I have a Hoover Deep Cleaner with spinscrub.......I've never liked it very well because I didn't feel like it extracted as much water as it should. Not because of the suction (it has good suction) but it wasn't meeting the carpet with enough pressure....I think because my carpet is low pile berber..........I got this idea to add a hand weight to the top.......I simply taped it on........It makes the machine a wee bit harder to push but it's WORTH it because it's extracting a LOT more water by doing this...... Before doing this......It would extract up about 30 percent of a gallon of water......Now it's pulling up about 80 percent of what it puts down. Carpets are dry in four to six hours with the ceiling fans on.......It doesn't seem to be harming the machine at all....The spinscrub brushes are floating.....I made a vid if you want to see......

If your upright deep cleaner has floating brush heads......You might try it...Again.....I've done this several times and my machine is fine. Not sure how this would work on another upright deep cleaner.

I spilled some soda so I decided to video.......

Here is a link that might be useful: Hoover deep cleaner with a weight