JCB Backhoe Valve Sticking Badly

[Delmer]

Yep, looks like that's not gonna hone out. If you can't find a new cylinder, a machine shop can build you a new piston, and weld a new cylinder tube onto your re used end.

If you were desperate, that cylinder and piston could be fixed, but probably not worth the time and new seals.

The valves might still be salvageable by honing.

 

[Tinkerer]

Some more.

Yikes !!
I'm glad that you found the problem.
If you choose to repair it, try to get a price from more than one hydraulic shop if that is possible.

 

[Piston]

Today I refiltered the hydraulic fluid through a 7 micron filter, cleaned the suction strainer as best I could, buttoned everything up, and then filled the hydraulic tank with the filtered fluid.
I contacted a hydraulic shop who will give me an estimate on repair or replacement of my cylinder. They sent someone today to pick up my cylinder for assessment. I should hear back in a week or so with an estimate.

in the meantime, I will see about honing out the backhoe valve block.

At this point my dipperstick cylinder is at the shop. The hoses are obviously open to the atmosphere with no plugs. I plan to at least wrap them in plastic to avoid any contamination getting to the system. Mia there any reason I can’t still use the machine at this time???? Obviously can’t use the backhoe, but I don’t see why I can’t use the loader bucket?

I’d like to use the machine for an hour or two and then completely drain and refill all the fluid again. Rinse and repeat.

 

[Tinkerer]

If the problematic spool for that cylinder is leaking, the cylinder lines will need to be capped.

 

[Piston]

I tried moving it but as soon as I started it the fluid started pouring out the lines. I’ll keep it where is for now. It’s very likely the spool isn’t even in the right position to begin with, so removing that will be the next step.

 

[Piston]

Im in need of a parts manual or a source to look up part numbers.

Slight update….I was able to hone out the bore of the sticking valve spool section. I lightly sanded a couple bumps in the spool itself as well.

After reassembly the valve spool now moves up and down relatively smoothly except for one spot, which has the slightest “detent” that I can ever so slightly feel an imperfection. Before, I couldn’t move it at all unless I tapped on the spool with a rubber mallet.

I left it as is because I don’t want to hone it out anymore until I’m able to start the machine up and test it out, in fear of honing it TOO much.

Im still waiting on the estimate from a hydraulic shop for the dipper cylinder. In the meantime I’m searching for a used cylinder. My JCB dealer said they discontinued that part number so I can’t buy one new even if I wanted to.


While I wait id like to order some other small dollar parts I could use. Does anyone know where I can get a parts manual before I buy a random downloadable one online?

 

[Tinkerer]

A serial number is need to determine which manual is applicable to any particular machine.
There are printed manuals available on ebay.

 

[skata]

You can find used parts here.
Use the filter function to sort by model.
https://www.machinerytrader.com/listings/search?Manufacturer=JCB&Condition=DISMANTLED

 

[Piston]

I’m hoping the next update will include photos of a working backhoe. I’m cautiously optimistic.

I finally got the estimate to repair my cylinder, $2,875.
I found another cylinder (used) which I’ll purchase as long as it checks out.

 

[Piston]

I bought a couple plugs for the backhoe hoses that go to the missing cylinder. I fired it up and played around with it a bit.

I was impressed with how easily it filled the bucket when driving into a virgin hillside! I enjoyed driving it around the woods a bit and found it maneuverable for such a big/long machine.

The first bucket was satisfying!




The cylinder that I wanted to buy didn’t pan out (it was also damaged). I think I’ll have this one repaired.

 

[stinky64]

That is a badass machine, hope ya get it sorted. If nothing else that will be a snow pushing BEAST.