Virtually all cars today use a vacuum brake booster system that multiplies the braking force and reduces the pedal effort. Since vacuum is always available when the engine is running, the system is simple and effective. A vacuum diaphragm is located in front of the master cylinder and assists the driver in applying the brakes by reducing the force and travel required to press the brake pedal.
The vacuum diaphragm housing is connected to the intake manifold by a vacuum hose. Where the hose enters the diaphragm housing is a check valve that prevents the brake from weakening during low manifold vacuum.
Pressing the brake pedal closes the vacuum sources and allows atmospheric pressure to enter one side of the diaphragm. This causes the master cylinder pistons to move and apply the brakes. When the brake pedal is released, vacuum is released to both sides of the diaphragm and springs return the diaphragm and master cylinder pistons to their original positions.
If the vacuum supply is lost, the brake pedal rod will contact the master cylinder actuator rod and the driver can apply the brakes without any power assist. Note that it takes much more pedal force to stop the car and that the pedal feels "heavier" than normal.
Brake booster — description (Honda Accord 3)
This article is available at: russian, bulgarian, belarusian, ukrainian, serbian, croatian, romanian, polish, slovak, hungarian
This information has been verified: Yaroslav Shiryaev
Link in different formats to this article
Comments and feedback from visitors
No comments yet
- General information
- Introduction to the guide
- User manual
- Maintenance
- Power unit
- Four-cylinder engines
- Six-cylinder engines
- Engine overhaul
- Cooling system
- Heater and air conditioner
- Power and exhaust systems
- Engine electrical equipment
- Engine management
- Transmission
- Mechanical gearbox
- Automatic gearbox
- Clutch and drive shafts
- Chassis and running gear
- Brake system
- Car suspension
- Steering
- Body and interior
- Exterior (external elements)
- Interior (internal elements)
- Electrical equipment
- Equipment and devices
- Electrical circuits
- General information
- Maintenance
- Power unit
- Engine adjustment
- Engine repair
- Engine electrics
- Emission management
- Engine management (carburetor)
- Electronic injection
- Programmable injection
- Schematic of emission system
- Fuel system
- Feedback management
- Transmission
- Manual gearbox
- Automatic gearbox
- Clutch
- Chassis and running gear
- Front suspension
- Rear suspension
- Steering
- Brake system
- Electrical equipment
- Ventilation and heating
- Air conditioner
- Cruise control system
- Equipment and devices