36. With air brake vehicles, the parking brakes should be used:
Whenever you leave the vehicle unattended
37. A straight truck or bus air brake system should not leak at the rate of more than ____ psi per minute with the engine off and the brakes released.
2.
38. Which of these is NOT a proper time to apply the parking brakes?
To brake vehicle very hard, in other word when coming down the steep grade.
39. Which air brake vehicles, the parking brakes should be used:
Anytime when the vehicle is parked.
40. Why should you drain water from compressed air tanks?
Water can freeze in cold weather and cause brake failure.