Many Roomba vacs use an identical gear configuration within the “side brush motor” component. Three plastic gears mesh to transfer motor torque to the a spinning brush. Typically the middle gear fails when one or more gear teeth shear–this causes the brush to spin intermittently or not at all.
I cannot source this specific gear. I’ve played the Google Keyword Search game for much too long in a futile attempt to locate a vendor of these sort of gears. Ideally, I’d like to replace the plastic gears with brass or steel. But at this point, I’ll settle for an exact match part.
The images below illustrate my frustration. The newer looking gear is a supposed identical/compatible replacement (from an eBay reseller). It didn’t work. From the images, it’s pretty obvious this gear is not an exact match.
Any advice in the form of working links and/or websites is appreciated.