Table of contents: TO #30 ↓ Removal the brake booster ↓
TO #30
The engine must be turned off.
Press the brake pedal 10 times.
Now keep the brake pedal fully depressed and start the engine.
If the brake booster is working properly, the pedal should move slightly at this point. If this does not happen, then the brake booster is faulty.
Most likely, you should look for a fault in the vacuum system: a leaky vacuum hose from the intake manifold to the brake booster, a faulty check valve in the vacuum hose near the booster, a rubber ring between the master cylinder and the booster, or a booster membrane.
To check the check valve, disconnect the vacuum hose from the brake booster.
Blowing should be possible, but not suction.
The check valve can only be purchased together with the corresponding vacuum hose.
To replace a damaged rubber ring between the master brake cylinder and the booster, you need to remove the cylinder.
A faulty brake booster cannot be repaired. Replace.
Removal the brake booster
Remove the master brake cylinder.
Remove the vacuum hose.
Remove the shelf on the left under the dashboard, as well as the air duct (chapter "Salon").
Remove the pivot pin in the brake booster control rod fork head.
Remove the self-locking nuts securing the brake booster in the vehicle interior.
Then remove both nuts securing the brake booster in the engine compartment.
The distance between the center of the fork head hole and the supporting surface with four studs should be 230 mm (tolerance 0.5 mm).
After adjustment, tighten the lock nut securely.
Before installation, lubricate the pivot bolt with grease.
Use only a new pivot pin retainer and new self-locking nuts. Install a new O-ring between the brake booster and the brake master cylinder.
(The article was copied from the website AUDIMANUAL.RU)