CAMPAIGN: FRT. AIR BRAKE HOSE MAY RAPTURE/SERVICE PROCEDURE. GMC Truck GMC MD Conventional 97.5" 1988

Models: 1985-1990 C7D Medium Duty Trucks with High Cab Models (EPG) and 7,000# Air Brake Front Axles (FS2/FT2)

General Motors of Canada has determined that a defect which relates to motor vehicle safety exists on certain 1985-90 medium conventional high cab models (EPG) equipped with 7,000# air brake front axles (FS2/FT2). The front air brake hoses can contact the inner fender extensions. If this occurs, the inner fender extension can chafe the brake hoses and eventually wear the hoses to the point that a rupture would occur, resulting in a loss of front brakes. These vehicles are equipped with a dual braking system; part of the system will still work and allow the vehicle to be stopped, but over a greater distance. Loss of front braking at a time when minimum stopping distance is required could result in a vehicle crash, without prior warning.

To prevent this condition from occurring, it will be necessary to cut out a portion of the inner fender extensions on both sides of the vehicle. Additionally, both front brake hoses will be inspected for chafing and replaced if chafing has occurred.

VEHICLES INVOLVED:

Only the following VIN's are included in this recall:

1GDK7DlY2GV534030 1GDK7DlY5JV517083 1GBS7D4G6JV115102

All affected vehicles have been identified by the VIN listing provided to involved dealers with this bulletin. Any dealer not receiving a listing was not shipped any of the affected vehicles.

DEALER CAMPAIGN RESPONSIBILITY:

Dealers are to service all vehicles subject to this campaign at no charge to owners, 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 before reselling or releasing the vehicle.

Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer, and arrangements made to make the required modification according to instructions contained in this bulletin.

CAMPAIGN PROCEDURE:

Refer to Section 4 of the Service Policies and Procedures Manual for the detailed procedure on handling Product Campaigns. Dealers are requested to complete the campaign on all transfers as soon as possible.

OWNER NOTIFICATION:

All owners of record at the time of campaign release are shown on the attached computer listing and have been notified by first class mail from General Motors. The listings provided are for campaign activity only and should not be used for any other purpose.

PARTS INFORMATION:

Parts required to complete this campaign should be ordered through regular channels, as follows:

Part Number Description Quantity/Vehicle ---------- ---------------- ----------------- 2023204 Brake Hose (LH & RH) AR

PARTS AND LABOUR CLAIM INFORMATION:

Credit for the campaign work performed will be paid upon receipt of a properly completed campaign claim card, RAPID terminal or DCS transmission in accordance with the following:

Repair Code Description Time Allowance ----------- ------------------------- --------------- 2A Rework Inner Fender Shields .3 3A Replace LH Brake Hose .8 4A Replace RH Brake Hose .8 5A Replace Both Brake Hoses 1.6

Time allowance includes 0.1 hour for dealer administrative detail associated with this campaign. Parts credit will be based on dealer net plus 30% to cover parts handling.

SERVICE PROCEDURE:

The following service procedure consists of making a clearance cut-out in the inner fender extension and mud splash shield. Additionally, air brake hoses must be inspected for damage and replaced if necessary.

A. Inspection Procedure (See Figure 1)

1. Set parking brake.

2. Inspect air brake hoses on both sides of vehicle. If there is any sign of chafing or damage to the hoses at the inner fender area, remove and replace hoses as described in Paragraph "C".

B. Making Clearance Cut-Out In Inner Fender Extension and Mud Splash Shield

1. A template for the cut-out has been furnished. In addition, Figure 2 gives the dimensions for making a template, if necessary.

2. Using the template, mark the areas on the inner fender extension and mud splash shield on both the right and left sides of the vehicle. The location of the cut-out areas is shown in Figure 1.

3. The cut-out can be made using an electric saber saw with a metal cutting blade which will cleanly cut both the fiber glass inner fender extension and the rubber mud splash shield.

NOTE: Fiber glass dust can be very irritating to the skin and eyes. When cutting the fiber glass, wear long sleeved shirt and goggles.

C. Removal and Replacement of Front Air Brake Lines

1. Remove access panel section of engine noise shield to gain access to front air line and elbow fitting.

2. Remove clamps holding right and left front brake lines to inside of frame near elbow fittings.

3. Remove front brake lines from elbow fittings.

4. Remove elbow fittings from frame.

5. Remove plastic connecting hoses connecting front brake chambers to bracket elbows from the elbow at bracket.

6. Remove elbow fittings from brackets.

7. Remove front brake hoses and replace with new hoses.

8. Installation is reverse of removal.

NOTE: Apply sealer to all thread surfaces.

INSTALLATION OF CAMPAIGN IDENTIFICATION LABEL

Clean surface of radiator upper mounting panel and apply a Campaign Identification Label. Make sure the correct campaign number is inserted on the label. This will indicate that the campaign has been completed.

Dear General Motors Customer:

General Motors of Canada has determined that a defect which relates to inotor vehicle safety exists on certain 1985-90 medium conventional high cab models (EPG) equipped with 7,000# air brake front axles (FS2/FT2). The front air brake hoses can contact the inner fender extensions. If this occurs, the inner fender extension can chafe the brake hoses and eventually wear the hoses to the point that a rupture would occur, resulting in a loss of front brakes. These vehicles are equipped with a dual braking system; part of the system will still work and allow the vehicle to be stopped, but over a greater distance. Loss of front braking at a time when minimum stopping distance is required could result in a vehicle crash, without prior warning.

Instructions for performing this service have been sent to your GM dealer. Please contact your dealer to arrange a service date.

This letter identifies your vehicle. Presentation of this letter to your dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.

Further assistance, if required, may be obtained from our Customer Assistance Centre, toll free, by calling 1-800-263-3777.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.

***************************************************************************** *STG DISCLAIMER*

"THE TEMPLATE DISPLAYED IN THIS SERVICE PUBLICATION IS NOT INTENDED FOR USE" (Please refer to the actual publication for an accurate "TEMPLATE" to use in this service procedure.) *****************************************************************************

Object Number: 75320 Size: FS

Object Number: 80231 Size: FS

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.