Reply To: Series 80 water pump end play

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Dan, Sounds like you are on the correct path. Pierce used an “open” impeller, a style which does not develop as much thrust as most others. All impellers have thrust, trying to “climb” into the suction line, like a screw into a nut. However, the open side of these impellers allow some recirculation between the front face and housing, pushing back as a counter force to the suction thrust. The net result is very low levels of axial thrust. The washer you found is probably to hold the impeller in a fixed position, limiting the amount of recirculation to just balance these forces while maintaining pump efficiency.  See you at Gilmore; Herb