Unplug the Hoover vacuum cleaner. Press the handle release lever and lower the handle to the floor. Turn the cleaner over so that the underside of the cleaning head is facing upward.
Remove the four screws at the corners of the cleaning head with a Phillips-head screwdriver. Pry the cleaning head plastic cover from the bottom of the Hoover vacuum with your fingers.
Check the flat belt for wear and/or rips. The flat belt is necessary for the self-propulsion feature. Replace the flat belt if it is found to be in disrepair.
Slide the flat belt from the drive shaft on the left side of the cleaning head. Slide the belt from the pulley in front of the drive shaft and discard the worn or damaged belt. Place the new flat belt onto the drive shaft and pulley.
Slide the brush roll belt from the drive shaft toward the rear of the left side of the cleaning head.
Pull the brush roll from the slots at either side of the Hoover's cleaning head. Slide the brush roll belt from the brush roll and discard it.
Slide the new brush roll belt onto the brush roll and position it in the groove formerly occupied by the worn belt. Replace the brush roll into the two slots on either side of the cleaning head.
Pull the belt over the drive shaft and rest it in place on the metal shaft.
Place the cleaning head cover back over the bottom of the vacuum and replace the screws at the corners of the cover with the screwdriver.
Plug the Hoover vacuum into the wall outlet and turn on the power switch on the Hoover's handle. Check the brush roll to make sure it is spinning to signify a proper belt replacement.