CAMPAIGN: REAR HYDRAULIC BRAKE TUBES MAY FAIL (SERVICE PROC.)

SUBJECT: REAR HYDRAULIC BRAKE TUBES MAY FAIL

MODELS: 1982 GMC C7D042 MEDIUM DUTY TRUCKS EQUIPPED WITH SINGLE BRAKE SYSTEM (JXP), H175 17,500 LB. REAR AXLE (H93), 10 STUD REAR DISC WHEEL (IRLF), AND 6.17 REAR AXLE RATIO (015).

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 leas a reasonable allowance for depreciation.

To avoid having to provide theme 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 in being sent to owners, the owner is being instructed to contact the nearest GMC Zone Office if their dealer does not remedy the condition within five days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they 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 1982 Medium Duty Conventional Model 7000 Series GMC Trucks equipped with a single hydraulic brake system and special equipment options; RPO H93 (H175 rear axle), RPO IRLF (10 stud rear disc wheel), and RPO 015 (6.17 rear axle ratio.) The brake tubes at the rear can develop fatigue crack at the base of the flare. This could result in a brake fluid leak and loss of braking capability. Loss of brakes could result in a vehicle crash without prior warning.

VEHICLES INVOLVED

The vehicles involved are certain 1982 Medium Duty Conventional C7D042 Trucks equipped with single hydraulic brake systems (JXP).

The specific vehicles involved in this campaign have been sold to Ryder Truck Rental.

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 used vehicle inventory or is in your dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling or releasing the vehicle.

OWNER NOTIFICATION

Ryder Truck Rental will be notified of this campaign on their vehicles by GMC Truck (see copy of owner letter included with this bulletin).

SERVICE PROCEDURE

1. Disconnect both ends of the brake lines and remove the hex nuts over the clip-on studs. Remove right and left rear brake lines.

2. Remove the junction block from the bracket attached to the differential housing.

3. Remove 2 bolts attaching the bracket to the differential housing and remove the bracket.

4. Install the new bracket (PN 15518961) on the differential housing and torque to 115-140 Nm (85-103 ft.lbs.).

5. Reinstall the junction block on the new bracket and torque to 27-34 Nm (20-25 ft.lbs).

6. Remove clips from the old brake lines and install in the same position on the new brake lines.

7. Position the new brake lines on the housing. Attach line fittings to the wheel cylinders. Do not tighten at this time. Position the line clip over the studs.

8. Install 3 clips on left hand line and 1 clip on right hand line in positions shown in illustration (Figure No. 1)

9. Locate position for 4 brackets (PN 15519369) to be welded on the axle housing as shown in illustration (Figure No. 1). Clean the weld areas and mark the bracket location on the housing.

10. Remove the brake lines.

11. Locate the brackets to their marked positions and weld the brackets to the axle housing. For manual arc welding, use E60xx or E70xx series welding rod. For MIG welding, use E-70S-3 electrode.

12. Reinstall and position brake lines and tighten tube nuts to 11-16 Nm (8-12 ft.lbs.).

13. Install clips to 4 welded bracket with attaching hardware. Attach original clips to studs with hex nuts. Torque all attaching nuts to 66-80 Nm (48-59 ft.lbs.).

14. Bleed brake lines as outlined in the Medium Duty Service Manual X8233.

15. Paint the 4 welded brackets.

16. Figure No. 2 shows a completed installation.

PARTS INFORMATION

The parts required to complete this modification are being shipped direct to Ryder Truck Rental.

Part Quantity Part Number --------- ----- ------ 1 Kit NPN Each kit will contain the following: 1 Bracket Asm. 15518961 1 Brake Pipe 2093810 1 Brake Pipe 2045781 4 Bracket 15519369 4 Clamp-Loop Cushioned 2001030 4 Bolt - 3/8" x 1" 9418822 4 Flat Washer 9421042 4 Nut 9437796

Parts an not to be ordered from or returned to the Warehouse Distribution Division General Motors (WDDGM).

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

Labor Operation *Time Trouble Number Description Allowance Code --------- ---------------------- ---------- ------ V2080 Install brackets and right 1.7 hr 96 and left rear brake pipes per instructions in service procedure.

* For dealer to receive Administrative Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.

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 (5) 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

Procedures covering this campaign are outlined in Section V of your dealership's "GMC Truck Claims Processing Manual" issued April, 1983.

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.