Clean the Circuit First
Drain and flush the reservoir. Change the pressure and return filters. Clean or replace the suction strainer. Check the breather. The debris that killed the old pump is still in the system and it will find the new one.
Check the Suction Side
A restricted or leaking suction line causes cavitation, and cavitation destroys pumps quickly and repeatedly. Check the hose internally, not just externally, and check every joint on the suction side for air ingress.
Mount and Align
Fit the pump to the bracket and check coupling alignment and gap against the drive specification. A misaligned coupling puts side load on the shaft and kills the bearing and the seal.
Fill the Case
Fill the pump case with clean oil through the case drain port before starting. Running a piston pump dry for even a few seconds damages the shoes.
Prime and Bleed
Turn the shaft by hand where you can. Start the drive briefly at low pressure with the relief valve backed off, and bleed air from the highest point in the circuit.
Run In
Run at low pressure for ten to fifteen minutes, then raise the relief valve setting in steps to the working pressure, checking for leaks and listening for noise at each step.
Check After the First Shift
Check oil level, filter condition and case drain temperature after the first working shift, and again after the first week. Early filter contamination is normal after a repair and a filter change at that point protects the new pump.
