Air Brake Test

This video was made by CDL Test Truck they have produced several instructional videos that can be viewed on their YouTube channel.

The Air Brake check is designed to test the governor cut-in and cut-out pressures, air pressure leakage, warning buzzer, brake valves and air pressure rebuild rates.

  • Step 1. Put your seat belt on.
  • Step 2. Safe start vehicle (brakes set and vehicle in neutral), and build up air to operating pressure if needed.
  • Step 3. Select first gear, with wheel chocks down, Turn engine off and ignition switch back to the on position (but don't start the truck), release parking brakes, static test for leaks (check for air loss without applying any brakes) no more than 2 psi straight truck or 3 psi combination vehicle in 1 min.
  • Step 4. Press and hold foot pedal, ( 90 psi ) pedal pressure check that no more than 3 psi straight truck or 4 psi combination vehicle loss in your air pressure in 1 min (60 sec).
  • Step 5. Pump down the brake pedal to check that the air warning??? light/devise come on by 60 psi.
  • Step 6. After that. continue to pump down the brake pedal, check that the tractor protection valve pops out by 20 psi. which will apply tractor parking brake.
  • Step 7. Then put truck in neutral and start vehicle, we want to see how fast it takes for the air pressure to build back up. Check that air builds from??? 85 psi to 100 psi in under 45 seconds, and then continue to build air till air governor blows at approx 125-130 psi the air gauge will stop building pressure at this point.
  • Step 8. Continue with the brake check , release tractor brake, pull against trailer brake (Trolley brake).
  • Step 9. Set tractor brake, release trailer brake place truck in first gear and slightly release clutch to test tractor parking brakes.
  • Step 10. Release parking brakes, pull forward 5 mph hands above (but not touching) steering wheel apply foot brake, check for brakes pulling to left or right.
  • Step 11. Drive forward again 5 mph apply trailer hand valve (Trolley Brake Handle) to test trailer service brakes.
  • Step 12. Set parking brakes build to system to operating pressure prior to driving away.