To read an air brake schematic for a truck, you need to understand what the different components on the schematic represent. These components include the air compressor, valves, brake chambers, air dryer and reservoir tanks.
The air compressor is the part that supplies air into the brake system of the truck. By pumping air into the air reservoir tanks, it sets up a supply that then moves on into the other parts shown on the schematic. With the help of the air compressor governor, an air brake system can regulate the amount of air received by the tanks.
Reservoir tanks store the high pressure air that feeds the rest of the brake system. Once released from the tanks, this air passes through a series of valves. There are three types of valves in a truck’s air brake system: the foot valve, the safety valve and the check valve.
The foot valve performs the same function as a normal brake pedal. It releases air into the reservoir tanks when pressed, which slows down the truck. The safety valve prevents the system from experiencing excess pressure. It curtails excess air from passing through the rest of the passages. The check valve ensures that air produced by the reservoir tanks stays on a one way path towards the brake chambers.
The brake chambers are the interface between the truck’s axle and the brake system. They have flexible rubber diaphragms, which push against a pushrod that activates the brakes against the wheels of the vehicle.