We have a Hitachi EX200-2. The hydraulics got horribly slow after changing out the main hydraulic pump. We put in a re-manufactured pump after the last one imploded. After pulling and cleaning the surge relief valve I managed to get most of hydraulics working at a reasonable speed. I put in a new main pressure relief valve and finally today got the pressures up to the specifications in the book. Unfortunately, I still have a problem with the boom and the arm (which was also occurring to a lesser degree prior to the pump imploding). When I try to cycle them together, only one will operate at once (the arm seems to dominate). I have checked the proportional solenoids and they are getting signal from the PCV and they Ohm out correctly. When I look at the troubleshooting chart one item that keeps coming up is the variable pressure compensated valves. I wonder if I have some debris in the variable pressure compensated valve?? Has anybody else had any experience with the variable pressure compensated valves (o rings or other issues)? They appear to be on the front of the main control valve. I am wondering if anybody has had any luck getting them out and reinstalling them without removing the main control valve. Thanks, Ray
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