Not really applicable. OP did say something about 15 yrs old.

With newer motors, in case of bearing failure, you may be able to press
bearing(s) off/on- or any competent motor shop. That is how they're
assembled. Sometimes you can get some lube in with an oiler that's like
a hypodermic, through the lip-seal. Never say never.

No matter- Grainger or other supplier should be able to find
replacement for current stuff.

HTH,
J