Backhoe Kubota 4560 backhoe boom will not rise

[Airdriver]

Found .pdf on how to build a press gauge from NAPA parts. Not clear though, where to break open the closed system of this backhoe as there are no quick disconnects and no obvious ports.
Looking to find the RV. Again, not obvious.
Could not find any contamination in fluid or filter.
Many thanks for the suggestions!

 

[bumperm]

The hydraulic pump and system is one big loop (with sometimes a secondary system to run power steering). So you can check system pressure at the loader valve, or? If you have a front loader with quick connects, disconnect one hose going to a loader cylinder/s and connect your pressure gauge there. can be either dead heading the line or T'd into the line. If T'd in, run that cylinder/s to it's limit and read max pressure which will be determined by relief valve.

 

[Airdriver]

Thank you, but this system is separate from the tractor system. There is no hydraulic connection between the backhoe and the tractor.

Backhoe is a discrete, closed unit with its own pto operated pump, filter and fluid resevoir.

 

[Grandad4]

Thank you, but this system is separate from the tractor system. There is no hydraulic connection between the backhoe and the tractor.

Backhoe is a discrete, closed unit with its own pto operated pump, filter and fluid resevoir.

There is a smaller supply line and a larger return line connected to the pto pump. Adding a pressure gauge in the supply line someplace between the pump and the control block should tell you a lot about what is going on. Since the flexible line from the pump connects to the bh with threaded fittings, that would be an easy place to put the gauge.

 

[bumperm]

Thank you, but this system is separate from the tractor system. There is no hydraulic connection between the backhoe and the tractor.

Backhoe is a discrete, closed unit with its own pto operated pump, filter and fluid resevoir.

Okay, sorry I missed that - and you clearly stated in the first post. Age.

As others have suggested, a pressure gauge is handy, and inexpensive to add to the hoe.

Do the other functions work with authority, i.e. will the stabilizers start to lift the rig? If so, then the problem is most likely the control valve spool. Inspect the spool physically to be sure the mechanical linkage is not worn and that the control stick moves the valve spool through its entire range of motion. Disassemble the spool valve (it's easy).

If the stabilizers will not lift as expected, problem is most likely the PTO pump. If you can discern model, most have overhaul kits available. A new PTO pump is also an option, check ebay and the discount, surplus hydraulic places online.