On my hover U6616-900 the self propell work fine on the med setting on med height carpet, but when I go to low height carpet and height set on med the self propell does not pull the vacuum and it is hard to push. Also if I raise the height to the highest setting the self propell works correctly and appears to clen. Any ideas? S/N 090400184555, think this vacuum is maybe 5 years old and my wife uses it lots. Should I think of maybe a complete overhaul or a replacement at this time?

It's an issue that the front roller isn't engaged. there's usually a belt connected to the roller on one side of it. That belt is connected to the same motor that develops the suction. You have to find that area and either pull the belt over the motor and/or the brush. Close it back up and turn it on again.

There is no answer for that. You must have vary thick padding on plush carpet. Usually the highest setting is high enough. Is it hard to push and pull?

Generally the belt is probably stretched and needs replacing but I have had several that required modifying the height adjustment assembly. Belt should be a bit of a fight to stretch and get the brush block back in properly to maintain resistance. The higher carpet causes the belt to slip and can even cause burn/wear from the motor shaft spinning in one spot. Sometimes people run them and burn through and break the belt. Generally you smell rubber burning if belt is slipping and burning. The height adjustment modification was a last resort and not easy! Not for the average person! Another post tells how to modify but better be handy!

Move the carpet height control switch to a higher position if the vacuum is difficult to push. If the setting is too low for the carpet being cleaned, the brushes press against the floor preventing the vacuum from moving easily.Set to a medium-high height setting then check.Slide the "Self-Propel" button to the "ON" position if the cleaner does not self-propel. -----------
The self-propel feature operates only when the cleaner switch and the self propel button are both ON. ---------- Try this settings and check.This should help.Thanks.Helpmech.

The self propelled unit might have broken, their is a metal wire that helps make unit work correctly

if not the height setting, then
there is an obstruction or the brush is getting worn out.

unfourtunatly it could be the height of your carpet also using on area rugs could cause it to do that too. check the brush roll and make sure it is spinning freely.

When you had the brush roll off, did the ends turn freely? If not then the brush won't turn and the belt will just slip. You would have to replace the brush roll if either of the ends are frozen. Other then that you would have to remove the top cover to see if there any broken parts, there is a spring loaded asm, it has a black wheel that will push the V belt when it is in the carpet setting and the handle is in the down position, it could be jammed so the roller is stuck.

· Sometimes grabs the carpet for no reason.
· Comes back too fast when I push it back.

I would advise you to ALWAYS to FIRST UNPLUG YOUR VACUUM before beginning any service procedure.
Self-Propelled WindTunnel by Hoover U6445906 Without knowing the brand name or model number you may have the height adjustment to low and the vacuum will say “bite down” on the carpet of which will make the belt burn and might leave marks on the carpet – and if you have a self-propelled vacuum it does come back fast if you because you have a transmission just like a car and you have to control the speed of the vacuum or because it may have a weak belt the vacuum will pull back easier – I really would like to know the brand name and model number so that I could accurately give a better answer . Recommended belt change for flat belt(s) are 4 to 6 months for better cleaning and one a year for a geared belt – both can stretch and lose their cleaning function

Very professional and useful account there of the problem and investigation so far! Unless you've got evidence that your machine is damaging the carpet, I'd be inclined to put a new belt on and see if that fixes it. Carpet makes the beater/brush roller much harder to turn than bare floor does, and this can be enough to start a loose belt slipping (after which things don't naturally improve themselves). A.