Unplug the Kenmore Whispertone vacuum power cord from the wall outlet. Disconnect the power head wand from the power head. Raise the wand to the full upright position, press on the rear release pedal with your foot and pull the wand out of the power head.
Press in on both ends of the light cover on the top of the power head and pull the cover away from the vacuum. Push the bulb inward and turn it counterclockwise to remove it from the power head.
Remove the four cover screws on the top of the power head with a Phillips-head screwdriver. Turn the power head over so the beater brush is facing you. Insert a flat-head screwdriver into the side tabs where the cover connects to the bottom. Pry the tabs away from the bottom of the vacuum.
Turn the power head right-side up and press the wand release pedal. Lower the swivel where the wand inserts and raise the rear of the top cover forward. Slide the front of the top cover off the front edge tabs of the power head. Set the cover out of your way.
Insert the flat-head screwdriver between the end beater brush support and the inside of the power head. Gently pry the supports off the ends of the beater brush. The brush supports resemble two half-moons that cover the top of each end. Grab the beater brush with your fingers and pull it completely away from the belt and the power head. Slide the belt off the motor pulley.
Place the new belt around the motor pulley and slide the beater brush into the other end. The belt travels along a groove on the beater brush. Line the belt across the groove.
Insert the beater brush into the power head and push the supports over each end until they snap into place.
Line up the slots on the front edge of the cover with the tabs on the front of the power head. Slide the front of the cover into place and lower it over the power head. Press down until the locking tabs click in place.
Insert the retaining screws into the top of the cover and tighten with the Phillips-head screwdriver. Install the light bulb and press the light cover back into position.