Hydraulic speed?

Kubota27 · Jun 15, 2009

What governs the speed of the hydraulics? For example, my FEL roll is pretty slow, regardless of engine speed. It used to be faster, then just got slow one day years ago. My tractor is a Kubota L2250, about 20 years old, with 1000 hrs. The THD fluid level shows just at the top line in the sight glass. The FEL is not a Kubota, I think it's a Great Bend. I borrowed my neighbor's new Kubota 5400 series and was amazed at how responsive the FEL is both in up/down and roll.

Additionally--and I don't know if this is related or not--but very recently, and infrequently, the FEL will intermittently not want to go up. It will move extremely slowly, although if I drop the throttle to idle it will move quickly, loaded or empty. Then it will be ok. If I pump the valve, the valve will sort of rattle like it's under tremendous pressure when I just crack it open. Then the problem will go away. To me, it's a mystery.

Thanks for any help here.

DIXIEDOG · Jun 15, 2009

Speed is generally controlled by flow velocity. The higher the GPM for a given hydraulic system the faster it will move.

GuglioLS · Jun 17, 2009

Several possibilities -

1. The Spool and or valve body is worn or scratched allowing fluid to partially blow past the valve.

2. The PR (Pressure Relief) in the valve is sticking and or partially open.

3. The pump is worn out so it's not providing full flow or pressure.

4. O-rings in the cylinders are worn, allowing fluid to pass from one side into the other.

5. Clogged suction strainer.

6. Air getting sucked in the suction side.

7. Combination of some or all of the above.

With 20 years and 1000 hours, most likely something has worn out. My guess is the pump. But it could be the PR valve. Start with the simple stuff.

Have you pressure tested the system?

Larry