Refinishing

REQUIREMENTS
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:
^ There is a complaint of brake pulsation.
^ There are heat spots or excessive scoring.

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 will not meet the specifications. If the rotor thickness will be less than specifications after refinishing, the rotor must be replaced. A rotor which has been refinished too thin will not have proper heat transfer capabilities.

Accurate control of the rotor tolerances - 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 - 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 leave a poor surface finish which will affect initial 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.

PROCEDURE
Locate the deepest score and turn the rotor micrometer knobs until the tool bit bottoms out at the deepest point of the score. Zero the scale and back out the tool bits. Advance the cutter hand-wheel until the bits have cleared the inner edge of the rotor face. Adjust the micrometer knobs for approximately 0.0127 mm (0.0005 inch) more than the first reading. This will ensure clearing the rotor in one cut.

The Optimum Speed For Refinishing - braking surfaces is a spindle speed of 200 rpm. Crossfeed for rough cutting should range from 0.15 to 0.25 mm (0.006 to 0.010 inch) per revolution. Finish cuts should be made at Crossfeed no greater than 0.05 mm (0.002 inch) per revolution.

It Is Very Important - that the rotor surface be made non-directional by dressing the rotor surfaces with a sanding disc power tool such as Ammco 8350 Safe Swirl Disc Rotor Grinder, or equivalent, using 120 grit aluminum oxide sandpaper. Sand each rotor surface with moderate pressure for a minimum of 60 seconds. An alternate method is to use a sanding block with 150 grit aluminum oxide sandpaper. With the rotor turning at approximately 150 rpm, sand each rotor surface for a minimum of 60 seconds using moderate pressure. After the rotor has been sanded, clean each surface with denatured alcohol or suitable brake cleaner.


After Refinishing Rotors - replace any rotor that will not meet minimum thickness specification.

Rotor Thickness (Minimum):
^ 2-Door: 8.0 mm (0.315 inch)
^ 4-Door: 15.0 mm (0.590 inch)