A hydraulic plunger installation tool that exerts a hydraulic force on a plunger for a reciprocating pump to install the plunger into a pump cylinder opening. Maintenance of the pump typically includes repacking of the packing that surrounds the plunger and revalving of the pump's inlet and outlet valve. To allow repacking or revalving, the pump is disassembled and the plunger is removed. The hydraulic plunger installation tool is located at the pump cylinder on an upward facing nest with legs that provide a reaction point for a hydraulically actuated piston rod that is driven at one end by a hydraulic piston and engages the plunger at an opposite end during installation to push the plunger into the cylinder opening without the use of hammers by personnel.
