JCB 8018 dipper issue

[Muz]

Not had a chance to check track speed or spool valve for scratches/issues. I intend doing both tonight and will post an update tomorrow.

In the meantime I priced up the o-rings and according to JCB dealer I can't get them individually and need to buy a valve block seal kit at over £300. That's a bit pricey for potentially one dodgy seal! Does anyone know of any other suppliers I could maybe contact.

Would be best to stick to JCB, but dont worry about that just yet, might be a spool rod that sorts it, without stripping anything ..

*edit* fook me .. that is expensive .. will be a good few rings in it I suppose ... special JCB quality rubber

[vfr98]

I got some time on it last night. Few things:

1. spool rod was fine - came out pretty easily and looked to be in good condition, and went back in just as easily

2. LH track does move quicker than RH track when both are at maximum. If I remember back, I think I've always had a slight difference in speeds. Never seemed to get in the way though. Is there a reason why this might be important?

3. I took the plunge and removed the whole block again, but have not yet split it. Going to do that tonight (and carefully).

[Muz]

when you tested the pump, was it a pressure test ?, and did you check the pilots were moving ok ?

[Mick-the-fitter]

I got some time on it last night. Few things:

1. spool rod was fine - came out pretty easily and looked to be in good condition, and went back in just as easily

2. LH track does move quicker than RH track when both are at maximum. If I remember back, I think I've always had a slight difference in speeds. Never seemed to get in the way though. Is there a reason why this might be important?

3. I took the plunge and removed the whole block again, but have not yet split it. Going to do that tonight (and carefully).

Normally each track is supplied by a different pump or oil supply, with an individual relief valve, therefore different services are also supplied from different pump or oil supply! Can you tell me does your machine have gear pumps bolted together (3) or a swash pump with pilot? If one of the gear pumps is worn or damaged then less or no oil will feed one side of the spool valve, unless in your case you dead end a circuit fed by the good pump, in which case high pressure will feed the dipper rather than push past the main relief. Quick check (with the spool block in) change the pipes over on the pumps and see what works and what doesn't!

The he reason the tracks still work is there is a built in straight track valve, which supplies equal oil to each track, if one pump is not working then it will track using the oil it has.

Mick

[vfr98]

Hi Mick/Muz

The dipper and all services are now working fine. We may need to tag this post under the scottish term "ya fud".

When I split the valve block last night I took my time looking at the dipper slice. This was the one that had 2 o-rings seated on either side. I also took out the spool rod and checked it over again. Everything looked fine and when I put it back together again I kept a close eye on the service manual and something didn't seem right. The upshot is that this slice, unlike others, is very similar looking whether it is upside down or back to front. You can see where I'm going with this....

When I split the block last time I've inadvertantly flipped this dipper slice. This created a block from the track side and opened up an inlet on the aux side. This explains why, when aux was maxed oil could get into the dipper, but when I tried to use the dipper on it's own the oil had no-where to go and was vented through the MRV on the track slice.

I took photos before I took it out first time and before I took it out the 2nd time. When I look closely I can see the bolts on the relief valves are different, confirming I did indeed put it back in upside down. Hence, the term, I'm a fud.

I put it all back together again last night and other than some cosmetic stuff I'm going to sort it out, all seems well.

For anyone reading this and looking for lessons learned. I'd say:

- use coloured zip ties and a system to mark all hoses before you take them off. I initially used silver gaffa and a permanent marker but quickly realised hydraulic oil and permanent markers don't work
- take loads of photos as you go - pain in the backside with oily hands/gloves, but worth it, as long as you check when you put it back together again (ahem!)
- mark valve slices as top or bottom (I've since noticed very worn out tippex on the top of my valve block which suggests someon'e done it before me)

Thanks to Mike and Muz for your help. I know this was self inflicted but the troubleshooting around it has been really useful and I do understand a lot more about how it works.

Cheers
Scott

[ianoz]

Good you got it sorted Mate ..

[Muz]

Thanks for posting the thread Scott . Forums can be useful resources, made more so by input such as yours, and all the more gratifying to get to the bottom of the problem without any relative expense too. Coloured bag ties are very useful for these projects indeed Happy digging

[Mick-the-fitter]

Hi Mick/Muz

The dipper and all services are now working fine. We may need to tag this post under the scottish term "ya fud".

When I split the valve block last night I took my time looking at the dipper slice. This was the one that had 2 o-rings seated on either side. I also took out the spool rod and checked it over again. Everything looked fine and when I put it back together again I kept a close eye on the service manual and something didn't seem right. The upshot is that this slice, unlike others, is very similar looking whether it is upside down or back to front. You can see where I'm going with this....

When I split the block last time I've inadvertantly flipped this dipper slice. This created a block from the track side and opened up an inlet on the aux side. This explains why, when aux was maxed oil could get into the dipper, but when I tried to use the dipper on it's own the oil had no-where to go and was vented through the MRV on the track slice.

I took photos before I took it out first time and before I took it out the 2nd time. When I look closely I can see the bolts on the relief valves are different, confirming I did indeed put it back in upside down. Hence, the term, I'm a fud.

I put it all back together again last night and other than some cosmetic stuff I'm going to sort it out, all seems well.

For anyone reading this and looking for lessons learned. I'd say:

- use coloured zip ties and a system to mark all hoses before you take them off. I initially used silver gaffa and a permanent marker but quickly realised hydraulic oil and permanent markers don't work
- take loads of photos as you go - pain in the backside with oily hands/gloves, but worth it, as long as you check when you put it back together again (ahem!)
- mark valve slices as top or bottom (I've since noticed very worn out tippex on the top of my valve block which suggests someon'e done it before me)

Thanks to Mike and Muz for your help. I know this was self inflicted but the troubleshooting around it has been really useful and I do understand a lot more about how it works.

Cheers
Scott

Hi Scott, glad to be of assistance, there are ways of diagnosing things by asking questions, taking photos, and cable ties are great for jobs like yours, used them in the past, also for future reference cable ties are numbered near the ratchet end.

Well done, good to know you are back up and running.

Mick