To repair a leaking pool pump, first troubleshoot your pump to determine the origin of the problem by turning the pump on and observing where the leak occurs. If the leak occurs at a pipe connection and does not respond to tightening of the connection with pliers, the connection may require a new gasket or O-ring.
A pool pump with a leak that requires the installation of a new motor gasket or O-ring can be repaired only after the inlet and outlet valves of the corresponding pipes have been shut off. This step prevents water from back-flowing during the repair procedure.
Once the valves have been shut off, use an open-end wrench or ratcheting socket to remove the bolts at the motor mount and detach the motor from its housing. Pull off the motor gasket or O-ring, apply automotive grease on to the rim, align the replacement gasket to the freshly greased rim, and press it into place. Apply more automotive grease to the end of the motor shaft before putting the motor back and reattaching the motor to its basket housing.
Test the pump by turning it on and letting it run for a few minutes. If a minor leak is still present, you may be able to resolve oy by shutting off the pump and tightening the bolts again after having let water run through the pump.