Air Supply System (very important)

Question 1

Air Leak Check

Answer 1

1. Shut off the engine. (on position)
2. Chock your wheels if necessary.
3. Place transmission in gear.
4. Release parking brake (yellow) and tractor protection valve (red) (push in).
5. Fully apply the foot brake, indicate starting pressure, and hold it for 1 minute.
6. Check the air gauge to see that the air pressure drops no more than 4 psi in 1 minute in a combination vehicle. Indicate ending pressure.

Question 2

Low-Air Warning Check

Answer 2

1. Ensure all brakes are still released (pushed in).
2. Turn the key to the “on” position without restarting the engine.
3. Begin fanning off the air pressure by pumping the foot brake.
4. Low-air warning light should activate at 55 psi or above. Indicate pressure level.

Question 3

Parking Brake/Tractor Protection Valve

Answer 3

1. Ensure all brakes are still released (pushed in).
2. Continue to fan off the air pressure.
3. When pressure drops to approx. 40 psi on a combination vehicle, the parking brake (yellow) and tractor protection valve (red) should close (pop out).