Rotor Refinishing

CAUTION: When refacing a disc brake rotor the required 0.10 mm (0.004 inch) TIR (Total Indicator Reading) and 0.013 mm (0.0005 in.) thickness variation limits MUST BE MAINTAINED. Extreme care in the operation of rotor turning equipment is required.

Resurfacing Notes: This operation can be used when the disc surface is rusty or has lining deposits.
- A sanding disc attachment will remove surface contamination without removing much material.
- It will generally follow variations in thickness which are in the disc.

Refacing Braking Disc Notes:
- Rotors do not have to be refaced whenever a disc brake is relined.
- If the rotor surface is deeply scored or warped or there is a complaint of brake roughness the rotor should be refaced.
- The collets, shafts and adaptors on the lathe and the bearing cups in the rotor MUST be clean and free from any chips or contamination.
- When mounting the disc on the lathe, strict attention to the manufacturer's instructions is required.
- If the disc is not mounted properly the run-out will be worse after refacing than before refacing.

Fig 6 Refacing Brake Disc:

Fig 7 Refacing Brake Disc -- Final Finish:

- The use of a double straddle cutter which machines both sides of the disc at the same time is highly recommended.

Fig 8 Minimum Disc Thickness Marking:

Measurements and specifications when servicing the braking disc:

NOTE: All braking discs (rotors) have markings for minimum allowable thickness cast on an un-machined surface.
- This marking includes 0.76 mm (0.030 inch) allowable disc wear beyond the recommended 0.76 mm (0.030 inch) of disc refacing.
- This surface may be as shown, or on an alternate surface.

Do Not Reface Beyond 21.16 mm (0.833 in)
- Allows for Wear of 0.76mm (0.030 in.)

Minimum Allowable Thickness 20.4Omm (0.803 in)

NOTE: For additional information on how to use a micrometer, see Fundamentals and Basics. Fundamentals and Basics