JCB and my JCB 803 Driving Me Mad !

[AndrewMawson]

About a month ago I acquired a 1997 JCB 803, it had it's good points like a pretty well new replacement engine, all the glass in the cab, and not been tarted up with paint, but it had a big leak from the rotary hydraulic seal unit that joins the cab / engine to the track unit.

Needed a replacement seal kit fitting - a fiddly job in a tight spot under the floor. I'm too long in the tooth to be crawling about in on and under, so I sent it to a local(ish) commercial garage who have a good hydraulic fitter I'd used before when I had a 3CX.

Seal kit ordered up from JCB, duly fitted and failed to cure the leak

At huge expense agreed to order up an entire replacement rotary seal unit, turns out there's been a design change and although the replacement will fit, it needs a 'fitting kit' as apparently the ports are in slightly different places.

Current situation - commercial garage physically has the rotary seal, but JCB cannot find details of what the fitting kit comprises

Meanwhile I'm going backwards and forwards (on phone) between Greenshields JCB Burgess Hill and John Jempsons in Rye trying to find a solution without success


I wouldn't have thought that it's rocket science - 8 ports above (left track motor =2, right track motor =2, motor fast/slow =2, and dozer ram =2) - need connecting to 8 ports below. The track motor speed control is small bore (1/4" ?) and all the rest are bigger (1/2" ?) and so long as you don't try putting a big pipe on a small port it shouldn't matter which are used so long as the upper corresponds to the lower - but maybe there's more subtlety to it than I think ?

[Muz]

About a month ago I acquired a 1997 JCB 803, it had it's good points like a pretty well new replacement engine, all the glass in the cab, and not been tarted up with paint, but it had a big leak from the rotary hydraulic seal unit that joins the cab / engine to the track unit.

Needed a replacement seal kit fitting - a fiddly job in a tight spot under the floor. I'm too long in the tooth to be crawling about in on and under, so I sent it to a local(ish) commercial garage who have a good hydraulic fitter I'd used before when I had a 3CX.

Seal kit ordered up from JCB, duly fitted and failed to cure the leak

At huge expense agreed to order up an entire replacement rotary seal unit, turns out there's been a design change and although the replacement will fit, it needs a 'fitting kit' as apparently the ports are in slightly different places.

Current situation - commercial garage physically has the rotary seal, but JCB cannot find details of what the fitting kit comprises

Meanwhile I'm going backwards and forwards (on phone) between Greenshields JCB Burgess Hill and John Jempsons in Rye trying to find a solution without success


I wouldn't have thought that it's rocket science - 8 ports above (left track motor =2, right track motor =2, motor fast/slow =2, and dozer ram =2) - need connecting to 8 ports below. The track motor speed control is small bore (1/4" ?) and all the rest are bigger (1/2" ?) and so long as you don't try putting a big pipe on a small port it shouldn't matter which are used so long as the upper corresponds to the lower - but maybe there's more subtlety to it than I think ?

They might say the ports are in different places, but what that may mean is the mounts may therefor impinge on hose routings if plonked straight in, or the mounts are different themselves, hard to know without seeing it, but you are right in that the plumbing shouldnt be so hard ? you can get various adapters to change pipe directions and angles etc. I take it the centre distributer must have been too worn to re seal ? in which case you would have thought you could have replaced that and still used the old body ?

[AndrewMawson]

They might say the ports are in different places, but what that may mean is the mounts may therefor impinge on hose routings if plonked straight in, or the mounts are different themselves, hard to know without seeing it, but you are right in that the plumbing shouldnt be so hard ? you can get various adapters to change pipe directions and angles etc. I take it the centre distributer must have been too worn to re seal ? in which case you would have thought you could have replaced that and still used the old body ?

Seems they discontinued that model When I saw the dismantled 'male' part that the seals and 'o' rings rub on it seemed ok. If I was doing the job myself I'd polish the male part to a fine finish and try again, but that's the frustration of putting things in others hands - sadly often a necessity these days.for me

[Muz]

Hmm .. thats odd .. so could you see where the oil was coming from ? I assume just dripping from the bottom ? (kinda academic now I know... just I'm curious) Sometimes theres a certain amount of pressure required to join the valve back together, and too much can rupture a poorly fitted seal, its a bit of a touch and go job, to reassemble some of them

[AndrewMawson]

Out from the top of the unit where the male (upper) enters the female (lower). From there it drips down into the frame members and out by the track gearbox. Thought at first it was the track motor

[Muz]

I see .. rekon they pinched a seal when reassembling then .. especially if you rekon there wasnt any wear on the center pin ? Might also have got the order wrong .. cos its a lot of rings normally . Normally you can only copy what comes out, with what goes in and its real easy to get mixed up, no seal kit Ive seen had any instructions or order !

[Muz]

Also .. I see the problem with the hoses now, is that some entry/exits are on the same level as the bottom tray, so its cut out, to accept hose routings, where the new unit wont fit .. that is crap that JCB cant supply a unit to fit your machine ?

[AndrewMawson]

The drawing I have is from an 803 plus (mine's not a plus) and it only shows an upper and lower lip seal which both face as you'd expect towards the pressure, then 'O' rings separating the various levels - so not too complicated. But it's easy sitting in my arm chair with clean hands to criticise the poor fellow with skinnned knuckles and a crick in his neck who's actually had to get at it to do it

[Mick-the-fitter]

The drawing I have is from an 803 plus (mine's not a plus) and it only shows an upper and lower lip seal which both face as you'd expect towards the pressure, then 'O' rings separating the various levels - so not too complicated. But it's easy sitting in my arm chair with clean hands to criticise the poor fellow with skinnned knuckles and a crick in his neck who's actually had to get at it to do it

Hi Muz, hi Andrew, let me have details of the machine, the serial number and I will see what I can come up with, the seals I think are one O ring and two backing rings per groove, hard to get all in correctly, have done them in the past ok but, need to be careful.

Initially i I can't see why the male part would be that worn unless there is corrosion or damage from some thing other than oil, and a resell should sort out the problem!

Mick

[AndrewMawson]

Hi Mick,

M/c number is 0765124 but I'm being told that the rotary coupling fitted doesn't match what JCB think should have been fitted originally

[v8druid]

what do you expect? ........... it's a JCB
Surpassed only by Land rover in the "we have no idea what we fitted that day - could've been anything" stakes

[Muz]

Couple of tips for fitting / re assembly . The 'o' rings arent usually a problem but because the valve is so long, getting the nylon ones in the right place can be a pain, but if you put them in a pan of warm water first it softens them and makes them easier to work with. Poking them in with screw drivers can damage them, try to use some blunt plastic 'poker' to do it. Once they are all in, I lube the surface of the valve body not the centre pin, that way it meets lube all the way as it gets re fitted

This of course depends in whether you are past this stage or are just going to fit the new valve and would mean buying a new set of seals

[Mick-the-fitter]

Hi Mick,

M/c number is 0765124 but I'm being told that the rotary coupling fitted doesn't match what JCB think should have been fitted originally

Hi Andrew,

It seems that your old rotary joint45/910000 and seal kit 45/910010 has been superseded with

A new rotary joint 45/914500 and seal kit 45/914515 but conversion kit for it consisting of some fitting blocks and nuts and bolts, is no longer sold.

Aparently the the new rotary joint will fit, no other information is available.

Mick

[AndrewMawson]

Mick thanks for that.

From that is it correct to assume the fitting blocks adjust the vertical position of the unit hence needing ?? longer ?? bolts and that the hydraulics should fit as is?

Do you have any illustrations from your source ? Any further information would be VERY welcome as this is getting rather silly at the moment ?

Many thanks for your researches so far

[Mick-the-fitter]

Mick thanks for that.

From that is it correct to assume the fitting blocks adjust the vertical position of the unit hence needing ?? longer ?? bolts and that the hydraulics should fit as is?

Do you have any illustrations from your source ? Any further information would be VERY welcome as this is getting rather silly at the moment ?

Many thanks for your researches so far

Something else that that I noted was on the early rotary joint both outer and inner parts were available separately, but on the later it's a unit! From an engineering point of view, maybe it points to the fact that they were not a very good machine fit and leaked by design! I will see what is available as far as drawings or such like material.

Mick