At the working engine and the serviceable vacuum amplifier the brake pedal when braking should not reach a cab floor — the gap between a pedal and a floor has to be not less than 40 mm.

Efficiency of the vacuum amplifier is checked as follows: at the idle engine it is necessary to press a brake pedal 3 — 4 times, and then, by the subsequent pressing a pedal, holding it with effort of 300 — 400 N (30 — 40 kgfs), to launch the engine. At the serviceable amplifier the pedal will move to a floor a little, and hissing of the air passing through the filter of the amplifier will be heard.

If the pedal does not move or its movement is complicated, then the reason in malfunction of the amplifier or the wrong adjustment of the engine idling.

Serviceability of system of the alarm system of emergency falling of level of liquid in a tank of the main cylinder is checked by pressing a float core. At the same time on the dashboard the lamp of red color has to light up.