They are often also called brake pads, and are a critical component of braking systems as they are the material which comes into contact with the rotors in order to slow them down without wearing them out too quickly.
Brake lining material is attached to metal backing, such as a brake shoe, usually with heat-resistant rivets or joints. The lining comes into contact with the rotors creating enough friction to slow them down. The brake lining protects the rotors from coming into direct contact with the metal backing. This prevents them from wearing out quickly and needing frequent replacing.
Linings made from harder brake materials can cause accelerated wear and tear on the rotors or drums, and therefore it is important to check the quality and the suitability of the material with relation to the specifics of the system. Braking linings are used in the braking systems in machines, vehicles, appliances and elevators and thus can range from large heavy duty materials to lighter, softer linings.
As the kinetic energy of the braking process is turned into heat energy, the material used for brake lining purposes usually has a high coefficient of friction. Asbestos used to be the element most commonly used for brake linings, but the dust created by asbestos is harmful when inhaled, therefore, alternatives have been developed, such as aramid fibers which are now commonly used in braking components. Brake linings, like brake bands and brake blocks, need to be made from durable materials which are able to endure high levels of heat and pressure. The friction created is an essential element of the braking process and allows machinery and engines to speed up and slow down relatively quickly.
Brake linings will need to be replaced periodically as the material will inevitably be affected by wear and tear over time. Often the brakes will squeak or become less smooth as the lining wears out, this is important to pay attention to as worn out brake linings can cause greater, and more expensive, engine damage. In systems with multiple brake linings, it is important to replace or repair the corresponding linings at the same time. This is necessary to help achieve even and consistent braking within the system.