Regal V6-252 4.1L VIN 4 4-BBL (1983)
Brake Pad: Technical Service Bulletins
Disc Brake - Rotor Surface Refinish
Model Year 1983
Bulletin No. 83-159
File in Group 50
Number
1
Date
July '83
SUBJECT:
DISC BRAKE SURFACE REFINISH
MODELS AFFECTED: ALL EQUIPPED WITH SEMIMETALLIC BRAKE LININGS
Semimetallic brake linings have been selected for many new vehicles based upon brake system performance requirements. In order to maintain this
performance, semimetallic linings are also specified for service replacement.
Good contact is important between the rubbing surfaces of any brake system. But this is more important with semimetallic lining 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 to 50 micro inches and all have a nondirectional swirl pattern.
SERVICE RECOMMENDATIONS:
^
Routine replacement of disc brake shoe and linings does not require rotor refinish.
^
Should rotor refinish be required because of parallelism, runout, or because of deep scoring, the semimetallic brake lining requires a micro inch
surface refinish like 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 rotors from service stock, "do not" refinish the surface as these parts are to recommended finish. It also is not required to refinish a
rotor on a vehicle which has a smooth finish.
When refinishing brake rotors for semimetallic 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 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 10 to 50 micro inches.
To become familiar with the required surface finish, drag a fingernail or a penny 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.
