yeah i meant solder around the screw where is connects to the endbel.
I cant see where your caps hit the endbell, but I am sure thats just the pictures.
Have you tried cleaning the bearings and the motor? could be a build of of copper causing arking?
Does the armature move up/down when in the can, is there much play, it should move a little, but not be locked in there solidly.
Just throwing ideas out...