Hey there seems to be another newer saying too.
Sorry Schrade I didn't mean to jinx ya.
One thing I noted from your pics was excessive grease that could contaminate the commutator so a suggestion would be to go easy on the dielectric grease on re-assembly. I actually don't use any on the brush assemblies or near rear bearing and have not had any problems. I would consider the money spent on a rebuild toward higher education.
Scott, your idea seems to me to have merit as I have seen bearing spin if they are not locked in tight by fit. I like it.