Grand Prix V8-350 5.7L DSL (1983)
Brake Rotor/Disc: Technical Service Bulletins
Disc Brake - Surface Refinishing Guidelines
Number
83-I-114
Section 5 Date 07/83
Subject:
DISC BRAKE SURFACE REFINISHING GUIDELINES - ALL MODELS EQUIPPED WITH SEMI-METALLIC BRAKE LININGS
Semi-metallic brake linings have been selected for many new vehicles based upon brake system performance requirements. In order to maintain this
performance, semi-metallic linings are also specified for service replacement.
Good contact is important between the rubbing surfaces of any brake system. This is more important with semi-metallic linings as they are less tolerant to
a rough refinished surface which can temporarily reduce braking effectiveness.
The original equipment new disc brake rotors have an initial rubbing surface finish of 10-50 microinches and all have a nondirectional swirl pattern.
SERVICE RECOMMENDATIONS:
^
Routine replacement of disc brake shoe and linings does not require rotor refinishing.
^
Should rotor refinishing be required because of parallelism, runout or deep scoring, the semimetallic brakes lining requires a microinch surface
refinish like a 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 rotors from service stock, DO NOT refinish the surface as these parts are already to a recommended finish. It also is not required to
refinish a rotor on a vehicle which has a smooth finish.
When refinishing brake rotors for semi-metallic linings, 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 nondirectional by dressing motor surface with a sanding disc power tool (AMMCO Model
8350 Safe Swirl Disc Rotor Grinder or equivalent).
^
Rotor surfaces are to be refinished to 10-50 microinches.
To become familiar with the required surface finish, drag your 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 of finish when correctly used, contact the equipment manufacturer for corrective instructions.
