Vacuum Brake Booster: Service and Repair

Vacuum Brake Booster Replacement (LY7)

Tools Required

J 22805-B Power Brake Booster Holder

Removal Procedure

Caution: When replacing the power booster brake, make sure that the cruise control cable is not routed between the booster and the cowl. If the cable is damaged or pinched, it must be replaced. Failure to do this could result in personal injury.

1. Disconnect the negative battery cable.
2. Remove the left instrument panel insulator.
3. Remove the brake apply sensor (BAS).
4. Remove the retaining clip and disconnect the brake booster pushrod from the brake pedal.
5. Remove the exhaust crossover pipe.
6. Disconnect the brake fluid level sensor electrical connector from the brake fluid level sensor.
7. Remove the brake pressure modulator valve (BPMV) bracket and fasteners.
8. Remove the master cylinder mounting nuts and separate the master cylinder from the vacuum brake booster and position aside.

Important: It is not necessary to disconnect the brake hydraulic pipes from the master cylinder or brake pressure modulator valve.

9. Disconnect the vacuum brake booster check valve from the brake booster. Position aside the vacuum hose and the check valve as an assembly.
10. Drain the cooling system.
11. Remove the coolant heater pipes from the engine.
12. Attach the J 22805-B to the booster using the master cylinder retaining nuts.




13. Unlock the booster from the front of the cowl.
Use a flat bladed tool to depress the brake booster locking tab (1) out of the cowl mounting flange, while turning the booster counterclockwise with a ratchet on the (2).
14. Remove the vacuum brake booster.
15. Remove the J 22805-B (2) from the booster.

Installation Procedure

1. Install the vacuum brake booster.
Position the vacuum brake booster on the cowl counterclockwise from the final installation position so that the locking flanges on the vacuum brake booster and on the cowl mounting flange engage.

Important: Ensure the locking tab and the flanges are in the fully engaged position.




2. Rotate the vacuum brake booster clockwise with a ratchet on the J 22805-B (2). DO NOT use a flat bladed tool in the locking tab to install the vacuum brake booster. When the vacuum brake booster is correctly installed, the locking tab (1) slides up the flange and engages the locking notch.
3. Remove the J 22805-B (2) from the installed vacuum brake booster.
4. Install the coolant heater pipes.
5. Position and connect the vacuum hose and check valve assembly to the booster.

Notice: Refer to Fastener Notice.

6. Position the master cylinder to the booster and install the master cylinder retaining nuts.

Tighten the master cylinder retaining nuts to 33 N.m (24 lb ft).

7. Install the BPMV bracket and fasteners.
8. Connect the brake fluid level sensor electrical connector to the brake fluid level sensor.
9. Install the exhaust crossover pipe.
10. Refill the cooling system.
11. Connect the brake booster pushrod to the brake pedal and install the retaining clip.
12. Install the BPMV to the bracket.
13. Install the left instrument panel insulator.
14. Connect the negative battery cable.