BRAKE LEAD/FRT BRAKE WEAR (REPLACE REAR BRAKE SHOES). GMC Truck GMC C Pickup

REVISION: 09/17/98 DIVS INVL 1 5 7

THIS BULLETIN IS BEING REVISED TO CHANGE A LABOR OPERATION NUMBER AND ADD INFORMATION TO THE MODELS AND CORRECTION SECTIONS. PLEASE DISCARD CORPORATE BULLETIN NUMBER 86-50-20 (SECTION 5 - BRAKES). ______________________________________________________________________

SUBJECT: BRAKE LEAD/PULL AND FRONT BRAKE WEAR (REPLACE REAR BRAKE SHOES)

MODELS: 1992-98 CHEVROLET AND GMC C/K MODELS WITH RPO JB8 1992-98 CHEVROLET AND GMC C/K SUBURBAN MODELS WITH RPO JD7 AND 6.5L OR 7.4L ENGINE 1996-98 CHEVROLET AND GMC G VANS WITH RPO JB8

CONDITION:

SOME OWNERS MAY COMMENT ABOUT THE VEHICLE LEADING OR PULLING TO EITHER SIDE WHILE APPLYING THE BRAKES, AND PREMATURE FRONT BRAKE WEAR, ESPECIALLY VEHICLES THAT HAVE BEEN USED TO TOW A HEAVY LOAD.

CAUSE:

CONDITIONS MAY BE CAUSED BY EXCESSIVE WEARING OF THE FRONT BRAKE MATERIAL. IMPROVEMENTS TO THE ABOVE CONDITIONS CAN BE GAINED THROUGH REAR BRAKE MATERIAL MODIFICATIONS. ON THE SUBURBAN MODELS, THE BEST PERFORMANCE FROM THIS NEW BRAKE MATERIAL CAN BE ACHIEVED WITH REPLACING THE PROPORTIONING VALVE.

CORRECTION:

REPLACE THE REAR BRAKE SHOES WITH DURA STOP(TM) BRAKE SHOE KIT. ON SUBURBAN MODELS, A PROPORTIONING VALVE MUST BE INSTALLED. **ALL OTHER MODELS (C/K,G), NO PROPORTIONING VALVE CHANGE IS REQUIRED.** USE THE PART NUMBERS LISTED BELOW. REFER TO SECTION 5C2 OF THE APPROPRIATE SERVICE MANUAL.

IMPORTANT: IF YOU ENCOUNTER DISC BRAKES THAT ARE EXCESSIVELY WORN ON THE INBOARD SIDE, WITH VERY LITTLE WEAR TO THE OUTBOARD SIDE, VERIFY THE CLEARANCE BETWEEN THE CALIPER AND THE STEERING KNUCKLE BRACKET STOPS. REFER TO SERVICE MANUAL SECTION 5-111 FOR ADDITIONAL INFORMATION ON THIS PROCEDURE. MEASURE THE CLEARANCES INDIVIDUALLY AND ADD THE CLEARANCES TOGETHER FOR TOTAL CLEARANCE BEFORE REMOVING THE CALIPER. IF THE CALIPER (TOTAL CLEARANCE) TO THE STEERING KNUCKLE STOPS IS UNDER 0.20 MM (0.008 IN.), YOU MUST CORRECT THIS BY FILING METAL OFF AT THE STEERING KNUCKLE STOPS IN ORDER TO OBTAIN A TOTAL CLEARANCE OF 0.25 TO 0.61 MM (0.010 TO 0.024 IN.). DO NOT FILE METAL OFF OF THE CALIPER.

PARTS INFORMATION:

P/N DESCRIPTION QTY --- ----------- ---

18029651 (17452R CANADA) SHOE KIT, DURA STOP BRAKE 1 (13 X 3.5 INCH - SUBURBAN) 15650150 (92-94 SUBURBANS) VALVE ASM., BRAKE COMB. 1 12548265 (95 & NEWER SUBURBANS) VALVE KIT, BRAKE COMB. 1

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

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

H0257 SHOES AND LININGS, DRUM BRAKE USE PUBLISHED LABOR - R&R OR REPLACE OPERATION TIME

H0780 VALVE, BRAKE COMBINATION USE PUBLISHED LABOR - REPLACE OPERATION TIME

IMPORTANT: LABOR OPERATION IS CODED TO BASE VEHICLE COVERAGE IN THE WARRANTY SYSTEM.

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.