I have added an auxiliary power beyond block to my 1971 Ford 4000 tractor. It had a double spool block to provide two sets of auxiliary hydraulics to the rear of the tractor. I sandwiched the new block between the tractor and double spool block to provide hydraulics to the FEL I installed on the tractor. I replaced the hydraulic hoses that were worn and changed the hydraulic fluid. NOW NOTHING WORKS! My hydraulic pump is internal and not mounted on the left rear of the tractor. How do I purge the air out of the pump? I disconnected the PB line from the FEL and put it into the tank fill and ran the tractor for 45 min. NOTHING! NO FLOW! How do I purge my pump?