To change a broken vacuum belt, unscrew all of the screws holding together the vacuum head, remove the cover, remove all of the threads wrapped around the vacuum brush, and disconnect the belt from the motor shaft and brush drum. Thread the new belt around the brush drum, and connect it to the motor shaft's roller. Always make sure to unplug the vacuum cleaner before opening the head or removing and replacing the vacuum belt.
Some vacuum cleaner models do not have screwed-down heads. When changing the belt on these models, simply pop open the vacuum head on the designated opening, and replace the belt in the same way.
When replacing the vacuum belt, make sure you have all of the proper tools and necessary materials. This process usually requires a Phillips head screwdriver for removing the head as well as a straight slot screwdriver for prying the old vacuum belt off the drum and slipping the new belt back onto it. The straight slot screwdriver can also help reconnect the vacuum belt to the motor shaft. To double-check that the belt was properly replaced, use a hand to spin the brush drum to test the drum's tension and mobility.