Start the engine and let's it work on single turns about 1 min. Muffle it, having given vacuum to the amplifier. Several times press a brake pedal with usual effort and produce the available vacuum. Make sure that when pressing a brake pedal the gap between a pedal of a brake and the panel of a floor gradually increases. Start the engine. Press a pedal of a brake and hold it pressed, then kill the engine. Take a pedal of the pressed about 30 Sealy more and be convinced that the course of a pedal does not change.