I've never heard of a motor bearing kit. Back in the day it was quite cheap to fit a new armature but the big pre-logic motor armatures became obsolete some years ago. I had a machine similar to yours in my store for some time, waiting for a replacement armature, then one day I was out walking and spotted a rusty wreck of a Hoover auto in a ditch. The only bit worth salvaging on the machine was the armature so I got my machine running and sold it!