Necessary special tools and equipment
- Mot. 453-01 Hose clamp.
- Vacuum pump.
Tightening torques, Nm
- Vacuum booster mounting nut 18.
- Vacuum booster fastening nut on the bulkhead shield 23.
The vacuum booster cannot be repaired. It is allowed to carry out work related to the air filter and check valve.
Removing
1. Disconnect the wires from the battery and remove it.
2. Remove the brake master cylinder (follow the previously described method).
3. Remove the battery heat shield (4 bolts, 1 nut).
4. Remove two nuts of fastening of a broad tank and shift it towards the engine.
5. Disconnect the vacuum tube from the vacuum booster.
6. Remove in the passenger compartment:
- finger A from the fork connecting the brake pedal to the pusher, moving the clip;
- four nuts for fastening the vacuum booster;
- vacuum booster.
Installation
1. Before installation, check the dimensions: L = 104.8 mm and X = 22.3 mm.
2. Installation is made in an order, the return to removal.
3. Purge air from the hydraulic circuit.
Leak test
Attention! When checking the tightness of the vacuum booster, ensure the required tightness between the vacuum booster and the master brake cylinder. If there are leaks, replace O-ring A.
The tightness of the vacuum booster is checked on a vehicle with a hydraulic circuit in working condition.
1. Connect a vacuum pump between the vacuum booster and vacuum source (intake manifold) using a tee and the shortest possible tube.
2. Let the engine idle for one minute.
3. Pinch the tube with a clamp in the area between the tee and the vacuum source.
4. Turn off the engine.
5. If the vacuum drops by more than 33 mbar (25 mm. rt. Art.) within 15 seconds, there is a leak located:
- or in the check valve (replace it);
- or in the piston diaphragm (replace vacuum booster).
6. If the vacuum booster is not working, then the brake system will work, but the force applied to the pedal to obtain deceleration, as with a running booster, will be much greater.
Air filter replacement
1. To replace the air filter F, it is not necessary to remove the vacuum booster.
2. Remove the dirty filter from the bottom of the pedal mounting bracket with a screwdriver or a metal hook.
3. Cut a new filter in area A and install it around the push rod.
4. Then press it into place, checking that the filter completely fills the hole, thus excluding the penetration of unfiltered air into the vacuum booster.
Check valve replacement
1. The operation can be carried out by car.
2. Disconnect the vacuum tube from the vacuum booster.
3. Pull the check valve out by rotating it out of the rubber sealing washer.
4. Check the condition of the rubber sealing washer and check valve.
5. Replace defective parts.
6. Replace the assembly.