I have a Twist & Vac that I forgot and now I know why. The other day I took it apart and found the belt was stretched and the brush wasn't spinning. Couldn't find the instruction manual but found it online. I thought the riddle had something to do with the location of the belt. And yes, I found that I put the new belt in incorrectly. You need to rotate the whisk attachment so that it runs straight when you put your belt on. "not twisted on the engine pulley". bar up. When you rotate the nozzle, it's in a position you wouldn't normally use a vacuum in, "they call it the upright position". The front cover where you can see the motor pulley to tighten the belt was confusing at first how to remove it but it is flexible and will come loose. Easy to take off and put back on once you get used to it. 2. It is very important that when you put the strap on the stirrer (brush whisker) and put it back into the attachment, you need to line up the strap with the small tab on the other side of the attachment. It is located opposite where the screws will be screwed later, it is located "in the middle” inside the nozzle. On my Twist & Vac, the strap on the agitator ends "centered" on a small bump and aligns with this tab. . That way it will be straight with the right tension and >>> it will be protected under the center 'bar' of the cover once it's screwed down. If this is done incorrectly, the tape will move. I think I used to have a belt on either side of the raised area which caused it to move and heat up. I just got the carpeted stairs deep cleaned and didn't have to press the vacuum as hard to clean the cat fur as I've done with others. Another thing I noticed is that not only does the hair get stuck around the beater brush, it also gets stuck around the shaft above it (motor pulley). Check these areas for debris when cleaning large amounts of hair. I think it can stop around the pulley if the belt isn't rotating properly, heats up and the belt stretches. You'll understand what I mean when you watch it. I looked at the manuals for both vacuums and they seem to be identical on how to change the belt. This is a great vacuum cleaner. I haven't found anyone who can do carpet stairs like he does. I've had a few mess up your face when you use them on the stairs. this one is clean! Be patient while installing and cleaning around the belt and you will be glad to have this vacuum cleaner. I wish I knew this sooner :)