Examination
1. To check the operation of the brake booster, depress the brake pedal several times to remove the vacuum in the system. With the pedal fully depressed, start the engine. When starting the engine, you should feel a noticeable "giveness" in the pedal as the vacuum increases. Let the engine run for at least two minutes and turn it off. If the brake pedal is now depressed, the pedal force will feel normal, but subsequent pedal presses should again result in an increase in pedal stiffness with a decrease in pedal travel with each press.
2. If the booster does not operate as described, first check the booster check valve as described in paragraph 12. On diesel engine models, also check the operation of the vacuum pump as described in paragraph 22.
3. If the brake booster still does not work satisfactorily, the fault lies in the brake booster itself. Its repair is impossible. If the brake booster is faulty, it should be replaced.
Removal
4. Disconnect the ground cable from the battery (see "Disconnecting the battery").
5. On left-hand drive models, remove the battery and battery tray. as described in chapter 5A. Depending on the model and work space, to facilitate access to the master cylinder, remove the air filter and the remaining components of the air intake duct as described in the relevant section chapter 4.
6. Remove the master cylinder as described in paragraph 10.
7. Release the clamp or press the tabs on the quick release coupling and disconnect the vacuum line from the brake booster check valve.
8. Remove the fuse box cover and the lower section of the driver's side fascia.
9. Remove the cotter pin and then remove the brake booster push rod mounting pin from the brake pedal. Please note that a new cotter pin will be required for installation.
10. Unscrew the four nuts securing the brake booster to the bulkhead.
11. Remove the brake booster from its standard position along with the gasket that is installed between the brake booster and the housing. Replace the gasket if it shows signs of damage.
Installation
12. Install the brake booster in its original location in the engine compartment.
13. From the passenger compartment side, screw on the vacuum booster mounting nuts and tighten them to the specified torque.
14. Insert the vacuum booster pushrod mounting pin to the brake pedal and secure it with a new cotter pin.
15. Install the fuse box cover and the lower section of the faceplate.
16. Connect the vacuum line to the brake booster check valve.
17. Install the master cylinder as described in paragraph 10, and then bleed the entire hydraulic drive as described in paragraph 2.
18. On left-hand drive models, install the battery tray and battery (refer to chapter 5A). Install the air filter and air intake duct components removed for access as described in the relevant section chapter 4.
19. Finally, connect the battery, start the engine and check for air leaks in the brake booster check valve.