Good day Friends Please I'm having issues on John Deere Grader. There is a constant pressure present in a load sensing line, this keeps the pump overworking that it begins to heat. Constant flow from steering valve and both left and right direction control valve. I made some adjustment to flow-reducing-valve in the combination valve (hydraulic manifold) and steering valve became normal but the two control valve keeps producing pressure. I also check load sense relief valve, I can't make adjustment to it, nothing moves and I don't know how it works - if it's stucked. Machine plate number: DW770GX625066 Motor Grader Anyone experience this issue or help me with the hydraulic Schematic? please your contribution is well appreciated.
Try checking the system relief valve #11. It's only supposed to open if the standby pressure is too high to protect the pump and other components. If there's a bad o-ring or broken spring in it that could be causing the pump to stay in stroke. That will also cause an overheating issue. It's worth a try, hope this helps.
Th Thank you for your input I'll try it and give feedback. There is constant oil flow in load sense line - which should only be present if lever is in operation.
sincerely appreciate all the insights and support I received from the great minds in this forum. I’m truly glad to be part of this platform. My heartfelt thanks to everyone who took the time to respond to my post. I’m pleased to inform you that the issue has been resolved. For anyone who may encounter a similar problem, here are the steps I took: Connected a pressure gauge to the pump. Adjusted the pressure reducing valve. Observed the pressure drop from 1500 psi to 500 psi (system operating pressure was initially 1500 psi). Adjusted the load-sense relief valve until it reached 2000 psi max operating pressure. The machine is now operating perfectly. However, I’m still curious about why Deere incorporated a load-sense relief valve into the system, as the adjustments above seemed to function similarly to tuning the load-sense and pressure compensator spool. Thank you all once again.