A stack washer and dryer conserves floor space in the laundry room or a closet equipped with washer and dryer hookups. Because of the weight of a washing machine filled with water, which would make it unstable if elevated, the clothes dryer is always on top. Dryers spin wet clothes in a rotating drum powered by a drive belt connected to the motor. If the belt breaks or stretches to the point it can no longer turn the drum, you must replace it.
Pull the appliance away from the wall to shut off the two water supply valves for the washing machine and unplug the power cord.
Unscrew the water hoses from the back of the washer with pliers or a wrench to get them out of the way while you work on the dryer. Drain the hoses into a bucket to prevent spilling water.
Remove the screws attaching the back panel to the rear of the dryer. Take off the panel to expose the interior of the appliance. Locate the old drive belt around the drum or coiled loosely at the bottom of the machine if it has broken. The belt may also be hanging limply around the drum if it's stretched or broken.
Slide the replacement belt over the drum, grabbing the belt below the drum and squeezing to form a loop at the end.
Push the loop at the end of the belt through the tension pulley at the bottom of the dryer. The loop inserts between the pulley wheel and the bracket where the pulley is bolted into the bottom of the dryer.
Pull the end of the belt out the other side of the pulley and slip the end of the belt over the drive shaft on the motor. The pulley is on springs to create tension on the belt. Pull the pulley back toward the motor and drive shaft to create slack in the belt, making it easier to place over the drive shaft.
Slide the belt into the groove around the center of the dryer drum until the belt is seated in the groove. Pull one side of the belt to test the operation. The drum, pulley and drive shaft should all rotate.
Replace the back cover on the dryer and fasten with screws.
Reconnect the two hoses on the intake valves at the back of the washer. Tighten them with a wrench or pliers.
Plug in the power cord.