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. |
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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. |
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Step 2
PERFORMANCE ORDER |
1. Launch the engine. |
2. In 1–2 minutes stop the engine. |
3. Press a brake pedal with usual effort. |
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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. |
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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. |
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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. |
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If malfunction is still not eliminated, execute more detailed survey, using the manometer and the vacuum gage.