Howdy, My 1992/3 Link Belt LS 2700 Series II developed an issue recently after sitting unused for about 2 months. All controls function normally except for the stick. The stick has limited power and movement is considerable slower than prior to this issue. If I operate the stick and try to track at the same time, the machine will stop moving and the stick will move very slowly. The machine is JD control configuration. If stick out all the way and bring it back toward the machine, there is no positive hydraulic pressure to swing the stick back towards the machine (seems like the stick is just moving via gravity or idle pump force) until it gets to a point where the pump applies pressure to bring the stick full back. If I put the stick to use during a dig and try to stick in, the stick will have limited power then stall, then power through the motion very slowly or will stall completely depending on how hard the ground is that I am working. Almost like the system has air in to or is cushioned. I check pump pressures at both ports and get 3800 psi. Oil level is good. Cleaned return screen and replaced hydraulic filter. Any help/advice would be greatly appreciated. Thank you
Pressure test every function on the boom and slew and log the results. If the pressures are all over the place then it's most likely the 0 rings in the control blocks need replacing. If the pressures are constant on each block but not up to spec then the pressure relief valves require some attention which maybe just 0 rings.
Thank you, Tones. I check the pressures. I was thinking that it could be a broken relief valve spring or O rings. Or maybe a seal in the rotating swivel valve.
A leaking rotating swivel shouldn't affect the bucket functions in my experience just the track drive only. Failed 0 rings in the control block can effect the track drive though. Testing is cheaper than guessing, just keep that front and centre and you'll find the problem. Good luck
Thanks again.
Testing the pilot pressures, I have 400 psi at the test port but only about 150 at the lines going into the spools.
Log in www.autorepairmanuals.ws I don't anything about this outfit but it may help Have you tested any of the main function circuit's yet?