jenkinsph
Super Star Member
I am in the dark without any drawings to look at. I have to ask a few questions to get a better idea of what is happening.
Is the engine loading down when you attempt to raise the hitch? Do the hydraulics squeal or hiss excessively?
If not it would indicate the piston seals on the rockshaft may be shot and fluid is passing around the piston. When you let off the control lever the piston would still hold its position if there are no leaks in the lines or external leaks on the rod seals.
If the engine does load down and you have already determined you have 1500-2500 psi pump pressure you may have restrictions in the flow path between the valve and the rockshaft cylinder. Since you did not mention any loading or squealing I tend to think this is not the problem.
Since you have pressure to the remotes in the correct pressure range I doubt the pressure relief is the problem. Usually you would have only one relief valve for the entire system at the end of the flow path and that would protect the upstream remote valve(s) and the rockshaft valve. When testing the remote with a pressure gauge at the 2500 psi you should be able to detect flow through the relief line returning to tank. I use a long screwdriver if needed and hold it on the line and put my ear to it to listen, may have to have a helper operate the remote lever for you.
A screwdriver or cheap stethoscope can be used to check other lines if these are exposed too. It would be good if you can check for flows through the rockshaft valve and the rockshaft cylinder lines too.
So far I am betting on the rock shaft cylinder piston seals are the problem.
Is the engine loading down when you attempt to raise the hitch? Do the hydraulics squeal or hiss excessively?
If not it would indicate the piston seals on the rockshaft may be shot and fluid is passing around the piston. When you let off the control lever the piston would still hold its position if there are no leaks in the lines or external leaks on the rod seals.
If the engine does load down and you have already determined you have 1500-2500 psi pump pressure you may have restrictions in the flow path between the valve and the rockshaft cylinder. Since you did not mention any loading or squealing I tend to think this is not the problem.
Since you have pressure to the remotes in the correct pressure range I doubt the pressure relief is the problem. Usually you would have only one relief valve for the entire system at the end of the flow path and that would protect the upstream remote valve(s) and the rockshaft valve. When testing the remote with a pressure gauge at the 2500 psi you should be able to detect flow through the relief line returning to tank. I use a long screwdriver if needed and hold it on the line and put my ear to it to listen, may have to have a helper operate the remote lever for you.
A screwdriver or cheap stethoscope can be used to check other lines if these are exposed too. It would be good if you can check for flows through the rockshaft valve and the rockshaft cylinder lines too.
So far I am betting on the rock shaft cylinder piston seals are the problem.