BRAKE NOISE (GRUNT/GROAN/GRIND CRUNCH/ COMING FROM BRAKES. Buick Riviera 1997

REVISION: 01/14/98

THIS BULLETIN IS BEING REVISED TO UPDATE THE MODEL YEARS AFFECTED AND TO INCLUDE REPLACEMENT OF THE BRAKE ROTORS. PLEASE DISCARD CORPORATE BULLETIN #73-50-23 (SECTION 5 - BRAKES). ______________________________________________________________________

SUBJECT: BRAKE NOISE (GRUNT/GROAN/GRIND/CRUNCH/SQUEAL) COMING FROM FRONT BRAKES (REPLACE FRONT BRAKE PADS/ROTORS)

MODELS: 1997-98 BUICK RIVIERA, PARK AVENUE 1997-98 CADILLAC CONCOURS, DEVILLE, ELDORADO, SEVILLE 1997-98 OLDSMOBILE AURORA 1998 MODELS AFFECTED WERE BUILT PRIOR TO NOVEMBER 1, 1997

CONDITION:

SOME OWNERS MAY COMMENT ON A GRUNT, GROAN, GRIND, CRUNCH OR SQUEAL NOISE COMING FROM THE FRONT BRAKES WHEN APPLYING THE BRAKES AT LOW SPEEDS (35 MPH - 0 MPH).

IMPORTANT:

THE PREVIOUS BULLETIN (#73-50-30) INSTRUCTED TO REPLACE THE FRONT BRAKE PADS. OWNERS OF VEHICLES THAT WERE SERVICED UNDER THE ORIGINAL BULLETIN GUIDELINES MAY NOW COMMENT ON A SQUEAL NOISE AFTER THE BRAKE PADS WERE REPLACED.

CORRECTION:

FOR 1997 VEHICLES THAT HAVE NOT BEEN PREVIOUSLY SERVICED FOR THE GRUNT, GROAN, GRIND OR CRUNCH CONDITION, REPLACE THE FRONT BRAKE PADS AND ROTORS WITH NEW BRAKE PADS, P/N 18024961, AND BRAKE ROTORS, P/N 18026591.

FOR VEHICLES THAT HAVE BEEN PREVIOUSLY SERVICED FOR THESE VARIOUS NOISE CONDITIONS AND NOW EXHIBIT A SQUEAL CONDITION, REPLACE THE BRAKE ROTORS ONLY WITH THE LARGER 8MM (.32 IN.) CHEEK ROTORS, P/N 18026591.

FOR 1998 VEHICLES BUILT PRIOR TO NOVEMBER 1, 1997, MEASURE THE ROTOR CHEEK TO VERIFY THE SIZE OF THE ROTORS ON THAT VEHICLE. VEHICLES PRODUCED AFTER APPROXIMATELY NOVEMBER 1, 1997, WILL BE BUILT WITH THE LARGER 8 MM (.32 IN.) CHEEK ROTORS AND THE UPDATED BRAKE PADS AND SHOULD NOT EXHIBIT THE ABOVE CONDITIONS. TO ACHIEVE THE PROPER ROTOR MEASUREMENT, MEASURE ONLY ONE SIDE OF THE ROTOR FROM THE COOLING FIN AREA TO THE OUTER BRAKING SURFACE (MEASURE ONLY 1 ROTOR CHEEK). THE OLD DESIGN ROTORS HAVE 6 MM (.24 IN.) CHEEKS. THE NEW DESIGN ROTORS HAVE 8 MM (.32 IN.) CHEEKS.

PARTS INFORMATION:

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION LABOR OPERATION NUMBER DESCRIPTION TIME --------------- ----------- ---------------

H0042 PAD AND ROTOR USE PUBLISHED LABOR REPLACEMENT OPERATION TIME

H0127 ROTOR REPLACEMENT USE PUBLISHED LABOR ONLY OPERATION TIME

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.