Kubota L4400 hydraulic and FEL failure

[HydrauHustl]

I recently bought a Kubota L4400 with only 151 hours, but it has sat idle for a long time. the FEL is completely unresponsive, it won't lift or tilt. and while the 3point hitch eventually raised after adjusting the flow valve, it drops painfully slowly
since the power steering works, the pump seems functional, but the hydraulic fluid I drained was dark and severely degraded.
despite changing the fluid and filters, the issues persist. I’ve verified oil flow at the joystick block and quick couplers, and I even cleaned a rusted spring within the joystick assembly
when I move the lever, the hoses vibrate, and the bucket may nudge an inch, but it lacks any real power. I’ve cracked the lines at the cylinders and confirmed there is pressure, yet the system refuses to actuate
I’m new to hydraulics and am stuck. Could an internal blockage or a faulty relief valve be the culprit after the machine sat for so long?

need advice on how to test the pump pressure or identify what I might have missed in the joystick or block assembly.

 

[Cooperhawk]

Above my pay grade but I'll be watching.

 

[Axon]

Had a similar nightmare with an old loader that had been sitting around forever.
It turned out to be a stuck relief valve that was dumping pressure back into the tank.
Doing a gauge test at the pump really helped clear things up for me.
Sometimes those hydraulics can be working hard just not in the way you think.

 

[Quanta]

Sounds all too familiar. Spent ages chasing filters, hoses, and even cylinders, only to discover that a clogged suction screen was the real culprit starving the pump. Always start with a pressure test before hunting for hidden blockages. These tractors have a knack for hiding problems where you’d least expect them.

 

[Mimos4]

and while the 3point hitch eventually raised after adjusting the flow valve, it drops painfully slowly

as far as I know, on Kubotas, the hydraulic flow usually goes from the pump to the FEL Valve to the 3 Point Hitch

if your 3 point hitch lever is stuck in the up position or the feedback rod is out of adjustment, it can keep the system in a constant state of bypass, which starves the loader of pressure. try lowering the 3 point arms completely and see if the loader suddenly wakes up

 

[Alan]

Makes total sense. Never thought about the bypass starving the loader like that. Thanks for the insight.