To replace the drive belt as on my Kenmore model 116 (others may be different), remove the cover (slide two latchs outward) and the light/agitator cover (release the small loops attached to the rubber 'bumper' edges, then pinch two clips at back of cover and lift up from the back, rotating it forward). Pull the rubber 'bumper' edges away from the ends of the roller, lift the roller straight up, and the pieces that hold the roller at either end will slide up in their slots. It is difficult to see this until the roller is lifted. Notice that the piece that is in each slot has the flat edge up, as they should be reinserted with this orientation. Fully remove the roller. Note that the belt placement order can be reversed (roller then drive axle), but there are some tight spaces and fairly sharp edges next to the path of the belt. With the agitator selector lever in the "Carpet" position (engaged/forward), place the good belt around the drive axle and also around the movable selector roller towards the rear of the housing. Stretch the belt to position it on the roller, then pull the roller forward to line up and insert the end pieces into the slots. This will likely be a hard stretch of the belt, and the entire housing unit will need held in place to make this stretch. Check that the belt is turning freely and is correctly lined up on the roller and the drive axle. This belt replacement can be achieved with two good hands and likely a foot or two to hold the housing, but additional hands should be very helpful. I sincerely pray for your patience and your fingers when making this belt change.
MrL4JC in K-town, December 2009