CAMPAIGN: POWER BRAKE VACUUM BOOSTER-FATIGUE CRACKS. Chevrolet Chevy Suburban

THE NATIONAL TRAFFIC AND MOTOR VEHICLE SAFETY ACT, AS AMENDED, PROVIDES THAT EACH VEHICLE WHICH IS SUBJECT TO A RECALL CAMPAIGN OF THIS TYPE MUST BE ADEQUATELY REPAIRED WITHIN A REASONABLE TIME AFTER THE OWNER HAS TENDERED IT FOR REPAIR. A FAILURE TO ADEQUATELY REPAIR WITHIN 60 DAYS AFTER TENDER OF A VEHICLE IS PRIMA FACIE EVIDENCE OF FAILURE TO REPAIR WITHIN A REASONABLE TIME. IF THE CONDITION IS NOT ADEQUATELY REPAIRED WITHIN A REASONABLE TIME, THE OWNER MAY BE ENTITLED TO AN IDENTICAL OR REASONABLY EQUIVALENT VEHICLE AT NO CHARGE, OR TO A REFUND OF THE PURCHASE PRICE LESS A REASONABLE ALLOWANCE FOR DEPRECIATION.

TO AVOID HAVING TO PROVIDE THESE BURDENSOME SOLUTIONS, EVERY EFFORT MUST BE MADE TO PROMPTLY SCHEDULE A SERVICE DATE WITH EACH OWNER AND TO REPAIR THEIR VEHICLE AS SOON AS POSSIBLE. AS YOU WILL SEE IN READING THE ATTACHED COPY OF THE LETTER WHICH IS BEING SENT TO OWNERS, THE OWNERS ARE BEING INSTRUCTED TO CONTACT THE NEAREST CHEVROLET ZONE OFFICE IF THEIR DEALER DOES NOT REMEDY THE CONDITION WITHIN FIVE DAYS OF THE AGREED SERVICE DATE. IF THE CONDITION IS NOT REMEDIED WITHIN A REASONABLE TIME, THE OWNERS ARE INSTRUCTED HOW TO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION.

DEFECT INVOLVED

GENERAL MOTORS HAS DETERMINED THAT A DEFECT WHICH RELATES TO MOTOR VEHICLE SAFETY EXISTS IN SOME 1979 AND 1980 C AND K 20,30 SERIES LIGHT DUTY TRUCKS EQUIPPED WITH VACUUM POWER DISC/DRUM BRAKES. VEHICLES PREDOMINANTLY AFFECTED ARE THOSE USED IN HEAVY DUTY OFF ROAD SERVICE. FATIGUE CRACKS MAY DEVELOP IN THE BRAKE VACUUM BOOSTER HOUSING CAUSING A VACUUM LEAK AND REDUCED BRAKE EFFECTIVENESS. AFTER PROLONGED USE, THE CRACKS MAY DEVELOP TO THE EXTENT THAT THE BOOSTER MAY SEPARATE FROM THE VEHICLE AND BRAKING ABILITY WOULD BE LOST. IF BRAKING ABILITY IS LOST, A VEHICLE CRASH COULD OCCUR WITHOUT PRIOR WARNING.

TO CORRECT THIS CONDITION, DEALERS ARE TO INSPECT ALL INVOLVED VEHICLES FOR FATIGUE CRACKS IN THE BRAKE VACUUM BOOSTER. IF NO CRACKS EXIST, A SUPPORT BRACE IS TO BE INSTALLED ON ALL VEHICLES. FOR THOSE INSTANCES WHEN CRACKS ARE DISCOVERED, A NEW BRAKE VACUUM BOOSTER AND SUPPORT BRACE ARE TO BE INSTALLED.

VEHICLES INVOLVED

INVOLVED ARE 1979-1980 C AND K 20-30 SERIES LIGHT DUTY TRUCK MODELS EQUIPPED WITH JB6 OR JB7 (VACUUM POWER DISC/DRUM BRAKES) AND ARE IDENTIFIED WITHIN THE FOLLOWING VEHICLE BREAKPOINTS:

PLANT MODEL YEAR FROM THROUGH

LAKEWOOD 1980 CCL24AA100253 CCL24AA136535 1979 CCL249A100353 CCL239A198489

BALTIMORE 1980 CCL24AB100004 CCD24AB165333 1979 CCL249B100001 CCD24AF394877

FLINT LINE 1 1980 CKL24AF300010 CCD24AF394877 LINE 2 CCW26AF100005 CKM26AF162183 LINE 1 1979 CCL249F300006 CCL249F506223 LINE 2 CCS269F100005 CKL269F214756

JANESVILLE 1980 CCM24AJ100002 CKM24AJ148490 1979 CCT349J100004 CKL249J186764

ST. LOUIS 1980 CCL24AS100003 CCM24AS188926 1979 CKL249S100019 CKL249S218550

FREMONT 1980 CKL24AZ100003 CCL24AZ143494 1979 CCL249Z100007 CCL249Z216447

OSHAWA 1980 CKL24A1100006 CCT23A1195117 1979 CKL2491100046 CCL2491209835

INVOLVED VEHICLES HAVE BEEN IDENTIFIED BY VEHICLE IDENTIFICATION NUMBER COMPUTER LISTINGS. COMPUTER LISTINGS CONTAIN THE COMPLETE VEHICLE IDENTIFICATION NUMBER, OWNER NAME AND ADDRESS DATA, AND ARE FURNISHED TO THE INVOLVED DEALERS WITH THE CAMPAIGN BULLETIN. OWNER NAME AND ADDRESS DATA FURNISHED WILL ENABLE DEALERS TO FOLLOW UP WITH OWNERS INVOLVED IN THIS CAMPAIGN.

THESE LISTINGS MAY CONTAIN OWNER NAMES AND ADDRESSES OBTAINED FROM STATE MOTOR VEHICLE REGISTRATION RECORDS. THE USE OF SUCH MOTOR VEHICLE REGISTRATION DATA FOR ANY OTHER PURPOSE IS A VIOLATION OF LAW IN SEVERAL STATES. ACCORDINGLY, YOU ARE URGED TO LIMIT THE USE OF THIS LISTING TO THE FOLLOW-UP NECESSARY TO COMPLETE THIS CAMPAIGN. ANY DEALER NOT RECEIVING A COMPUTER LISTING WITH THE CAMPAIGN BULLETIN WAS NOT SHIPPED ANY INVOLVED VEHICLES.

OWNER NOTIFICATION

OWNERS WILL BE NOTIFIED OF THIS CAMPAIGN ON THEIR VEHICLES BY CHEVROLET MOTOR DIVISION(SEE COPY OF OWNER LETTER INCLUDED WITH THIS BULLETIN)

DEALER CAMPAIGN RESPONSIBILITY

DEALERS ARE TO SERVICE ALL VEHICLES SUBJECT TO THIS CAMPAIGN, REGARDLESS OF MILEAGE, AGE OF VEHICLE, OR OWNERSHIP, FROM THIS TIME FORWARD.

WHENEVER A VEHICLE SUBJECT TO THIS CAMPAIGN IS TAKEN INTO YOUR NEW OR USED VEHICLE INVENTORY OR IT IS IN YOUR DEALERSHIP FOR SERVICE IN THE FUTURE, YOU SHOULD TAKE THE STEPS NECESSARY TO BE SURE THE CAMPAIGN CORRECTION HAS BEEN MADE.

INSPECTION PROCEDURE

CLEAN, AS REQUIRED, IN THE AREA WHERE THE REAR SHELL OF THE BRAKE VACUUM BOOSTER IS ATTACHED TO THE RIVETED MOUNTING BRACKET. USING A MIRROR, AS SHOWN IN THE ILLUSTRATION, INSPECT FOR CRACKS IN THE REAR SHELL OF THE BOOSTER. IF PRESENT, CRACKS WOULD STEM FROM BENEATH THE FOUR MOUNTING RIVETS ON THE LEFT AND RIGHT SIDES OF THE REAR SHELL OF THE BOOSTER, WITHIN APPROXIMATELY ONE-HALF INCH (1/2") AROUND THE CIRCUMFERENCE OF THE RIVETED BRACKET.

IF NO CRACKS ARE DETECTED DURING INSPECTION, USE SERVICE PROCEDURE "A" FOR BRACE ONLY INSTALLATION.

IF CRACKS ARE DETECTED DURING INSPECTION, USE SERVICE PROCEDURE "B" FOR BOOSTER REPLACEMENT (SEE NOTE IN "PARTS INFORMATION" SECTION OF THIS BULLETIN) AND BRACE INSTALLATION.

SERVICE PROCEDURE "A"

WITH THE FOLLOWING PROCEDURE, INSTALL BRACE-KIT P/N 14038672. SEE ILLUSTRATION FOR CLARIFICATION AND REQUIRED TORQUE VALUES.

1. REMOVE OUTBOARD NUT WHICH RETAINS MASTER CYLINDER TO VACUUM BOOSTER.

2. INSTALL "J" NUT P/N 561240* TO COWL REINFORCEMENT (SEE ILLUSTRATION.)

3. INSTALL BRACE P/N 14038661*. USE NUT REMOVED FROM MASTER CYLINDER AND BOLT P/N 11502673* TO RETAIN BRACE. TORQUE EACH TO THE REQUIRED TORQUE VALUES (SEE ILLUSTRATION).

* PART OF BRACE KIT P/N 14038672

SERVICE PROCEDURE "B"

FOLLOWING THIS PROCEDURE, REPLACE VACUUM BOOSTER AND INSTALL A BRACE KIT P/N 14038672.

1. REPLACE BOOSTER ASSEMBLY ON EITHER THE 1979 OR 1980 MODEL VEHICLES BY FOLLOWING THE BOOSTER REPLACEMENT PROCEDURE OUTLINED IN THE 1980 LIGHT DUTY TRUCK SERVICE MANUAL; SECTION 5 PAGE 5-39 UNDER THE TITLE: "POWER BRAKE UNIT VACUUM BOOSTER REPLACEMENT.:

USE P/N 18003678 FOR CK 20 AND 30 SERIES TRUCK WITH JB6 BRAKE SYSTEM.

USE P/N 18003686 FOR CK 20 AND 30 SERIES TRUCK WITH JB7 BRAKE SYSTEM.

A BRAKE SYSTEM USAGE CHART IS OUTLINED IN THE GMPD CATALOG, GROUP 4, PAGE 4-1B THROUGH 4-18B. (ALSO, SEE SERVICE PARTS IDENTIFICATION PLATE LOCATED ON INSIDE OF GLOVE BOX DOOR).

2. INSTALL BRACE KIT P/N 14038672 BY FOLLOWING SERVICE PROCEDURE "A".

PARTS INFORMATION

THE BRACE KIT, P/N 14038672, REQUIRED TO COMPLETE THIS CAMPAIGN ON ALL INVOLVED VEHICLES CAN BE ORDERED FROM GENERAL MOTORS PARTS DIVISION. TO INSURE ADEQUATE AVAILABILITY OF THIS PART INITIAL ORDERS SHOULD BE LIMITED TO IMMEDIATE NEEDS.

NOTE: AS THE NECESSITY TO REPLACE THE VACUUM BRAKE BOOSTER WILL BE MINIMAL, ORDERS PLACED TO GENERAL MOTORS PARTS DIVISION TO REPLACE THIS PART WILL REQUIRE ZONE APPROVAL BEFORE THE ORDER WILL BE FILLED.

PART NUMBER QUANTITY PER VEHICLE DESCRIPTION

14038672 1 BRACE KIT

18003678 1 VACUUM POWER BRAKE BOOSTER (WITH RPO JB6)

18003686 1 VACUUM POWER BRAKE BOOSTER (WITH RPO JB7)

CLAIM INFORMATION

SUBMIT A PRODUCT CAMPAIGN CLAIM WITH THE INFORMATION INDICATED BELOW:

PARTS FAILED **PARTS FAILURE LABOR LABOR *OTHER COUNT PART NO. ALLOWANCE CODE OPERATION HOURS HOURS

1 14038672 00 V0680 .2 .1

DESCRIPTION: INSPECT AND WHEN NO FATIGUE CRACKS EXIST IN THE BRAKE VACUUM BOOSTER INSTALL BRACE KIT ONLY.

2 14038672 00 V0681 .6 .1

DESCRIPTION: INSPECT FOR FATIGUE CRACKS ON THE BRAKE VACUUM BOOSTER AND IF THEY EXIST INSTALL THE APPROPRIATE BRAKE VACUUM BOOSTER AND BRACE KIT.

* CAMPAIGN ADMINISTRATIVE ALLOWANCE ** THE PARTS ALLOWANCE SHOULD BE THE SUM TOTAL OF THE CURRENT GMPD DEALER NET PLUS 30% OF ALL PARTS REQUIRED FOR THE REPAIR.

DEALERS WILL AUTOMATICALLY RECEIVE THE CORRECT PARTS AND LABOR ALLOWANCE BASED ON THE LABOR OPERATION PERFORMED.

REFER TO THE CHEVROLET PROCESSING MANUAL FOR DETAILS ON PRODUCT CAMPAIGN CLAIM SUBMISSION.

CAMPAIGN IDENTIFICATION LABEL

EACH VEHICLE MODIFIED IN ACCORDANCE WITH THE INSTRUCTIONS OUTLINED IN THIS PRODUCT CAMPAIGN BULLETIN WILL REQUIRE A "CAMPAIGN IDENTIFICATION LABEL." EACH LABEL PROVIDES A SPACE TO INCLUDE THE FIVE DIGIT DEALER CODE OF THE DEALER PERFORMING THE CAMPAIGN SERVICE. THIS INFORMATION MAY BE INSERTED WITH A TYPEWRITER OR BALLPOINT PEN.

EACH "CAMPAIGN IDENTIFICATION LABEL" IS TO BE LOCATED ON THE RADIATOR CORE SUPPORT IN AN AREA WHICH WILL BE VISIBLE WHEN THE VEHICLE IS BROUGHT IN FOR PERIODIC SERVICING BY THE OWNER.

APPLY "CAMPAIGN IDENTIFICATION LABEL" ONLY ON A CLEAN DRY SURFACE.

ADMINISTRATIVE PROCEDURE

REFER TO THE CURRENT CHEVROLET SERVICE POLICIES AND PROCEDURES MANUAL AND CLAIMS PROCESSING MANUAL FOR CAMPAIGN HANDLING AND ADMINISTRATIVE PROCEDURES.

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.