1. A low height setting can cause friction between the brush and the flooring. This can put too much stress on the belt, causing it to break. You can adjust the height using the dial on the base of the vacuum.
2. Check the condition of the brush. Can the brush freely spin? Can the brush be removed and are the ends intact? If not, the brush is likely malfunctioning and causing the belts to break. You can order a new brush by clicking here: http://www.bissell.com/parts/?sc=part&productid=2455&partid=4877
3. Be sure that you only use genuine BISSELL® belts in your vacuum. Click here to order a BISSELL belt replacement pack:http://www.bissell.com/parts/?sc=part&productid=2455&partid=4680
Still need help? Please call us at 1-800-237-7691, Monday - Friday 8 a.m. to 10 p.m., Saturday 9 a.m. to 8 p.m., or Sunday 10 a.m. to 7 p.m. ET. A representative will be ready and waiting to help you out!