another wiper problem

ok, sorry, it is a 3 speed motor, and it does have a ground connected to one of the bolts that hold it to the firewall but the holes in the housing have rubber insulators. I'm not sure how it could be getting a ground from there. The armature looks good ie no burnt spots and it wont "catch" if you move the wiper arms by hand.
I wonder if I made the problem worse when I took the butt end off of the motor (2 long aluminum screws) and painted it. I painted the end of it where it touches the reduction gear housing, does the main motor housing have to be grounded to the rest of it?
oh, and it also works if I "push" in on the motor. I'll be playing with it tonight ( the wiper motor that is) and I'll post what I did wrong :) . The problem is that it will work for a few minutes while I'm testing it, but when I need it, it's dead. :(