Can the main control valve of the komatsu PC300-5 be used on the PC400-5
I believe they are the same valve blocks. You might be able to check the part number for each and go from there. I know for certain that they work the same. Are looking at replacing the entire valve or only one half?
The entire valve
I believe they are the same. My service manual shows both PC300 and PC400-5 and there is only one set of graphics for the main control valve. I suppose you could check the physical size if you had one of each somewhere close by. Also check the tube sizes the connect to the valve. If they are the same size it will work.