You don't repair them you replace them.lay the machine on it's back and you will see the motor brushes attached to the side of the motor housing.held with posi screws or 5.5mm headed screw.if carbon is less then 10mm they need replacing.as a test you can pull the carbon out of the holder and stretch them to see if the motor rotates.Do not use in this state as they can come out and totally destroy the motor
ck
May 2011