Chart 1

Good contact is important between the friction surfaces of the brake system. With semi-metallic linings, it is important to have good refinished rotor surfaces. A poor finish on one rotor can result in reduced brake effectiveness. This may result in a brake lead condition if installed opposite a properly finished rotor.

The original equipment new disc brake rotors have an initial surface finish of 20 to 60 micro inches and all have a non-directional swirl pattern.

SERVICE RECOMMENDATION

^ Rotor refinish requires a micro-inch surface refinish equivalent to the new vehicle rotor specification.

^ The recommended procedure for obtaining this finish is as follows:

Rough Cut Finish Cut

Spindle Speed 200 RPM 200 RPM
Depth of cut per side .005" .002" Tool
Cross Feed Per Rev. .006 - .010" .002" Max.
Vibration Dampener Yes Yes Swirl
Pattern - 120 GRIT No Optional*

* Duplication of new rotor and smoother finish for best initial brake effectiveness.

When installing new rotor from service stock "do not" refinish the surface as these parts are to recommended finish.

When refinishing brake rotors the following is important:

^ The brake lathe must be in good working order and have capability to produce the intended surface finish.

^ Use correct tool feed and arbor speeds. Too fast a speed or too deep a cut can result in a rough finish.

^ Cutting tools must be sharp.

^ Adapters must be clean and free of nicks.

^ Lathe finish cuts should be further improved and made non-directional by dressing rotor surface with a sanding disc power tool (AMMCO Model 8350 Safe Swirl Disc Rotor Grinder or equivalent).
^ Rotor surfaces are to be refinished to 20 to 60 micro-inch.

To become familiar with the required surface finish, drag a fingernail over the surface of a new rotor from parts stock or one on a new vehicle. If your brake equipment cannot produce this smooth a finish when correctly used, contact the equipment manufacturer for corrective instructions.