I recently purchased a komatsu pc100L-6. I have rebuilt the engine since purchased but now I can run it until the oil warms up (2-3 hours) and the hydraulics get slow and seem week. I have replaced the hydraulic filter. Once the oil is hot it has no power in the tracks, swing is always week but gets worse. I realize it may need a pump rebuild but is there any valve that could be wore out or something else to check before I rebuild the pump. Thanks
First thing - check the pilot pressure!
Where would the access point to check pilot pressure? I apologize but this is all new to me. The pilot pressure it used by the controls to control all main functions correct? I bought a gauge kit just for this but I haven’t used it yet cause I didn’t know what to check really.
Never worked on Komatsu, but trace the hose from smallest pump out of three to a filter, on most machines the quick connect is either on filter housing or manifold block housing. You gonna need Komatsu/Hitachi type of snap connector to do that. The one for CAT,Case,Deere will not work.
Ok thank you I’ll look into it
You might wanna check the pilot pressure right at the spool actuators of functions that are in question and see the pilot pressure drop there, in case actuators them selves leak and do not move spool fully! It might not show up on Pilot circuit pressure readings! You gonna need special Komatsu Run Tee gauge port fittings for that! You can find them on EBay!
Good day Question is did the machine have the problem before you rebuilt the engine ? Kind regards Uffex
It wasn’t doing it before and I ran it about 100 hours after rebuild before it started doing it
Good day CI If this problem appeared after the engine rebuild I would suggest to double check all the work you have made - fuel system - induction ect. Take a close look at the exhaust see what kind of smoke and smell it has under load. Kind regards Uffex
Good point Uffex! Very often engine performance issues are misunderstood as “slow Hydraulics”!
Check the strainer in the banjo bolt on the suction side of the hand priming pump before you even think about anything hydraulic. You also might drain the sump on the fuel tank and check for a fuel water strainer that came in a lot of gray market machines. Air filters are another issue and yours originally came without the secondary air filter that goes inside the main air filter. If the engine checks out OK, there were lots of hydraulic issues with those machines when they first started showing up in the US and Komatsu would not share any information. You will need to post some photos of the pump. One from the back and one each on each side. A photo of the front and sides of the control valve will also be necessary.