The part that raises and lowers the height adjustment goes underneath of the hood on the vacuum cleaner, and is held on by the carpet height adjustment know on the top of the hood.
I've done a repair below that explains how to get the hood off of the roller brush housing, and replace the knob next to it which is the rug/floor selector knob which is the one right next to the height adjustment part. The repair on your machine will be the exact same process however. Hope this helped you:
If you've already changed the belts and the machine still won't run, it can really be only a few things.
The first thing you should check to make sure that the roller brush is good. You may do this by removing the bottom plate, and then taking the roller brush out of the vacuum
. Hold the bar using just your fingertips on the very ends of the brush on the bearing caps. With just holding the bearing caps with your fingers, use your thumbs to try and spin the bar. Does it spin freely without any resistance? If no, then you'll need to replace the roller brush. Here's a direct link to the exact roller brush for your Hoover Windtunnel Self-Propelled:Hoover Windtunnel Agitator Brush Part # 48414069
If the roller brush spins freely several times on each spin, then your machine may possibly have a bad Rug / Floor actuator arm. This part controls the internal pulley that stops the roller brush when you turn it from carpet to floor mode.
I'm guessing that this is probably a more likely cause of your brushes not spinning. Here's how you can check this part:
Step 1. Make sure that the vacuum is unplugged. Turn the machine upside down so that the brushes are facing upwards. I find the easiest way to do this is to put the brushes on top of a counter top or work bench with the handle of the vacuum resting on the floor. Remove the four screws that hold the bottom plate in place. Remove the bottom plate, both belts and then the roller brush from the machine:
Step 2. There are 3 screws that hold the top brush cover in place that need to be removed. On the right side the screw is down below the transmission to the right. There's also a screw in the agitator tray, in the middle that needs to be removed. NOTE: This small screw in the agitator tray is only present on some models, you's may or may not have this little screw, but all models will have all other screws circled. I have circled both screws that need to be removed:
The screws on the left side that need to be removed are also circled. One screw holds the upper brush cover on, and the other two screws secure the hose in place. Remove all three screws as well as the transparent hose cover:
Step 3. After all of these screws have been removed, there are two clips that are the last things holding the top brush cover onto the vacuum. Use a flat head screwdriver to push these clips off on both the left and right sides. The right side clip is near the pulley that the flat belt
rides on, and the left side clip is next to the internal hose.
Step 4. Once both of these clips have been pushed so the unhook from the lower agitator housing, remove the top cover. On the top you'll see two selector knows, one for the height adjustment, the other that controls the rug / floor setting. Turn the cover over and look at the opposite side of the knob that controls the rug / floor selector. There should be an arm that extends out that looks like this:
Sometimes this arm will break off, which will prevent the actuator arm from activating the rug carpet setting. The machine basically will always be set to bare surface floor mode. Is this arm broken off on yours? If yes, then here's how you can remove it from the machine.
Take your flathead screw driver, and place it underneath of the of selector knob on the top of the cover. Simply lightly pry upwards to separate the knob from the arm underneath:
Replace the actuator arm with a new one and see if this fixed your problem. If this was not the problem, there's really only one other possible thing it could be, but I rarely see this go bad. Please let me know if this fixed your problem, or if it is something else wrong. I'll be happy to then walk you through the last remaining possible problem.
I really hope that this repair was helpful to you. If you did find it to be helpful, help other Fixya users with the same problem find this repair by rating it helpful. You can do this by clicking on the thumbs up icons in the top of the repair.
Thank you very much,