Checking the performance of the vacuum brake booster
With the engine off, increase the pressure in the brake booster to atmospheric pressure by pressing the brake pedal several times at intervals of about five seconds. Then start the engine with the brake pedal fully depressed. Make sure that when the vacuum increases to a normal value, the distance from the floor of the car to the brake pedal increases.
Leak test
Let the engine run at idle for approximately one minute to create a vacuum in the brake booster. Press the brake pedal several times at intervals of about five seconds to eliminate the vacuum in the amplifier. Make sure that with each subsequent press (A - B - C) the distance from the floor of the car to the lower position of the pedal gradually increases.
Depress the brake pedal with the engine running and stop the engine without releasing the pedal. The pedal must remain in the initial position for at least 30 seconds.
Note. When you fully depress the brake pedal, you may feel a slight jolt with a click. This is normal and does not indicate a malfunction.