Fleetwood V8-368 6.0L VIN 9 FI (1982)
Brake Pad: Technical Service Bulletins
Brakes - Rotor Refinishing/Pad Replacement
Bulletin No.
T-91-41
File in Group
5
Number
38
Corp. Ref. No.
075003R
Date
Feb. 1991
SUBJECT:
DISC BRAKE ROTOR REFINISHING/PAD REPLACEMENT
MODELS AFFECTED:
ALL MODEL YEAR CADILLACS
Some change may be perceived in braking effectiveness after rotors have been refinished and/or disc brake pads have been replaced. Lining materials
have been formulated for increased lining life and to reduce brake squeal. Federal regulations currently prohibit the use of asbestos in Original
Equipment Manufactured (OEM) front disc brake linings and will totally ban asbestos from all OEM brake linings in the near future. Due to these
changes, initial rotor surface finish is more critical than in the past and is required for good brake performance.
Following are recommended procedures to assure proper performance of the brake systems on all vehicles after rotor and/or pad service has been
performed:
1.
When performing routine brake maintenance such as replacing disc brake pads or shoes, DO NOT refinish disc brake rotors or drums unless:
A.
There is a brake pulsation condition present and this pulsation is found to be caused by the brake rotors or drums.
B.
The rotors and/or drums are excessively scored. Surface scoring that does not exceed 1.2 mm (.050") on rotors or drums should not affect
brake operation.
Before removing rotors from the hub assembly, mark the rotor and wheel stud so that the rotor may be reinstalled in the same position.
If rotors are removed, it is very important that rust and scale be removed from the rotor and hub mating surfaces. Failure to do so may introduce
excessive lateral run out when the rotor is mounted on the brake lathe or when the rotor is reinstalled to the hub.
2.
When refinishing disc brake rotors, it is important that the brake lathe be in good operating condition and that all tools or bits are sharp.
Recommended vibration dampeners and/or adaptors should be used and should be clean and free of nicks. The following table shows the
recommended procedure for rotor machining:
Rough Cut
Finish Cut
Spindle Speed
150 rpm
150 rpm
Depth of Cut (per side)
.127 mm (.005")
.051 mm
(.002")
Tool Cross Feed Per Rev
.152 mm - .254 mm
.051 mm (.002") max
(.006 " - .010")
Vibration Damper
yes
yes
Sand Rotors - Final Finish
no
yes
It is important that a rough and a finish cut be made. All brake lathes use a single-point cutting tool which is not capable of giving the necessary
surface finish. A SECONDARY FINISHING OPERATION MUST BE PERFORMED TO OBTAIN THE NECESSARY SURFACE FINISH.
An acceptable finish can be obtained using the Ammco Model 8350 Safe Swirl Disc Rotor Grinder, or equivalent, using 120 grit sandpaper and
sanding each rotor surface with moderate pressure for a minimum of 60 seconds with the rotor turning at 150 rpm. An alternate method is to use a
sanding block with 150 grit sandpaper. With the rotor turning at approximately 150 rpm, sand each side for a minimum of 60 seconds using
moderate pressure.
After the rotor has been sanded, the surfaces must be cleaned with a solvent such as brake cleaning fluid, denatured alcohol, or equivalent.
THE FINISHED ROTOR SURFACE SHOULD BE AS CLOSE TO THAT OF A NEW ROTOR AS POSSIBLE. FAILURE TO OBTAIN THE
