I have repaired my main circulation pump and polaris pump 3 times over the years. They are both circa 1985 units and virtually identical. The carbon-steel water seal leaks and damages the bearings by diluting the grease. The pumps can be disassembled and both the forward (near pump) bearing and rear bearing replaced. Remove motor end cap to restrain the pump shaft and allow impellor to be unthreaded from the pump shaft.

The tricky part is getting the three, long, skinny (3/16" I think) through-body bolts to come loose w/o twisting off. I now have only two bolts in my main pump motor, but that is adequate. If they twist off, you may be able to remove them once the assembly is apart by long soak heating the aluminum body w/ propane torch and turning the stub (hopefully enough) w/ vise grips to remove the bolt.

On reassembly I use generous anti-sieze on the long bolts to allow easy future removal. It worked on my last main pump repair, and 2 long bolts are still intact.

I found bearing replacement at local autoparts dealer. I think front and rear bearings are identical. They may be available from pool parts outlet also.

good luck