Pentair Challenger Front Housing O-Ring

The Pentair 355329Z is the front housing o-ring for Challenger pool pumps, both the high flow and high head models. It is the genuine Pentair part and is also listed as 355329.

Square, not round

This ring has a square cross section. The groove in the Challenger front housing is cut for that profile, so a round ring of similar diameter will not seat or seal the same way. Order the correct part rather than substituting from a generic assortment.

When to replace it

The housing o-ring seals the front housing to the seal plate. As it ages it flattens and hardens, the seam starts to drip, and the pump can pull air on the suction side. It is a standard item in a Challenger rebuild alongside the lid o-ring and shaft seal. A light coat of silicone o-ring lubricant on installation helps it seat and lengthens its life.