CAT 308E2 ( TMX00137 ) Customers complaint the boom would be hard or slow to lower at times, I could duplicate the problem, Main pump 4496 psi, pilot 600 psi, Removed the boom spool, nothing found, pulled the boom vented check valve found the plastic washer behind the spring was sideways in the bore,replaced the vent check valve, replaced the boom relief valve, switched the pilot lines with the swing, same problem ( to rule out the joystick ) after reassembly the boom will raise, but not lower... any insight would be appreciated
just an idea to rule out some tings, ave you tried lowering it wit te engine off, sould be able to for a few seconds after turning off as long as te pilot accumulator still as pressure. You can try removing te vented ceck valve completely and see ow it reacts. And yes my keyboard just broke so i'm missing te letter "h" ..........
I forgot to add that, First thing I found was no nitrogen charge, so I replaced and charged it, With engine off the stick, bucket will slowing lower, but not the boom, it actually jumps up when i pull back on the stick instead of lowering when the stick is pushed down
I removed the Vent Check valve and now the boom works correctly ! What's the deal and what does that valve do ?? FYI it's a new valve.
Maybe you ave a piece of te plastic stuck in te orifice ole in te boom spool so it's not venting it to tank allowing te ceck to open. Pull te spool and examine it closely. By te way, I'm in te market for some letters h