With the engine stopped, depress the brake pedal normally, several times. The brake pedal must be depressed before the engine is started in order to remove vacuum from the booster.
With the brake pedal depressed start the engine. When the engine is started, vacuum is created and operates the booster. This causes the pedal to go down.
If the brake pedal goes down slightly, the booster is operating normally. If the brake pedal does not move, the booster is not receiving manifold vacuum, or is malfunctioning.
The brake booster is designed to create a greater braking force from minimum pedal effort, using a difference in atmospheric pressure and the engine's manifold vacuum. It increases the pedal force 2 to 4 times depending on the size of the diaphragm. The brake booster is located between the brake pedal and the master cylinder.
When pressure is applied to the brake pedal, pressure is exerted on the booster air valve. With pressure created by the booster the master cylinder is applied. Should the booster malfunction, the normal mechanical force of the master cylinder is maintained.
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Brake Booster Advantage
OE performance and reliability
Exclusive rust-prohibitive finishing process
Extends on-car and on-shelf life
Master Cylinder Output Rods are Pre-adjusted when included
Saves service dealer time and ensures easy and proper installation