Pentair Centrifugal Pump Shaft Seal U109-433SS

The Pentair U109-433SS shaft seal is ideal for repairing leaks between the pump housing and motor, especially when servicing or rebuilding a pump. Over time, seals wear out due to heat, friction, and chemical exposure, leading to slow drips or steady leaks. Replacing the seal restores the pump’s watertight integrity and helps extend the life of the motor.

This seal is widely used in residential pool pumps, spa pumps, and some commercial applications, making it a go-to part for technicians and DIY repairs alike.

Best for
Fixing leaking pool or spa pumps
Preventative maintenance during motor replacement
Pentair / Sta-Rite pump rebuilds

Not ideal for
Pumps requiring specialty Viton or salt-heavy-duty seals
Non-compatible pump models (always verify part match)

Not all shaft seals are created equal. The U109-433SS features a stainless steel spring, which offers better corrosion resistance compared to standard steel springs—especially important in chlorinated environments. While some aftermarket seals may look similar, they often lack the same material quality or precision fit, which can lead to premature failure.

Pro Tip:
Never touch the ceramic or carbon faces with bare fingers during installation. Oils from your skin can create hot spots and reduce seal life. Use a clean cloth or gloves when handling these surfaces.

Common signs of a failing shaft seal include water leaking between the pump housing and motor, rust forming on the motor face, or unusual noise caused by bearing damage. If you see any of these symptoms, replacing the shaft seal promptly can prevent more expensive repairs and keep your pump operating smoothly.