The five main components of an elementary air brake system and their purposes are:
- Compressor: to build up and maintain air pressure
- Reservoirs: to store the compressed air
- Foot valve: to draw compressed air from reservoirs when it's needed for braking
- Brake chambers: to transfer the force of compressed air to mechanical linkages
- Brake shoes and drums or brake rotors and pads: to create the friction needed to stop the vehicle