Examination
1. To check the operation of the vacuum 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 «compliance» pedals 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 force on the pedal will be perceived as normal, but subsequent pedal strokes again should result in an increase in pedal stiffness with a decrease in pedal travel with each press.
2. If the amplifier does not operate as described, first check the amplifier check valve as described in paragraph 12. On diesel 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 itself. Its repair is impossible. If the vacuum brake booster is defective, it must be replaced.
Removing
4. Disconnect the wire «masses» from 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 operating space, remove the air filter and the remaining air intake piping as described in the appropriate part to facilitate access to the master cylinder chapter 4.
6. Remove the master cylinder as described in paragraph 10.
7. Release the clamp or press the tabs on the quick coupling and disconnect the vacuum line from the brake booster check valve.
8. Remove the fuse box cover and the lower section of the front panel on the driver's side.
9. Remove the cotter pin, and then remove the brake booster pusher pin to the brake pedal. Keep in mind that a new cotter pin will be required for installation.
10. Turn away four nuts of fastening of the vacuum amplifier of brakes to a partition.
11. Remove the vacuum brake booster from its original position along with the gasket that is installed between the vacuum booster and the housing. Replace gasket if it shows signs of damage.
Installation
12. Install the vacuum brake booster in its original place in the engine compartment.
13. From the cabin side, screw the vacuum booster mounting nuts and tighten them to the prescribed torque.
14. Insert a finger of fastening of a pusher of the vacuum amplifier to a brake pedal and fix it with a new cotter pin.
15. Install the fuse box cover and bottom section of the front panel.
16. Connect the vacuum pipeline to the check valve of the vacuum amplifier of brakes.
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 (if necessary, contact chapter 5A). Install the air filter and air intake piping removed for access as described in the appropriate part chapter 4.
19. Finally, connect the battery, start the engine and check for air leaks in the brake booster check valve.