| Trailer brakes | |
| Air brakes | |
| Emergency and parking brakes | |
| Cab brakes |
| Never | |
| Daily | |
| Weekly | |
| Monthly |
| Delivers air from the air storage tanks to the brakes | |
| Delivers air from the air compressor to the brakes | |
| Captures air that has been delivered to the brakes but was unused | |
| Ensures that the air storage tanks are properly pressurized |