Examination
1. To check the operation of the vacuum booster, press the brake pedal several times. Then, without releasing the pedal, start the engine. When the engine starts, the pedal should "go forward" and you should feel the pedal weaken. Let the engine run for at least two minutes, then turn off the ignition. In order to press the pedal, you should need normal force, but with further pressing, the pedal should become "tighter" and with each press, the pedal travel should decrease.
2. If the booster does not operate as described, first check the vacuum valve as described in paragraph 12.
3. If after checking the valve the booster does not work, the fault is in the vacuum booster itself. The booster cannot be repaired - if faulty, replace it entirely.
Removal
Note: New mounting nuts will be required during installation.
4. Remove the brake master cylinder as described in paragraph 11.
5. Loosen the mounting nut and disconnect the vacuum hose from the vacuum booster; see paragraph 12.
6. Remove the lower panel from the driver's side instrument panel as described in Chapter 11.
7. Remove the cotter pin and push out the pin securing the brake pedal to the vacuum booster pushrod.
8. Loosen and remove the four brake booster mounting nuts, then return to the engine bay and remove the brake booster from the vehicle.
Installation
9. Before installation, check the condition of the gasket that is glued to the back of the vacuum booster. If the gasket shows signs of wear or damage, cut it off and glue a new one.
10. Install the vacuum booster back into place in the engine compartment.
11. Working from inside the vehicle, align the brake booster pushrod with the brake pedal, then install and tighten the brake booster mounting nuts to the required torque.
12. Apply a layer of plastic grease to the vacuum booster push rod pin and secure it with a cotter pin.
13. Install the lower part of the instrument panel on the driver's side (see Chapter 11).
14. Connect the vacuum hose to the booster and tighten the mounting nut to the required torque.
15. Install the master cylinder as described in paragraph 10. When finished, start the engine and eliminate air leaks in the vacuum hose connections to the booster; check the operation of the braking system while driving.