Need Help with Electirc Motor

[Zoomer]

I have a small motor on my autopilot that tends to stop. A slight tap on the housing starts it again, for a short while. I disassembled the motor and found what looked like black grease all over the inside. I cleaned the motor and brushes with acetone but I have the same problem. The brushes and springs seem fine. Should I use WD40 or something else?
Thanks,
Ed
s/v Dreamtime

[Christian Van H]

Hello. The commutator on the motor may be contaminated. Try rubbing it with a pen eraser to bring back a slight shine. Your bruses may be shot too. C

[perchance]

do not use wd 40. use electrical contact cleaner. Make sure the brushes slide freely in the holders and the commutator is smooth. Old brushes can cause arcing on the comm and cause severe pitting. A good polishing with 600 grit emery paper will usually take care of it. Brushes and springs should be replaced before they get to the point of ruining the comm. More power tools are destroyed because of this than for any other reason.