AC 190 hydraulic’s

My buddy has a early 190 diesel. Power steering and transmission/PD work great but it will only slowly lift his bush hog that has a single hose Ram. Same issue with his V-rake. The screen at the pump manifold had been removed before he bought it. He drained the hydraulic fluid and found no screen in the sump thinking it may have been updated with a screen there. Ordered a new screen, gasket, filter, and replaced with new hydraulic fluid. We also removed the spring and piston in the pump manifold to make sure it wasn’t stuck. Previous owner had added a small nut on top of the spring to increase pressure. Other than that, the piston looked fine and was not sticking. There is only 1,400 psi at the remotes instead of 2,000. Am I missing something else or is it time for a pump rebuild?

Edited by AC720Man - 23 Jun 2023 at 11:41am

Remote couplers on tractor worn out?

An update, my mistake. Bush hog is 3 pt, it will barely lift it off the ground. V-rake uses remotes, works very slowly at 2,200 rpm. I misunderstood what he was lifting. Regardless neither hydraulic system is working well.

Edited by AC720Man - 23 Jun 2023 at 2:36pm

70276323 Is the new seal kit number doc is taking about. Still available

Rebuilt the relief valve this morning and it definitely needed it. O-rings were hard and for sure were not sealing very well. Ordered the over priced kit. Surely we found the source of the issue we hoped. It helped some but no were near factory specs. Steering and power director work well but hydraulics are still below par. Gauges on the remotes verify it’s still not good. So, unless there is something else to try it sounds like a pump rebuild is next?

I just wanted to make sure you tried adjusting the relief valve pressure.  Our One Ninety was bought new by my parents.  After about 40 years the adjusting screw backed out and it suddenly lost the ability to lift a haybine.  I recall it didn't even take one full turn to get it back to spec.