Recommendation. It is convenient to inspect pipelines and brake hoses on an inspection pit or overpass.
2. Carefully inspect the brake system pipes for cracks and brake fluid leaks.
3. Inspect the brake hoses for fatigue cracks, abrasions, swelling and brake fluid leaks (see below for relevant sections).
Note: The front brake mechanisms are connected by hoses to tubes on the car body.
Two hoses connect the tubes running along the bottom of the car to the tubes on the rear axle.
3. With the engine not running, press the brake pedal several times until the hissing sound in the brake booster stops.
Note: If the pedal is "soft", there may be air in the brake hydraulic system. To remove air, bleed the brake hydraulic system (see "Hydraulic brake drive - bleeding").
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4. Press the brake pedal and remove your foot from the pedal, the pedal should return to its original position.
5. Press the pedal and start the engine.
6. If the pedal moves down slightly immediately after starting the engine, the brake booster is working properly.
7. Otherwise, check the integrity of the vacuum supply hose to the vacuum booster 1, the tightness of the connection of hose 2 with the inlet pipe and the branch pipe of the check valve of the booster 3. Check the check valve.
Note: If the hose, tube and valve are in good condition and the connections are tight, then the vacuum booster is faulty.
8. Press the brake pedal and, holding it down, turn off the engine. While holding the brake pedal, make sure that its position does not change for at least 30 seconds.
9. By pressing the brake pedal several times with a 5-second delay, we release the vacuum from the vacuum booster (see above, point 2). At the same time, we make sure that with each press the distance from the brake pedal to the floor increases.
Note: If the pedal feels "giveable", the system is not sealed. If a visual inspection does not reveal any brake fluid leaks and the brake fluid does not decrease, the most likely cause is that the brake master cylinder is faulty and must be replaced (see "Master Brake Cylinder - Replacement").