A vacuum belt is a critical part in most upright vacuums. The belt rotates the brusher bars which are used to beat and agitate dirt out of carpeting so that the vacuum can suck it out. The belt is one of the parts which needs to be routinely replaced to keep a vacuum running efficiently and effectively, and it is a good idea to keep a spare belt around if one owns a vacuum cleaner. Belts can be obtained from many hardware stores, and also directly through the manufacturer.
In the classic upright vacuum design, the bottom of the vacuum has a brusher bar which rolls over carpeting as the vacuum is pushed across the room. The stiff brushes and vibration of the vacuum pull the dirt out of the carpet, and the vacuum's suction pulls the dirt into the canister or bag. The belt is what pulls the brusher bar; when the vacuum is turned on, the motor moves a small bar which is connected to the brusher bar by the belt. Some uprights have a separate motor which powers the brusher bar, in which case they do not have belts.
Vacuum belts look like oversized rubber bands, which is basically what they are. As a result, over time, they stretch out. If a vacuum belt becomes too stretched out, it will start to lose contact with the moving parts of the vacuum, leading to a slowdown in movement. Old belts can also become frayed, eventually snapping. Typically, a vacuum belt needs to be replaced every four to six months, depending on how frequently the vacuum is used, and how well the belt was made.
It is important to use a belt which is the right size. Many belts have part numbers printed on them so that replacements can be ordered, and the part numbers are also printed in the vacuum manual. For consumers who do not have a manual, it is possible to note the make and model of the vacuum and take that information to a hardware store to get the part number. The new belt should look undersized, and it may require some effort to pull the belt over both of the connecting bars on the underside of the vacuum cleaner.
When a vacuum belt is replaced, after the belt has been looped over the moving parts, the brusher bar should be spun to make sure that the belt moves freely without snagging or stopping. Then, the base of the vacuum can be screwed or snapped back on, and the vacuum is ready for use. Making a note on the calendar is a good idea, so that it is easy to tell when the belt was last replaced.