Pic. 113. Brake pedal with vacuum booster and master cylinder: 1 - emergency liquid level sensor; 2 - tank; 3 - main cylinder; 4 - vacuum amplifier; 5 - pusher; 6 - brake pedal; 7 - brake light switch buffer; 8, 9 - brake light fastening nuts; 10 - stoplight switch; 11 - pedal return spring
If the brake light switch is too close to the pedal, it will not return to its original position. Valve 18 (see fig. 105), pressing against the body 21, separates the cavities A and B, and there is an incomplete release of the wheels when the pedal is released. If by moving the brake light switch it is not possible to eliminate the incomplete release of the brake mechanisms, then the master cylinder of the brake drive is disconnected from the vacuum booster and the protrusion of the adjusting screw 4 relative to the mounting plane of the master cylinder flange is checked (size 1.25 mm). This size is set by holding the end of the rod with a special key, and wrapping or unscrewing screw 4 with another key.