Class 1A Truck and Trailer Air Tests

Class 1A Air Tests

1. Chock wheels.
2. Drain air tanks.
3. Start engine, low air pressure alarm should go out minimum 60 psi.
4. Pressure should build from 85 to 100 psi in less than two minutes at max 800 rpm.
5. Governor should cut out compressor between 120 and 145 psi.
6. Push both valves in, governor should cut in compressor at minimum 100 psi.
   • slowly fan brakes if necessary
7. Air up to max pressure, shut down engine.
8. Check tractor protection system:
   1. Break service line, should be no air loss.
   2. Break supply line, should be no air loss from trailer, trailer brakes should dynamite, and air loss from tractor should stop at a minimum of 20 psi.
   3. Check that slack adjusters on trailer are about 90 degrees to pushrods (if drum brakes).
   4. After air loss stops, check that
      1. trailer supply valve popped, tractor park brake valve has not popped
      2. key on and check air pressure is above 20 psi
      3. no air loss on full brake application
      4. if trailer has disc brakes, start engine and tug on trailer to ensure brakes dynamited
   5. Connect air lines.
9. Start engine, supply trailer after alarm stops.
10. Build air to max pressure, shut down engine, turn key on.
11. Air leakage test:
    • make full brake application for one minute, should be no more than 4 psi loss after application.
12. Fan brakes, low air pressure alarm should come on at minimum 60 psi.
13. Fan brakes, trailer supply valve should pop out at minimum 20 psi, tractor park brake valve doesn't have to pop, but tractor park brakes must apply at minimum 20 psi.
14. Start engine, do immediate tug.
    • if park brake valve did not pop, pull it out now
15. Pick up chocks.
16. Supply trailer after alarm stops.
17. At minimum 100 psi
    1. do another tug
    2. pop trailer valve, release tractor brakes, tug
    3. supply trailer and roll ahead, then pull spike to stop
    4. roll ahead, use brake pedal to stop.
18. Air tests complete! Finish paperwork and drive!