BRAKE FEEL (NEW BRAKE ASSEMBLY AND NEW VACUUM BOOSTER P/N)

BRAKE FEEL (NEW BRAKE ASSEMBLY P/N AND NEW VACUUM BOOSTER P/N)

VEHICLES AFFECTED: 1985-88 M VANS WITH POWER BRAKES ------------------

A new brake pedal assembly and booster has been released to change the feel of the brakes on M Vans equipped with power brakes. This new assembly and booster increases the pedal height and gives the impression of a firmer pedal by altering driver ergonomics. All vehicles built with power brakes after the following breakpoints are manufactured with this new pedal assembly and recalibrated brake booster.

Model Year Plant VIN ---------- ----- --- 1988 Baltimore GMC: JB520855 Chev: JB181948

Service Procedure:

Follow the removal and installation procedures for Brake Pedal Replacement in the 1988 Light Duty Truck M-Van Service Manual (G.M.C. X-8830 or Chevrolet ST-372-88

1. Remove the brake pedal assembly as per the instructions in the Service Manual.

2. Remove the vacuum booster assembly as per the instructions in the service Manual.

3. The master cylinder can be unbolted and moved out of the way without disconnecting the brake lines or totally removing the master cylinder.

4. Inspect the following parts for wear and replace as necessary:

a. bushing - pivot shaft (Figure 1, Item 2) b. retainer - pivot shaft (Figure 1, Item 1) c. retainer - booster push rod (Figure 1, Item 9) d. gasket - booster mounting (Figure 2, Item 2)

5. Discard the following parts: a. old brake pedal (Figure 1, Item 4) b. old vacuum booster (Figure 2, Item 3) c. old actuator (not pictured)

Note: A separate stop lamp actuator bracket is not supplied for this service procedure as this bracket is now an integral part brake pedal assembly.

6. Install new brake vacuum booster per Service Manual instructions.

7. Bolt master cylinder to new brake vacuum booster.

8. Install new brake pedal assembly per Service Manual instructions.

9. Adjust the stop lamp switch per Service Manual instructions.

Note: Always ensure that the brake system is operational after performing brake work before returning the vehicle to the customer.

Parts Information

Part Number Description Quantity ----------- ----------- -------- 15617145 Pedal and lever package 1 18012882 Booster Ass'y.-Power brake 1 15598962 Bushing-Pivot shaft 2 15598965 Retainer-Pivot Shaft 1 10040797 Retainer-Booster push rod 1 9791640 Gasket-Booster Mounting 1

Note: The new booster assembly can be identified by the assembly code "LM" on the part.

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.