I admit I'm wrong and this is one of those cases. Received this kit and had to re-drill the side brush hole to a larger diameter to get the screw right and read the internal threads on the side brush motor. Second, I installed the rubber and bristle brushes and the Roomba started rattling horribly. I originally rated this kit 1 star due to all the issues I was having. Put the original brushes back and everything works as before. I read about Roomba rattles online and found that the brush gear is clogged with hair, dust, dirt etc and causing the rattle. Just google "Roomba clunking" and you will find tutorials. I took mine apart, and while the box itself was almost perfectly clean, I saw that the grease had come off most of the gears. I added some white lithium grease (from a local auto parts store) to each gear, put in the new brushes from the kit and everything worked as expected. I'm only upgrading this kit from 1 star to 3 stars because I still need to drill out the remaining side brushes to make them usable. If you don't mind doing a bit of work on this set, the price is good.