What is the function of the brake chambers in an air brake system?

BRAKE CHAMBERS convert AIR PRESSURE into the MECHANICAL FORCE that applies the brakes at each wheel. CDL air brakes. When the driver presses the brake pedal, air pressure enters the brake chamber, pushing a diaphragm and pushrod, which moves the SLACK ADJUSTER and turns the cam (or wedge) to press the brake shoes against the drum (or pads against the rotor). The brake chamber is where air pressure becomes braking force. SLACK ADJUSTERS must be properly adjusted (out-of-adjustment brakes are a common violation and safety hazard). Knowing the brake chamber converts air pressure to mechanical braking force is commonly tested.