Contents: Vacuum booster ↧ Checking the operation of the vacuum… ↧ Tightening torques for threaded… ↧
Vacuum booster
The vacuum booster uses a double diaphragm and a vacuum operating principle. In normal operation, when the brake pedal is not pressed, negative pressure acts on both sides of the diaphragm. When the pedal is pressed, one of the booster chambers is connected to the atmosphere and the resulting pressure creates additional force acting on the master cylinder piston. When the brake pedal is released, this chamber is disconnected from the atmosphere. Air is then sucked out of the booster through a vacuum check valve under the action of a vacuum.
Important: If any hydraulic component has been removed or disconnected during repair, it may be necessary to bleed the brake system completely or partially. See Part 4A. Hydraulic brakes.
Checking the operation of the vacuum booster
1. With the engine off, equalize the pressure in the booster vacuum chamber with atmospheric pressure. To do this, press the brake pedal several times.
2. Press the pedal and hold it in this position. Start the engine.
3. If the pedal continues to "fall through", it means that additional force is being applied to it, which indicates that the amplifier is working properly.
If the brake pedal does not sink, it may be the vacuum system (vacuum hoses, valve, etc.) is faulty and needs to be checked.
If the vacuum system check does not reveal a fault, then the amplifier itself is faulty.
Tightening torques for threaded connections
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Application
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N·m
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lb-ft
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lb-in
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Nuts securing the amplifier to the instrument panel
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22
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16
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(The original article is on the website: CHEVYMAN)