hi i have a 92 is grey market ex200-1. the boom wont raise. it will kinda raise with the arm tucked and drops if you try and feather it. down has no power and wont even raise the tracks. all other functions work fine. it has been converted before i acquired it to all manual pilot controls and no electronics. the main pumps have 4000 psi in all other functions and 1500psi boom up and very low boom down. pilot pressure is 400psi to valve body when using controls so that seems to be fine. i swapped out relief valves and that didnt work. any ideas would be great. thanks
Simplest answer is one or both boom cylinder pistons have bad seals. Only takes one to lose force in both directions. You can try removing both rod end hoses and cap the hoses, gently try lifting the boom. If you get oil shooting out of either cylinder without the boom lifting it's bypassing the piston seals.
Cap and plug the lines at the cylinders and see if your pressure comes back.
Thanks for the help. One cylinder leaks bad. Time to learn cylinder rebuilding.
Yee Haw.... :Banghead
you may have already figured out by now but the piston nut torques to somewhere near 8-15k. you need a cylinder shop to take the nut off the rod.