L4330 hydraulic problems

[hosejockey2002]

I'm posting this problem for my dad. He's in rural Montana and has an L4330 with a BH90 backhoe. This season when he remounted the backhoe, he noticed very slow and weak backhoe operation. The loader works fine, with no problems. He took the tractor into town for a local guy (nearest Kubota dealer is 100 miles away) to troubleshoot and all he has been able to find out is that the system hydraulic pressure is around 3000 psi (normal), while the power beyond port (which powers the backhoe) has only 500 psi. Has anyone had a similar problem, and if so what was the fix. Unfortunately I'm not in a position to check anything on the tractor, so I'm just looking for ideas, thanks. FWIW, the tractor has had filters and other maintenance done as required by Kubota. It has around 230 hours on it.

 

[rbargeron]

There's an outside chance this is a simple fix.

Not all loader control valves have the power-beyond function. PB is typically an added feature. A sleeve is installed that blocks the valve's open center, preventing supply flow going to the return/exhaust port. The power-beyond sleeve is usually installed from the outside. There are o-rings on it - and if the seal at the inner end fails the pressure would drop. (pic is a power-beyond sleeve for a Walvoil valve - not Kubota)

With the engine off look for a hex plug on the valve. If there is no separate plug, the PB sleeve may be in the port where the PB hose goes out (see the attached .pdf) Either way, inspect the o-ring at the inner end.

As always, prompt & cheerful refund if info is bogus. Dick B