I have a Lull 844B telehandler that doesn't have any boom, fork, frame, or carriage hydraulic functions. It does steer and brake. I show around 200 psi on the main pump test port. I had just replaced several blown seals in the pump but still no functions. I searched through the parts manual and found relief valves at the input of both valve blocks. I took them apart and replaced a bad o-ring in each. I have no oil returning to the tank from the rear 4-valve block and lots of oil returning to the tank from the front 2-valve block. Does this mean the relief valve on the front valve block has to be bad? It looks ok to me and I hate throwing parts at something and hoping it works. Could something else be causing my problems? Any input would be appreciated.
If your showing 200 psi direct on the pump test port. You got a pump issue right away. Relief valves stuck open or not, one maybe.. Two probably not since they are on separate circuits. Pull your pump and have it bench tested. I would say that is your problem.