[Al Skierkiewicz]

As Ken has said earlier, a small tywrap works pretty well if all that is broken is the retaining tang. Make sure that the brush assy slides into place correctly and does not move around, then apply the tywrap around both brush assemblies directly behind the brushes. Don't forget that the fan end of the motor is the brush end. Don't cover the exhaust ports with the tywrap or the motor will overheat.
If the end assy is broken and the brushes do not align properly, there is virtually nothing you can do to fix this. Epoxy might make it ok to use on a proto robot or as an emergency spare. I wouldn't trust it for competition. I saw too many teams die in matches when their brush repair failed or the brushes fell out.