PowerBot R7040 Runs with disengaged powerbrush

Mine did the same thing, and progressively got worse…I found that the small belt in the power brush drive has missing sections and eventually never moved again. It’s pretty difficult to get to.

I’m also looking for a belt. Incredibly difficult to find!

Has anyone figured out where to get this belt? I would also like to find the two gears as well if possible. Ordering the entire assembly for $90 + shipping is one, expensive and two, a waste of a perfectly good motor.

I just ordered the 2M-136-6 (GT2-136mm) belt from Amazon for $7.99: https://www.amazon.com/gp/product/B07VZ5... This is to get me up and running.

Since I was thinking about it I ordered 3 spares from China, $0.40 each plus $4.00 shipping: https://www.robotdigg.com/product/805/13...

Be sure to specify the 136-2gt-6 belt (136mm long, 2mm tooth spacing, 6mm wide), or whatever size you need.

samsung should repair free of charge, this is a poor project

I found that when I spun my brush, there were sections where it was hard to turn. I think that if the motor tries to start in those positions it would get stuck and the vacuum would "pretend" to clean.

I took the motor and belt assembly out (requires removing the vacuum motor and screw on the bracket of the right section camera mount.) There's a single screw holding the motor and belt assembly and you can slide it out to the side of the robot. The belt was loose so it was cogging on the pinion every few revolutions. I opened the clear cover and reseated the screws that mount the motor. This gave tension back to the belt and the brush spins smoothly now.

Good luck to you if you try this fix! The robot has many wire harnesses, be careful not to pull or pinch them!

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 1-2mm depending on wear, in the direction of the belt's tension pulling on it. That's where the shaft has been pulled hard against the wall of the bearing and just eaten through it over time until the belt goes slack. Once the belt is slack enough, those teeth start skipping, making that grinding noise, and wearing down the teeth to compound the issue. Replacing the belt is an exercise in a complete PITA vacuum teardown to get to the brush motor assembly for a very short term fix since it's already too slack and will wear down the teeth on your new one quickly. You COULD switch to a 134mm belt, but there is unlikely to be enough of the bearing rubbed through to give you an additional 2mm of slack and not cause the vacuum to throw a C 01 code from feeling the additional tension and thinking something is caught in the brush. The only fix is to replace the entire motor, and the belt in the process since it's likely been worn down, but the motor bearing is just going to wear through again over time and you'll be right back here. There is likely nothing wrong with the gears in the rest of the housing, so if anyone is able to source the motor by itself, that is the least wasteful approach to fixing it

Bottom line is this is a faulty design by Samsung and they will never acknowledge it. We paid $500 for a vacuum that will regularly be taken down hard by a $1 motor.