I've got two pumps and two filters. One of them blew its bearings a year and a half ago. I did that one, and when the other one goes, I'll do that one too.
Bearings are less than $10 each from Grainger. You should be able to cross reference with the number stamped on the rubber seal. I used a cheap 3 jaw puller from harbor freight. To put the new ones on, I used a 4" nipple of black pipe that was just larger than the shaft but the same size as the inner race. I carefully hammered it back on using a hammer. The correct way would be to use a press if you can get access, but my cheap man's way has worked just fine so far. I'm hooking up the plumbing later this week to open up my pool, so I can let you know if I'm good to go with year number two.
Bearings have a finite life, so I fully expect pump number two to need to be done very soon, and I won't hesitate to redo it. I just can't see replacing the whole motor if it's just the bearings. If there's nothing wrong with the case or the windings, it seems like a waste of money.
I bumbled my way through the job (had never done one before) and it probably took about 2-3 hours. I fully expect the second go around to be less than an hour.
Here's some pictures to see what the motor looks like removed from the housing. The gooped up grease should be on the inside of the bearing, not the outside, and is the clear evidence that the bearing was shot. The bearing in the bottom picture had the exact same problem, it's just on back side.
