The Electrolux Harmony canister vacuum (EL6985) comes with a turbo nozzle attachment which works fairly well for cleaning small hairballs and other debris. The nozzle works by sucking air past a large paddle fast enough to spin it, causing the brush to spin as well. Over time, the gears and belt inside the nozzle can become clogged with hair and dirt, and the brush will stop spinning.
To take apart the turbo nozzle and clean it out, follow the steps below:
A. Turn the vacuum off and disconnect the turbo nozzle by pushing the button in and pulling the nozzle away from the tube.
B. There are four plastic wheels on the bottom of the turbo nozzle, two set far apart on the ends and two set close together by the tube. Remove the two wheels by the tube by popping them out with a flathead screwdriver (or your hand). When removing the wheels, there is a small shaft running through each wheel with nothing securing it - be sure not to lose those shafts. If either wheel does not spin freely on the shaft, clean any dirt from the shaft and wheel.
C. There are six Phillips head screws securing the bottom housing of the nozzle. Remove these screws and put them somewhere safe.
D. With the screws out, you can separate the top and bottom halves of the housing. If they don't separate easily, you can pry the top off with a small flathead screwdriver or a knife, but be careful because the plastic is soft and the edges will chip under pressure.
E. Once the top half is off, you have access to all of the interior components. (At this point, some people might want to take a picture of the nozzle's interior, to make it easier to put it back together later.) Remove the brush by popping the two black end caps out of the grooves they sit in and then sliding the brush free. Now you have access to the brush, the belt, the gear shaft and the paddle.
F. Clean all of the components and remove any built-up hair or other debris. Make sure no dirt is stuck in the teeth of the gears or stuck in the grooves of the belt. If hair is wrapped around the brush or a shaft, cut it off with a knife or scissors.
G. Once the inside of the nozzle is clean, put everything back together and make sure the brush, paddle, and belt all spin freely. Reassemble the nozzle by putting the two halves of the housing back together (be sure that the black plastic guard fits into the grooves in both the top and bottom halves), then putting the screws back in and reattaching the wheels.
H. Attach the turbo nozzle to the vacuum and turn the vacuum on to test it. The brush should spin when the vacuum is running; if it doesn't, the belt is likely not in place or there is still some dirt clogging the mechanism somewhere.