The polishing brush roll was difficult to install for several reasons, most of them deriving from the fact that I am not a Hoover expert.
First, there were no instructions with the set. I imagine there were instructions at some point but they must have gotten lost somewhere along the way.
[A guick diversion -- I remember in one of the old Hoover upright vacuum cleaner manuals a page or two of written description and photos of the floor polisher attachment, however, in going through all the manuals I currently have at hand, I don't seem to have that manual any longer. If someone out there has it, could you please scan it for me? I'd like to add it to the web page I just put up.]
Then back to the topic. Okay, lacking instructions, it took several tooth-gnashing attempts to get the thing into the motor housing before I realize I was trying to put it in upside-down! It has a curved chrome casing that wraps around the brush, and when trying to put it in, I did not realize that the chrome casing would curve around and down into the motor housing when you push the roller down in.
Second, the roller only fits in one way (same as with the regular agitator roll), and the only way to tell the correct method is that one of the little 'tips' on the ends of the brush roller that slide down into the motor housing is just a teeny, leeetle bit fatter than the other one. (Why, one has to wonder, couldn't they have made these tips different-enough in size to make it READILY apparent to the naked eye?!)
Third, it was difficult to get the belt down into the channel leading to the motor shaft. Because the chrome housing of the polisher head is in the way. You have to kinda hold the polisher in one hand very close to the motor housing, while pushing the belt down inside with the index finger of your other hand. Then once the thing is in place, you have to reach your fingers way inside the channel to pull the belt up and over the motor shaft.
Honestly! I'd say the average homemaker would have given this procedure one, maybe two attempts, and then given up. Just as well, really, since it really does not do a good job. It just doesn't have the torque, weight or power.