Seville V8-273 4.5L (1989)
3.
a. On Cimarrons, hold park brake release in return position while lightly applying the parking brake to stop the vehicle.
b.
On all other models, hold the gear selector in Neutral while applying the parking brake lightly to stop the vehicle. Moving the gear selector
to any drive position allows vacuum release of the parking brake. (Failure to release the parking brake could result in rear brake lock.)
4.
OBSERVE: Does the parking brake pedal pulsate? Is there noticeable vibration in the vehicle (different than road induced)?
5.
If either of these conditions is present, refinish or replace drums/rotors as required.
If no brake pulsation is indicated, test the front brakes.
Front Brake Pulsation Test (Full Brake System):
1.
Perform 20 to zero mph brake test:
a.
Accelerate vehicle to 20 mph.
b.
Place selector in neutral.
c.
Apply brakes lightly to stop the vehicle. If pulsation is felt, service front brakes as described in this bulletin. If no pulsation is present,
continue to step 2.
2.
Perform 45 to 50 mph brake test:
a.
Accelerate vehicle to 50 mph.
b.
Place selector in neutral.
c.
Apply brakes using medium pedal pressure. If pulsation is felt, service front brakes as described in this bulletin. If no pulsation is present,
continue to step 3.
3.
Heat up the brake system by performing 10 stops from approximately 30 mph using medium pedal pressure. Then repeat 20 to zero mph test in
step 1.
a.
If pulsation is felt, service front brakes as described in this bulletin.
b.
If no pulsation is present, check tires and drivetrain components for other possible causes of customer complaint.
Rotor Refinishing
ROTOR REFINISHING
Rotor refinishing should only be performed when rotor thickness variation (non-parallelism) is present or when the rotor surface has scoring grooves
deeper than .015 inches. Replacement rotors taken from stock should be mounted and checked for lateral run out; and if run out exists, then the rotor
must be refinished on the vehicle.
When rotors are refinished, a correct surface finish is important for satisfactory braking. Following a light finish-cutting operation of between .001 and
.002 inches, correct surface should be obtained by rubbing with 120 grit emery cloth. Surface finish may be checked by running a fingernail over the
surface of a new rotor from stock or one from a known good vehicle. For best results, cutting equipment should be maintained in correct working
condition. If an acceptable finish surface cannot be obtained, contact the equipment manufacturer for assistance.
On-Vehicle Rotor Finishing:
The recommended procedure for refinishing brake rotors is through the use of on-vehicle rotor turning equipment (Kent-Moore J-37704). This method is
particularly effective because it can compensate for stacked tolerances that cause rotor/bearing system run out, and help prevent a return of the condition.
Full set up and operating instructions are provided with the equipment. Contact Kent-Moore for ordering information.
We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse,
indicate any preference for, or assume any responsibility for product or equipment from these firms or for any such items which may be available from
other sources.
