Pool pump shaft seal leak...or something else?

Question

I have water leaking from behind the seal plate of my pool pump, under the motor. Exactly like a bad shaft seal. However...

I replaced the shaft seal. Still leaking.

I replaced it again, thinking I might have accidentally touched it or got some dirt on it. Still leaking.

I called a "pro", who also replaced the shaft seal. Still leaking. He then suggested rebuilding the MOTOR, which makes no sense to me. The problem is that water shouldn't be getting to the motor in the first place. How could rebuilding the motor be a possible solution?

At this point, the leak has increased from an occasional drop to more of a visible flow. I'm hesitant to run the pump at all now.

I replaced the seal plate, thinking maybe there was a small crack. Still leaking.

I replaced the impeller, again thinking maybe there is a crack. Still leaking.

As far as I can tell, that pretty much exhausts the list of relevant parts that could be replaced. I also replaced the impeller screw and gasket, but I don't think that would be related to the leak.

I'm pretty sure (say 99%) the water is not coming from somewhere else and running down under the motor, but at this point I'm not going to reject anything out of hand. I can post a picture of the leak if that would be helpful.

What else can I do? Is it possible the repair guy was onto something with rebuilding the motor?

This is a Pentair Whisperflo pump.

Answer 1

I replaced the motor, and that seems to have fixed the leak.

I suspect that during my first attempt to replace the shaft seal, I damaged something in the motor while struggling to remove the impeller. After that, the shaft was probably slightly off center, such that the two sides of the seal were not properly aligned.

It's possible that just replacing the bearings might have fixed the problem too, but I didn't feel confident that I could do that successfully. And the typical cost to pay someone else for that is about the same as a new motor anyway.