Vacuum booster: 1 - pusher; 2 - protective cover with a filter; 3 - stud for fastening the vacuum booster; 4 - amplifier case
Tightening torques:
- Brake master cylinder nuts - 18 Nm
- Vacuum booster nuts - 23 Nm
The vacuum brake booster cannot be repaired. During operation, the air filter of the amplifier and the check valve are replaced.
Removing
1. Disconnect and remove the battery.
2. Remove the main brake cylinder.
3. Turn away four bolts and one nut of fastening of protection of the storage battery, remove protection.
4. Turn away two nuts of fastening of a broad tank, remove a tank and fix it aside.
5. Disconnect the vacuum hose from the vacuum booster.
6. Box:
- remove the clip (A) fixing the brake pedal finger on the booster rod;
- unscrew the four nuts securing the amplifier.
Figure 7.21. Connection unit of the brake pedal with the fork of the pusher of the vacuum brake booster (the arrow shows the axis of the fork)
7. Remove the amplifier from a motor compartment.
Figure 7.22. Before installation, check the length of the rod L (104.8 mm) and pusher X (22.3 mm).
- check the adjustment dimensions of the amplifier (Figure 7.22) and restore them if necessary.
Installation
Installation is carried out in the reverse order of removal.
Remove air from a drive of brake system.
Amplifier check
Without starting the engine, press the brake pedal several times to remove the vacuum in the booster chamber and, holding the pedal fully depressed, start the engine. While the engine is running, the brake pedal should lightly «fall through», this means that the vacuum brake booster is working properly.
If the pedal «does not fail», you should check the air filter of the amplifier. To do this, in the passenger compartment at the brake pedal, remove the rubber cover at the rear of the amplifier and slide the cover along the stem.
Figure 7.23. Replacing the brake booster air filter: A - air filter notch zone; F - air filter installation location
To replace the filter, it is not necessary to remove the vacuum booster: under the support of the control pedals, use a screwdriver or a metal hook to remove the old filter (F).
in the new filter (A) make a radial cut and put the filter on the vacuum booster rod. Put the filter in place and straighten it.
Using a screwdriver, referring to Figure 7.23, remove the old air filter. Then, making a cut in the new filter, install it in place, making sure that it covers all the holes. Replace the rubber cover and check the amplifier again.
Figure 7.24. Brake Booster Check Valve: 1 - valve; 2 - rubber seal
If the result is unsatisfactory, try replacing the booster check valve. To do this, disconnect the vacuum hose from the vacuum booster. Pull out check valve (Figure 7.24), rotating it to remove it from the rubber seal.
Blow out the valve, air should flow only in one direction - from the side of the amplifier. If the valve does not purge or purges in both directions, replace it. Check the condition of the rubber seal. Assemble the assembly, attach the vacuum hose and check the operation of the amplifier.
If the amplifier does not work again, replace it, as the company does not supply a repair kit for parts.
Seal check
Special fixtures:
- Pressure gauge and adapters - Mot. 1311-01
1. Check up a condition of consolidation between the main brake cylinder and the vacuum amplifier.
If there are signs of leakage, replace the seal, see "Master brake cylinder".
2. Install pressure gauge Mot. 1311-01 between vacuum booster and intake manifold:
- A) Remove the vacuum hose.
- b) Put on the check valve fitting (1) technological piece of hose.
- V) Fasten with clamps (2) adapter (IN) from the set Mot. 1311-01.
- G) Connect the pressure gauge hose to the intake manifold fitting. The pressure gauge valve must be located on the side of the intake manifold. Open the faucet.
3. Run the engine to idle for one minute.
4. Close the pressure gauge valve and turn off the engine.
5. The pressure gauge should register a vacuum of the order of 613 mbar. If the vacuum decreases at a rate greater than 33 mbar in 15 seconds, then there are leaks in the system (either in the check valve or in the amplifier itself). If the amplifier is leaking, replace it as an assembly.