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:

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 the specifications after refinishing, replace the rotor.

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.

Use only precision equipment in order to machine the rotor.

Service the machining equipment on a regular basis. Follow the manufacturer's recommended maintenance procedure.

When refinishing rotors, ensure that the following components are in good condition:

Always use sharp cutting tools or bits. Use only replacement cutting bits recommended by the equipment manufacturer.

Dull or worn tools leave a poor surface finish that will affect initial braking performance.

Always use vibration dampening attachments when refinishing braking surfaces.

The attachments eliminate tool chatter and will result in a better surface finish.

Ensure that the adapters are clean, and free of nicks.

1. Locate the deepest score.
2. Turn the rotor micrometer knobs until the tool bit bottoms out at the deepest point of the score.
3. Zero the scale.
4. Back out the tool bits.
5. Advance the cutter handwheel until the bits clear the inner edge of the rotor face.
6. Adjust the micrometer knobs for approximately 0.0127 mm (0.0005 in) more than the first reading. Adjusting micrometer knobs will ensure clearing the rotor in one cut.
7. The optimum speed for refinishing braking surfaces is a spindle speed of 200 rpm.
8. Ensure that the crossfeed for rough cutting ranges from 0.15 to 0.25 mm (0.006 to 0.010 in) per revolution. Make the finish cuts at a crossfeed that does not exceed 0.05 mm (0.002 in) per revolution.

Important: Ensure that the rotor surface is made nondirectional. Dress the rotor surfaces using a sanding disc power tool such as Ammco 8350 Safe Swirl Disc Rotor Grinder, or equivalent, using 120 grit aluminum oxide sandpaper.

9. Sand each rotor surface using moderate pressure for a minimum of 60 seconds. Use a sanding block with 150 grit aluminum oxide sandpaper as an alternate method.
10. With the rotor turning at approximately 150 rpm, sand each rotor surface for a minimum of 60 seconds using moderate pressure.
11. After the rotor has been sanded, clean each surface using denatured alcohol or a suitable brake cleaner.
12. After refinishing the rotors, replace any rotor that will not meet a minimum thickness of 20 mm (0.787 in).