The problem is actually in the entire design of the brush motor pulley system. While you think that the belt is the culprit, or even the gear on the motor or brush roller side, those are symptoms of the TRUE problem, which is that there is too much tension put directly on to the shaft of an inadequately hearty motor. I will, of course, explain... Take apart the brush motor pulley assembly and you get down to the motor with a black shell screwed on to it by 2 smaller screws inside of the pulley housing. Take those off and you have the motor encased in a black rubber shell that holds on the thermal cutoff switch. Tug on the rubber and it will eventually loosen; it's just stuck at the screw holes where it's been screwed down tight against the motor for all of this time. That exposes the thermal cutoff, and you can undo the wiring harness from the motor at this point. Now you will be able to see the problem: push the shaft to the side in different directions and you'll notice that the shaft clicks over about...