Mawson
East Sussex

Offline dsquire

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Re: JCB 803 Saga
« Reply #37 on: June 30, 2015, 03:29:13 PM »
Hi Andrew

Looks like you have this puppy all figured out. I'll keep watching.  :D

Cheers

Don

P. barbequed pork. mmmm
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Offline vtsteam

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Re: JCB 803 Saga
« Reply #38 on: June 30, 2015, 07:56:11 PM »
Andrew I made a similar backing for a new bush that I bonded into a hole worn oval at the front axle pivot on My John Deere Model M tractor 14 years ago, using JB Weld.

That tractor built my house, hauled logs for the sawmill and heat, plowed snow into 6' high banks, cut brush, carried gravel and sand all over the property, dug a pond, hauled bridge timbers, and buit a 600 foot long driveway..And it's hardly ever spent any time on level ground doing all that.

The repair is still completely intact and indistinguishable from the cast iron casting the pivot pin bushing is bonded to.
« Last Edit: July 01, 2015, 09:53:45 AM by vtsteam »
I love it when a Plan B comes together!
Steve
www.sredmond.com

Offline awemawson

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Re: JCB 803 Saga
« Reply #39 on: July 01, 2015, 04:06:07 AM »
Steve, that's very encouraging. My concern is how far I managed to force the putty down the side of the bush - its quite stiff and there undoubtedly will be voids. It's a nylon so wont be able the bridge cavities !

Put the wide ditching bucket back this morning before  breakfast, and it's all remarkably tight with virtually no wobble. A bit unsettling as I've only used diggers with wobbly buckets before where positioning was a bit hit and miss.  bit of use and the play will come back I'm sure.

Anyway I now can at last shift the pile of pig poo that been getting out of hand.

Next major job to do on this machine is replace the tracks and idler sprockets. One side is ok (ish) but the other is rather scrunchy with it's chain and sprocket well worn out. Bits are on order and should arrive later in the week
Andrew Mawson
East Sussex

Offline awemawson

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Re: JCB 803 Saga
« Reply #40 on: July 01, 2015, 11:15:58 AM »
Well the Devcon has at least lasted for one day's light digging  :thumbup:

Pig poop all tidied up, transported to the wife's vegetable patch compost heap, and the (rather large) entire heap turned over in a 'sides to middle' fashion.

The bad news it it's developed another oil leak  :bugeye: - I noticed oil dripping onto the left hand track. After a lot of fumbling about and wrapping dry towel around fittings one by one I've located it on the Main Relief valve block where the input from one of the pump sections enters. (This machine has three hydraulic pumps all on the same shaft on the engine). It's either the 'O ring' in the face seal on the pipe or the bonded washer seal where the pipe adaptor screws into the valve body.

Fortunately there is a removable section of floor to the left of the drivers seat giving access from above, and it's fairly open below if the cab is slewed to 45 degrees so that it's between the tracks. However try as I might I cannot get the fitting unscrewed  :bang: It needs special pipe fitting spanners.

Special man with special spanners coming tomorrow (same chap who did the hose on that Hedge Flail last year.)
Andrew Mawson
East Sussex

Offline mattinker

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Re: JCB 803 Saga
« Reply #41 on: July 01, 2015, 11:21:01 AM »
Your getting to know this digger too well too soon!

Regards, Matthew

Offline awemawson

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Re: JCB 803 Saga
« Reply #42 on: July 01, 2015, 01:05:11 PM »
Your getting to know this digger too well too soon!

Regards, Matthew

Ain't it always the way  :lol:

No doubt a few more gremlins will come out of the woodwork pipework before it settles down  :bugeye:
Andrew Mawson
East Sussex

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Re: JCB 803 Saga
« Reply #43 on: July 01, 2015, 04:18:32 PM »
I have a handful of old britool/king dick ring spanners heated and bent and with the ring cut for doing this work on our Brokk machines. I DID have an old bronze one with very heavy walls around the ring which worked for one particular purpose where previous steel spanners had spread but one of the guys at work used it and left it in the rubble :(

Offline awemawson

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Re: JCB 803 Saga
« Reply #44 on: July 03, 2015, 11:40:19 AM »
Well this is going from bad to worse  :bugeye:

Mr Spanner had van problems (Ford ECU packed up) so only got here today at lunchtime - got the fitting out only to find that the actual leak is the main aluminium housing having a crack adjacent to the fitting  :bang: :bang: :bang:

Needless to say they are like hens teeth, and every machine being broken currently seems to have been robbed already. JCB want about a grand for just the block without any of the gubbins.

Theoretically it should be possible to reverse engineer the existing block and make a copy, but in practise there are so many interconnecting threaded bores, most with a seat cut at the inner end for a relief valve or pressure setting valve that the chances of success are slim. It runs at 3000 psi so needs to be sound.

Talking to specialist breakers this seems to be a known problem, especially in hot weather. When did it happen - hottest July day on record  :(

At the moment my hope is with a breaker in Wales who thinks he may have one of unknown goodness, but still 250  :bang:

It's tempting to strip it down and attempt a repair using one of the low temperature aluminium solders - probably mill a channel with a ball ended cutter and fill the trench. (I think TIG welding is likely to distort things too much).

If the breaker turns up trumps, I'll fit his, and if it works use it, and if not attempt a repair on one of them.

In all not a good day  - the replacement tracks, idler sprockets and drive sprockets arrived yesterday so I'm in too deep to stop now - it's a bit like the addicted gambler who has to double his stake every time he looses to keep up with his stake :scratch:
Andrew Mawson
East Sussex

Offline vtsteam

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Re: JCB 803 Saga
« Reply #45 on: July 03, 2015, 11:59:18 AM »
Andrew, you can make one, I'll wager -- despite the number of interconnected channels. Hell, you've brought 70's CNC machines to life!! It's a block with holes in it. You can do it!
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: JCB 803 Saga
« Reply #46 on: July 03, 2015, 12:40:39 PM »
Steve, thanks for your confidence but it would be a last resort, as it would be quite a long term project, and meanwhile the digger sits unmovable, and I need to use it !

The day isn't getting any better - the chap in Wales has just rung back to say he has not got one  :(

There is a slim hope that a fellow in Southern Ireland may, but he's the chap who let me down before over the control valve
Andrew Mawson
East Sussex

Offline mattinker

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Re: JCB 803 Saga
« Reply #47 on: July 03, 2015, 12:45:44 PM »
Andrew,

Very bad news! Were is it broken? Is there no way you could stitch it like metal stitching in cast iron? A slot at right angles to the split, a tongue of Al with stainless screws coming in from the side to lock it in place, may be a bit of a mad idea, possibly in conjunction with low temp solder.

Can't you pre heat the whole block and TIG it?

All the best, Matthew

Offline awemawson

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Re: JCB 803 Saga
« Reply #48 on: July 03, 2015, 06:06:52 PM »
Matthew I'd be very wary of tigging or any other high temperature method unless I had a second block to fall back on. There are (seemingly) reamed bores in there for the various valves to seal onto that can easily be distorted, and I suspect seats for valves at the base of some bores.

Until the whole caboot  is stripped I cannot be sure exactly how things connect up in side. There is a 'main pressure release valve', a (logically) T shaped one way valve pair, and a bit I don't fully understand that changes the pressure setting dependant on how much oil is demanded from each of the three pump sections - I have the hydraulic diagram but translating it into physical reality isn't simple.

I want to try and set up my Gopro camera pointing at  it to see exactly where the oil emerges as once it starts everything gets covered and the forensic trail gets blurred  :bang:

It's been suggested that I could replicate it using standard hydraulic components 'off the shelf' but I have a feeling it's made as it is as it's operation is more subtle that that approach can achieve.
Andrew Mawson
East Sussex

Offline mattinker

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Re: JCB 803 Saga
« Reply #49 on: July 03, 2015, 06:23:32 PM »
Andrew,
I thought you'd got further into stripping than you have, so you don't actually know where it's leaking? OK, you don't need any more suggestions for the moment!

Good luck with pinpointing the leak, regards, Matthew