Brake Booster Repair Procedures

Brake Booster Operational Test

1. 1
   Start the engine for one or two minutes, then stop it. If the pedal depresses fully the first time but gradually rises when depressed again, the booster is operating properly. If the pedal height remains unchanged, the booster is not operating.

   

2. 2
   With the engine stopped, depress the brake pedal several times. Then depress the brake pedal and start the engine. If the pedal moves down slightly, the booster is in good condition. If there is no change, the booster is not operating.

   

3. 3
   With the engine running, depress the brake pedal, then stop the engine. Hold the pedal depressed for 30 seconds. If the pedal height does not change, the booster is in good condition; if the pedal rises, the booster is not operating. If the previous three tests were performed normally, booster performance can be judged as good. Even if one of the three tests above is not satisfactory, inspect the check valve, vacuum hose, and booster for malfunction.

   

Removal

1. 1
   Turn the ignition switch OFF and disconnect the negative (-) battery cable.
2. 2
   Remove the air duct (B) and the air cleaner assembly (A).

   

3. 3
   Disconnect the connector and loosen the wiring harness mounting nuts. Then move the wiring harness (A) aside so that it does not interfere.

   

4. 4
   Disconnect the brake fluid level switch connector (A) and remove the reservoir cap.

   

5. 5
   Remove the brake fluid from the master cylinder reservoir using a syringe.

   Do not spill brake fluid on the vehicle, as it may damage the paint. If brake fluid gets on the paint, wash it off immediately with water.

6. 6
   Remove the brake tube (A). Torque: ABS: 12.7 ~ 16.7 N·m ESP: 18.6 ~ 23 N·m

   

7. 7
   Remove the master cylinder (B) from the brake booster after first loosening the mounting nuts (A).

   Tightening torque: 9.8 ~ 15.6 N·m

   

8. 8
   Disconnect the vacuum hose (A) from the brake booster.

   

9. 9
   Remove the lock pin (B) and the flat-head pin (A).

   

10. 10
    Remove the mounting nuts.

    Tightening torque: 12.7 - 15.7 N·m

    

11. 11
    Disconnect the brake tubes from the HECU by turning the nuts (B) counterclockwise with a wrench.

    Tightening torque: 12.7 - 16.7 N·m

    

12. 12
    Remove the brake booster.

Inspection

1. 1
   Inspect the check valve in the vacuum hose.

   Do not remove the check valve from the vacuum hose.

2. 2
   Check the boot for damage.

Installation

1. 1
   Installation is the reverse of removal.

   • Before installing the pin, apply grease to the clevis pin.
   • When installing, use a new clip.
2. 2
   After installation, bleed the brake system. (Refer to Brake System Bleeding)