20 Most Recent Hoover U6437-900 / U6439-900 Windtunnel Bagged Upright Vacuum - Page 3 Questions & Answers

Need to replace both drive and roller brush belt. Can't just replace one even if the other is fairly new.

Its a bit tricky but with some patience you can replace it. I have linked a video that I think will be helpful.

heres a digram

unclog the hose to stop the blockage

This sounds like the switch is sticking closed and starting to fail. Replace the switch with a new one. http://www.ereplacementparts.com/hoover-u6439900-windtunnel-selfpropelled-vacuum-parts-c-37315_37337_37579.html

Remove belt and roller. Start motor- noise still there? If so noise is in the motor or caused by the motor.

for a temporary fix, double up a rubber band on the outer tip of the spindle. if the belt slips over that, it's stretched out too much. replace the belt

Belts will get loose in time and they must be replaced.

Did you use it to vacuum up fine materials like powder? If you cleaned the filters, but they are original to the machine, replace them. Try changing the bag to a fresh one as well. Beyond that, check how freely the brush turns. If it doesn't turn freely that can but excess load on the motor, if its covered in threads, remove those.

No suction usually caused by a clog or obstruction somewhere or the filters need to be replaced

There is a thermal reset inside the motor that shuts it off. There may be a clog.somewhere or something restricting the airflow, it could be clogged filters. If there are no clogs or restrictions it is possible the thermal reset is bad in which case you will have to replace the motor.

Make sure you have the right belt-the size should be stamped on the unit on in the manual. Turn the unit upside down and watch the operation-is it the motor or the rotor?