We see damage like this all of the time, most likely caused by a dasher blade pin!

Litre Service offers keyway cutting, spline cutting, and full dasher refurbishment. We also carry an inventory of refurbished dashers with brand new drive shafts.

Works for all Hoyer FP pump models, simply adjust your pump housing so that the ports are facing the direction shown in the photo below and look for the position of the indent. This dictates your product flow.