i just changed the belt on the attachment (the thing with the roller for cleaning the carpet) for my canister vacuum. not too difficult, however i did have to call up the sears center for some advice.
if you have a rubber bumper surrounding the attachment, then this needs to come off first. where the arrows are for the screwdriver pry up is where you need to start. the rubber bumper will slide up, and come off. you only need to remove the bumper until you get to the front part. it does not need to completely come off.
then the 2 screws on the bottom need to come out.
at this point the top is ready to come off. there are 2 tabs next to the part where the hose goes into the attachment (one on either side) as well as the 2 tabs where you use the screwdriver to pry the tabs off. after releasing the tabs, start to pull the top off, and lower the hose part so it is horizontal to the ground (otherwise it will prevent you from getting the top off).
now, there is a white (or grey depending on how dirty it is) protective plastic piece that has 2 tabs that can be unlatched by hand. unlatch and pull in a rotating fashion towards the front of the attachment. it should come off with no problems.
at this point, you should be able to see the roller and belt. PAY ATTENTION AS TO WHAT IT LOOKS LIKE so it's easier to put it back together. pull the roller straight up, and the belt should fall right off (meaning the belt has a lot of slack in it).
clean the inner houseing and roller as necessary. you are in there you may as well. the instructions on the white/grey housing piece talk about a washer on either side of the roller on the inside of the metal piecies that hold the roller in place. i wasn't able to see them, so hopefully they are still there.
after cleaning, replace the belt around the motor part first, then around the roller. use a little muscle, and put the roller back into place making sure the metal pieces on the outside of the roller line up and fit in correctly.
replace the white/grey housing piece by inserting the 5 tabs on the front into the little holes, then rotating back down onto the motor/roller. it should snap into place. you should hear the tab on each side snap, otherwise it might not be in all the way.
replace the outer housing paying attention to make sure the tabs line up (the 2 on either side of the hose and the 2 where the arrows are on the bottom).
replace the screws.
now slide the rubber bumper on either side back down onto the attachment and you are done! congrats
steve, April 2007