Recommendation. Inspection of pipelines and brake hoses is conveniently performed on an inspection ditch or overpass.
2. Carefully inspect the pipelines of the brake system for cracks, leaks of brake fluid.
3. We inspect the brake hoses for fatigue cracks, abrasions, blisters and leaks of brake fluid (see relevant sections below).
Comment. The front brake mechanisms are connected by hoses to tubes on the car body.
Two hoses connect tubes running along the bottom of the vehicle to tubes on the rear axle.
3. With the engine off, press the brake pedal several times until the hissing in the brake booster stops.
Comment. If the pedal «soft», possibly air in the hydraulic brake system. Bleed hydraulic brakes to remove air (see «Hydraulic brake drive - pumping»).
4. Press the brake pedal and take your foot off the pedal, the pedal should return to its original position.
5. Press the pedal and start the engine.
6. If immediately after starting the engine the pedal moves down a little, the brake booster is working.
7. Otherwise, we check the integrity of the vacuum supply hose to the vacuum booster 1, the tightness of the connection of the hose 2 with the inlet pipeline and the branch pipe of the check valve of the booster 3. Check the check valve.
Comment. 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.
Comment. If it feels like the pedal «malleable», then the system is not sealed. If a visual inspection fails to detect leaks of brake fluid and the brake fluid does not decrease, the most likely reason is that the brake master cylinder is faulty and needs to be replaced (see «Brake master cylinder - replacement»).