Maybe someone here can help me, Im stumped on this. I fired up the trencher and the hydraulic pump for the backhoe isnt pumping any fluid. I pulled off the hose from the tank to the pump and fluid dumped out. But running the engine with the hose off the pressure side has no fluid comming out. I pulled the pump apart and everything inside looks fine. Is there something in a hydraulic pump that would cause this? Its on a case 40+4 super trencher.
If what your saying is true, fluid available to pump from supply line but nothing coming out open pressure line when engine running, it sounds like you have a problem with what drives the pump. Like it's not turning when the engine is running. Just a guess.
Check the splined coupling close. A lot of times the shaft goes into the coupler past the shaft. The splines will strip out in the coupler but leave a small length of good splines on the end were you can see easy at first glance and think they are good but after the first 1/8 inch or so the coupler will be worn round.
Some bozo had the front of the pump on backasswards, I unbolted the front of the pump and flipped it around so the intake side was on the other end and it works. I got the trencher at auction in pieces. I have alot of welding to do on the little dozer blade now.
dont u just love auctions
Nothing like a liquid overhaul to make them look new.
there was only one other guy bidding once it passed $225, if it wasnt for him I could have got a pretty good deal.