SLUSH BUILD-UP ON PARKING BRAKE CABLE

VEHICLES AFFECTED: 1988-89 C/K TRUCKS

Some 1988 and 1989 C/K trucks may experience a condition of slush build-up on the parking brake cable. The build-up is the result of the front tire splashing unusual amounts of ice and slush onto the parking brake cable. If the build-up is severe enough, the added weight on the parking brake cable can cause slight brake drag. To address this condition, a procedure has been developed that consists of an added cable support bracket under the vehicle between the #1 body mount and the cable connector or the #2 body mount.

Service Procedure:

Park Brake Cable Support Bracket Installation (refer to figures 1 and 2).

1. Block front wheels.

2. Release parking brake.

3. Locate parking brake cable bracket (4) midway between the #1 and #2 body mounts for extended cab vehicles as shown in Figure 1. Locate the bracket between the #1 body mount and the cable connector (6) for regular cab models as shown in Figure 2. Do not locate the bracket closer then three (3) inches from the cable connector.

4. Mark and drill a 7/16 inch diameter hole using bracket (4) as a template.

CAUTION:

Check inside of frame to ensure that fuel filter, fuel line, electrical harness, and brake lines are clear of drilling area.

5. Mark and drill a 17/32 diameter hole for the anti-rotation tab 29/32 inches to the rear of the 7/16 diameter hole.

6. Loosen equalizer nut (1) to relieve cable tension and remove connector (6) from parking brake cable.

7. Install bracket (4) with screw (2) and nut (5). Torque nut to 15 - 20 Nm (135-180 in. lbs.).

8. Install grommet (3) over cable and thread cable through hole in bracket. Snap grommet into bracket. Lubricate with GM P/N 993037 lubricant or equivalent.

9. Reinstall connector (6) and finger tighten equalizer nut (1) to take slack out of cable.

10. Adjust parking brake as described below.

Parking Brake Adjustment

The parking brakes must be adjusted whenever the parking brake cables have been replaced or disconnected. Before adjusting the parking brakes, check the condition of the service brakes. The service brakes must be adjusted properly before proceeding with the parking brake adjustment.

Inspect the parking brake system for free operation. The brake lever must return to the released position without sticking or binding. If a problem exists, check the cable routings for kinks or binding. Clean and lubricate the parking brake assembly and cables with brake fluid.

1. Block the front wheels.

2. Raise and support the rear axle with suitable safety stands.

3. Loosen the equalizer nut (1).

4. Set the parking brake cable to four clicks.

5. Adjust the equalizer nut (1) until the wheels will not rotate forward without a moderate drag.

6. Release the parking brake and rotate the rear wheels. There should be no brake drag.

7. Remove the safety stands and lower the vehicle.

8. Unblock the front wheels.

Parts Information

Part Number Description Quantity ----------- ----------- -------- 15639028 Bracket, Park Brake Cable Support 1 15530620 Grommet, Bracket 1 11504595 Screw, Bracket 1 11509415 Nut, Bracket 1 993037 Lubricant as required

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.