The ridged part is actually part of the pump. You must replace the pump in order to fix this problem. You can still use the machine without the roller brush working. I know it seems as if the roller brush is actually doing something but it is almost purely cosmetic. The wet shampoo carpet cleaning process is all about releasing the dirt from the carpet fibers and then sucking it up with the water. (A chemical process.) If you do replace the pump, the problem is likely to happen again unless you clean the roller brush, especially the ends, after every use.
www.bobsroswellvacuum.com, October 2008
