Hi, I have a Komatsu PC220-7 excavator Japanese made year 2009. Recently, it started acting up. The right track along with arm in was slow and the hydraulic is overheating. It also had an issue of breaking hydraulic cooler when working on hydraulic hammer. I did a lot of things such as replacing hydraulic pump, relief valves, LS & unload valve resealing control valve, replacing 2 solenoid on the solenoid valve, resealing swivel joint, resealed some compensation valves etc. Today I replaced parts in the weak track motor. Now that track is strong but the left track which was strong became weak for some reason. I have also noticed something strange in the monitor. When I pull track stick of the weak side the oil pressure switch on the other side of the merge-divide valve of the main control valve reads 20 bars escaping to it while the stronger track shows only 4 to 5 bars escaping to the other side of merge-divide valve. Any suggestion why the stronger track became weak after replacing the right track motor which was weak in the first place and why is the machine breaking hydraulic cooler. In addition, is the 20 bars escaping to other side of merge-divide valve. Thanks
Confused by what you've stated, but... If operating one track creates a pressure rise in the other, then the rotary joint (swivel) seals are suspect. You didnt say how many hours?
As for the hydraulic cooler failing while operating a hammer, I've had to add a low pressure accumulator to the return side plumbing to lessen the hydraulic shock making it's way to the cooler.
Done the resealing for the joint recently. They are brand new. Replaced the accumulator a month ago. I got a tech from komatsu and he adjusted the pedal for the hammer line. He said that the pedal was pushing piston way too down which was creating too much pressure keeping in mind that on this machine there is no flow solenoid under the pedal so it has to be adjusted manually. I personally dont buy that comment but didnt test the machine yet after that. But one thing surely happened with the adjustment is the machine no more vibrates like before.
The machine is around 23000 hours