I have a PC450LC-7 Komatsu excavator that is doing some strange stuff. first of all a few weeks ago the hydraulics become weak and if I operated more then 1 function at a time it would stop all together. at the same time the RHS track was operating extremely slowly and would not even move the machine. during the testing procedure about 4 hrs in, it cleared itself and away it went like a bat out of hell. everything was back to normal. the day before yesterday the same problem but not exactly the same. the hydraulics lost power again only this time it was the LHS track operating extremely slow. this was late in the afternoon so I left it until yesterday to test. when I got to the machine the hydraulics for the boom and bucket were back to normal but the track was still weak. I tested all the pump, LS, PC, LS EPC ,PC EPC pressures and all showed up ok except the LHS track. when I operated the control in the cab I would only get 1100psi oil pressure at the signal line into the servo piston on the pump and 1100psi pump delivery. when I operated the boom up function with the pressure gauges in the same ports I would get the correct operating pressures so I ruled out the servo piston being stuck and not stroking up the pump. about 12 hrs into testing I noticed rain was coming and attempted to move the machine from the creek bed I was working in. during the procedure to move the machine, bang, it came good again and has not missed a beat. it has me stumped, has any one else had a problem similar to this?
floating piece of FOD in the pilot control?
sounds like a safety hanging up, had that twice
Is that the safety in the travel motor? Would it effect the operation of the other hydraulics? What were your symptoms?
in control valve, boom wont lift up with stick at 90 degrees empty bucket 60".. no relief prressure on one track one dircetion. boom would be fine is bucket was over relief