S15/T15 Jimmy 2WD L4-119 1.9L VIN A 2-BBL (1983)
Brake Rotor/Disc: Technical Service Bulletins
Disc Brake - Surface Refinish (Semimetalic Brake Lining)
Number:
83-I-106
Section:
V
Date:
August, 1983
Subject:
DISC BRAKE SURFACE REFINISH - ALL EQUIPPED WITH SEMIMETALLIC BRAKE LININGS
TO:
ALL CHEVROLET DEALERS
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 because
they are less tolerant to a rough refinish surface which can temporarily reduce brake effectiveness.
The original equipment new disc brake rotors have an initial rubbing surface finish of 10 to 50 microinches 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 brakes lining requires a
microinch 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 have the 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 microinch.
To become familiar with the required surface finish, drag a penny over the surface of a new rotor from parts stock or one on a new vehicle. If your brake
equipment cannot produce an equivalent finish when correctly used, contact the equipment manufacturer for corrective instructions.
