Cordless Vacuum Cleaner Head Repair Guide ​CRITICAL SAFETY WARNING: Before touching any internal components, remove the battery pack from the cordless vacuum or ensure it is completely powered off and unplugged from the charger. Accidental activation while handling the brush roller can cause severe finger injury. Work on a clean, stable surface. ​Required Tools ​Phillips head screwdriver (usually size #1 or #2) ​Flathead screwdriver or a small coin (for unlocking the quick-release brush cover) ​Utility knife or heavy-duty scissors (for cutting away debris) ​Small cleaning brush or old toothbrush ​Replacement drive belt (if your specific generic model uses a rubber belt mechanism) ​Step-by-Step Diagnostics ​When a vacuum motor runs but the brush bar fails to spin alongside a distinct burning rubber smell, the issue is almost always mechanical friction. The drive mechanism is trying to turn, but something is holding the roller completely still.