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14.8. Check of the vacuum amplifier of brakes

Step 1

PERFORMANCE ORDER
1. At the switched-off engine, several times press a brake pedal.
2. Launch the engine.
3. If the pedal of a brake moves down at once after launch of the engine, it demonstrates normal operation of the vacuum amplifier of brakes.

Step 2

PERFORMANCE ORDER
1. Launch the engine.
2. In 1–2 minutes stop the engine.
3. Press a brake pedal with usual effort.
4. If the first course of a pedal – the long and second course, is shorter than the first course, it demonstrates normal operation of the vacuum amplifier of brakes.
5. Otherwise check the unilateral vacuum valve or a vacuum hose for absence of damage and check reliability of their fastenings.

Step 3

PERFORMANCE ORDER
1. Launch the engine.
2. Press a brake pedal with usual effort.
3. Stop the engine.
4. Slowly press a brake pedal, and hold it pressed within 30 seconds.
5. If height of a pedal does not change, the vacuum amplifier of brakes works normally.
6. Otherwise check the unilateral vacuum valve or a vacuum hose for absence of damage and check reliability of their fastenings.

If malfunction is still not eliminated, execute more detailed survey, using the manometer and the vacuum gage.