The working brake system consists of:
- master brake cylinder (hereinafter referred to as GTZ) with vacuum brake booster and hydraulic system expansion tank; four wheel brake cylinders;
- rigid hydraulic lines to the wheels;
- flexible hoses that supply pressure to the wheel cylinders.
The brake master cylinder is designed for use in diagonally split systems. One front and one diagonally opposed rear brake are served by a primary piston. The opposing front and rear brakes are served by a secondary piston. The brake master cylinder performs the functions of a standard dual master cylinder and also includes a low fluid indicator and limiter valves for non-ABS brakes. The limiter valves limit the pressure to the rear brakes when the master cylinder reaches a predetermined pressure,
The brake master cylinder is equipped with a fluid level sensor. This sensor switches on the power supply circuit of the BRAKE warning lamp when the brake fluid level in the reservoir is dangerously low.
The booster is a single diaphragm vacuum type booster. In the normal state, when the brake pedal is released, there is a vacuum on both sides of the vacuum booster diaphragm.
When the brake pedal is depressed, atmospheric air pressure is applied to one side of the diaphragm, providing boost. When the brake pedal is released, air is no longer supplied to that side of the diaphragm. Air is then vented from the booster through a vacuum valve.