One of my machines has a 2" x 10" cylinder controlled by a 4 way electric valve with a body type check valve in the manifold stack. At full retract, the mechanism attached to the cylinder must be accurately in place. The spool is centered in the valve and the check valve should prevent oil movement. The problem I have is the mechanism isn't locking up. If I grab it and pull, I can see the cylinder rod move about 1/4" or less. If I crank down the speed controls on the cylinder all the way, the cylinder locks up. I took the valve and check valve to our hydraulic guys' shop and they went over them and couldn't find a problem. When I remounted the valves, the machine worked ok for a couple of days. We did bleed out the lines and cylinder and found no air. But, that's what it feels like. I have a guy coming out Monday, I give up. What could it be? This machine is 40 years old, except for any moving part.
16 years ago