The belt wasn't tight enough at first. The brushes rotate when you tilt the vacuum cleaner backwards, but stop at the slightest resistance (e.g. even on the lowest carpet). We tried tape around the idler wheel first, but that wasn't enough to fix the issue. But we found a solution! We have found that the Lego hoop pictured here (part #61254) around the tension wheel provides the perfect extra tension and grip to allow the brushes in our Hoover Smart Car Wash + Automatic Cleaning Carpet (model FH52000) to rotate bring. We happen to have a lot of Lego pieces in our house, but you can order individual Lego pieces for pennies. An internet search for Lego 61254 should bring up websites to buy. I'll try to update this review as soon as I have time to try it out over time.
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