Everytime I replace my impellar, the rubber drive shaft seal that goes on top of the brass water pump collar is broken and shredded. It is cylinder shaped and has a tapered/mushroomed top. (not talking about the driveshasft seal under the impellar wear plate.) (The brass collar is worn too on the outside) Does this indicate another problem? The diagrams are unclear and the manual doesn't mention it. What is the correct installation of this rubber seal and what does it do.? It doesn't seam to seal anything too well and it looks to me like it doesn't do much. I know i am wrong about that but I hope I don't have a more serious problem.
