Put on a new hydraulic pump and couple. The splines were worn. There is no hydraulic function. Help. Really need it fixed. Loosened the nut for the outlet off the pump with it not running and oil started seeping as soon as it got loose. Didn't take it all the way off. Same with the diaphragm. Put 15 gallons of fluid in and the oil level is visible just taking off tua cap. When it is running, you can move any if the controls and there is no load. No idea what to do....
Did you remove and clean the suction screen during the pump swap? Any possibility you left a rag stuffed in the suction line? Don't ask me why I ask that, ahem...... Try loosening the four bolt connection on the suction side of the pump, see if you can burp any air out. Possible you got a pump that was assembled incorrectly, but that's a reach....
yeah, new pump should pump, verify direction of rotation?
Since there's oil in the pump run the machine a while working the levers and see if anything moves. Were the splines that the coupler goes on in good shape.
it holds 21.5 gallons but 15 should be enough. Just had mine off this spring to rebuild the engine. Drained the system and had no problems when I filled it back up as far as air goes. Can't remember if you could install it upside down or not, but I doubt it. I actually did the rag thing but remembered BEFORE I filled the system back up.
If none of the above suggestions help try, applying 15 PSI of air to the hydraulic tank. Could also be a internal problem (collapsed) with a suction hose if it has any .