I am working on a S60XM that is only developing peak 1500psi then drops to 1100psi at the test port at the control valve. I have tried adjusting the inlet and the outlet pressure relief valves. With no change in pressure. I took the control & presssure valves apart, cleaned them up and replaced the seals. No change but the pressure will adjust from 0psi to 1500psi peak out then it is still dropping to 1100psi. The motor acts like it is still under a heavy load after the hydraulics are run to bypass. I am afraid that the pump is the culprit but am trying to avoid this expensive repair. Any Ideas the group may have would be very helpful.
Showing items 1 - 9 of 9 results.
dia duit
sorry i forgot to say after stripping orbital unit found outside spool small holes at bottom blocked with debris from spring a full dismantling job required
good luck
and remember old mechanics never die just stop to recharge there batteries
Dia duit
just had same probelm put a test guage on main hydraulic pump 7/16 unf you should only have about 400psi 20 bar stand by pressure I found my probelm was a broken spring in the small brass check valve on the feed pipe into steering orbital unit and unfortunately it got inside orbital steering unit and partially blocked return to tank which caused hydraulics to overheat after taking over for half hour or so or sooner if driven I hope this helps someone cause it took a long time to find slan go foil from ireland
priority valve could be stuck open but going by the hours i would reckon the pump needs replaced
Oh yeah this unit is a 96 with a GM 3.0 and has about 9000 hours on it. I suppose I just need to bite the bullet, pull the pump and tear it apart to see what gives. I just was hopeing for a quicker and cheaper (for the customer) repair. Any Info on the priority valve would be great. Hopefully thats all it is, I can replace the priority valve o-rings and get them back up and running.
How would the steering priority valve cause the pump to loose suction. I am asking because I haven't as of yet had to repair one and if I tear into it I would like to know what to look for. The Suction hose is not colapsing and there is no air in the hydrailic fluid. The unit has about 1500 max PSI. But what gets me is that this unit was just fine 2 weeks ago when I did a PM on it and had to move some heavy pallets with it to make room to work. Now it hasn't enough to lift much of anything like something is bypassing the control valve. I thought the steering priority valve just kept fluid moving to the steer orbital
what age of truck?? how many hours??have you checked the steering priority valve ??
definitely check the above remarks, my money is on the hyd suction filter plugged or the pump itself is faulty
take a good close look at the suction hose and make sure it is not collapsing too.
when you remove the hyd tank cover (with the hyd running) do you hear bubbles?
Forkliftaction accepts no responsibility for forum content and requires forum participants to adhere to our rules of conduct. Click here for more information.
If you are having trouble using the Discussion Forums, please contact us for help.