Operation CHARM: Car repair manuals for everyone.

Refinishing Rotors


Do not refinish brake rotors when performing routine brake maintenance such as replacing worn disc brake pads. Refinish a rotor only under the following circumstances:
1. There is a complaint of brake pulsation.

2. There is scoring greater than 1.5 mm (0.060 inch). All brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension and not a refinish dimension. Do not use a brake rotor that, after refinishing, will not meet the specifications shown on the rotor; always replace it with a new rotor.

Accurate control of the rotor tolerance is necessary for proper performance of the disc brakes. Machining of the rotor should be done only with precision equipment. Machining equipment should be serviced on a regular basis following the manufacturer's recommended maintenance procedure.

When refinishing rotors, refer to the equipment manufacturers instructions or guidelines. The attaching adapters, tool holders, vibration dampeners and tool bits must be in good condition. Always use sharp cutting tools or bits and use only replacement cutting bits recommended by the equipment manufacturer.

Dull or worn tools have a poor surface finish which will affect braking performance. Vibration dampening attachments should always be used when refinishing braking surfaces. These attachments eliminate tool chatter and will result in better surface finish. Make sure these adapters are clean and free of nicks.