| Daily | |
| Weekly | |
| Never | |
| Monthly |
| Allow water and oil to be expelled from air tanks | |
| Deliver air from the air tanks to the air brakes | |
| Allow excess air pressure to be released from air tanks | |
| Deliver air from the air compressor to the air tanks |
| Delivers air from the air compressor to the brakes | |
| Ensures that the air storage tanks are properly pressurized | |
| Captures air that has been delivered to the brakes but was unused | |
| Delivers air from the air storage tanks to the brakes |