Service Procedure 1987 Models

1987 MODELS

Effective 1987 start of production, all Astro models were manufactured with new wheel cylinders described earlier in this bulletin; however, the new combination valve was not installed in the first several months of production. The new combination valve was installed effective with the following Vehicle Identification Number:

VIN HB137507

1987 vehicles produced prior to this VIN breakpoint can be modified by following the service procedure listed below:

SERVICE PROCEDURE

1987 Model 2.5L TBI and 4.3L TBI Engines

Note: Care must be taken to prevent brake fluid from contacting any painted surface.

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

FIGURE 1 - COMBINATION VALVE:

Replacement of the combination valve, Figure No. 1.

1. Disconnect negative battery cable.
2. Disconnect the four brake lines at the combination valve.
3. Disconnect electrical harness at the combination valve.
4. Disconnect combination valve at bracket on the brake booster and discard valve.
5. Install new combination valve (P/N 15571205)
6. Reverse above procedure for reinstallation and tighten bracket nuts to 50 N-m (37 ft.lbs.).
7. Reinstall brake lines and torque nuts to 25 N-m (18 ft. lbs.).
Parts List

1. Combination Valve (1) P/N 15571205
2. Wheel Cylinders (2) P/N 18004888
3. Brake Shoe Kit (1) P/N 12321427
4. Link Pin Kit (2) P/N 5464748
5. Brake Fluid DOT 3 P/N 1052535
(as required) or equivalent
6. Label (1985 4.3L Engine) (1) P/N 10066488
7. PROM for 1986 4.3L P/N 16068877 Federal engine
8. PROM for 1986 4.3L P/N 16068926 California engine

Parts are currently available from GMSPO.