66. The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in the _____ brake line.
Emergency
67. When coupling, the proper position of the fifth wheel is:
Tilted down toward the end of the trailer.
68. What gear should the tractor engine be in after you uncouple the trailer and are inspecting the trailer supports?
Neutral.
69. When uncoupling the trailer, after you shut off the trailer air supply and lock the trailer brakes, you should:
Back you gently to ease pressure on the fifth wheel.
70. You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You expect the trailer brakes to come on and:
The tractor protection valve to close.