kobelco sk 120 mark v long arm this machine repaired cobelco agent, these are they have done. main hydraulics pump overhaul pilot pump change pump proportional solenoid change all filters & hyd oil change pressure relief valve change but still machine is not OK. :Banghead:Banghead:Banghead:Banghead both tracks is OK. ( relief pressure 350bar ) boom is not OK. ( relief pressure approximately 170bar ) arm is not OK. ( relief pressure approximately 180bar ) bucket is not OK. ( relief pressure approximately 190bar ) swim is not OK. ( relief pressure approximately 180bar ) when backup switch is on no condition change (no pressure go up ) repair persons said valve box has a internal leak i think all port valve is OK. dear all my group any idea do you have for this ? thanks in advance
no one have idea for this can it be travel straight valve because only travel is good
know all that's problem is spool leakage
The straight travel valve only dedicates pump flow so that one pump supplies the tracks and the other supplies the working hydraulics. Your problem is most likely a leak internal to the MCV. What happens when you operate 2 functions at the same time such as arm in and boom up?
thanks for advice Mr ben witter operate 2 functions at same time machine change little slow bucket & arm operate individually i show the display p1 or p2 bypass cut proportional vale readings not change. low pressure sensor readings ok when i tried to do 'A' adjustment display shows 'CPU condition error' this is a machine serial no lp 13684 i want check CPU serial no and machine serial no is mach. can i know correct cpu serial no on this machine?
Ben Witter I have a 1993 Kobelco SK120 #LP-07713 All functions are working however they are slow. However when you walk the machine and slightly engage lift on boom or swing or anything the machine speeds up not just the tracks but everything. Also just digging if you apply slight pressure to the tracks not enough to engage the digging speeds up again. I have tested the pilot pressure at port P3 and get 500 psi all the time, I dead headed the boom and got 4500psi from port A1, i put the bucket against the track and got it up to 3000 psi from A2 before i stopped. I have removed both solenoids on the pump and they seem to be in working order, i also increased the Master relief valve by tightening it 2 turns slight change. I have also changed the filters checked the screen but it still almost lurches forward when both tracks and digging are engaged. Any thoughts or places to start would be greatly appreciated!
Hello, have you figured out your problem? Wondering as i have same issue