Air Brake Practice Test 2025 – All-in-One Resource to Master Your Certification!

The brake lining is the component primarily responsible for creating friction when the brakes are applied. This lining is made from a high-friction material that comes into contact with the brake drum (or brake disc, depending on the system type). When the brakes are engaged, hydraulic or air pressure forces the brake shoes (or pads) against the brake lining, which in turn presses against the surface of the brake drum. This contact generates the necessary friction to slow down or stop the vehicle.

The composition and condition of the brake lining are critical for effective braking performance, as they directly impact how much friction is produced. Well-maintained brake linings are essential for safe operation, ensuring that the vehicle can stop effectively in response to the driver's actions.

Other components like the brake drum serve as the surface against which the lining works but do not create friction themselves. The air compressor is essential for providing compressed air to actuate the brakes but does not create friction. The push rod is part of the linkage that transmits force from the brake actuator to the brake shoes but is not responsible for the friction needed to slow the vehicle.