23. During normal driving spring brakes are usually held back by:
a. bolts.
b. air pressure.
c. spring pressure.
d. centrifugal force.
24. In air brake vehicles, the parking brakes should be used:
a. as little as possible.
b. any time the vehicle is parked or unattended.
c. to hold your speed when going downhill.
d. only during pre-trip and post-trip inspections.
25. Emergency stab braking is when you:
a. press hard on the brake pedal and apply full hand valve until you stop.
b. apply the hand valve for one second, then push hard on the pedal.
c. use light steady pressure on the brake pedal.
d. brake as hard as you can, release the brakes when the wheels lock, put on the brakes again when the wheels start rolling.
26. The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
a. 1 psi in 30 seconds.
b. 1 psi in one minute.
c. 2 psi in 45 seconds.
d. 3 psi in one minute.
27. The supply pressure gauge shows how much pressure:
a. you have used in this trip.
b. is in the air tanks.
c. is going to the brake chambers.
d. the air can take.
28. The brake system that applies and releases the brakes when the driver uses the brake pedal is the _____ brake system.
a. emergency.
b. service.
c. parking.
d. none of the above.
29. Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?
a. Reduce your speed, and drive to the nearest garage for repairs.
b. Reduce your speed, and test the remaining system while under way.
c. Continue at a normal speed. No action is needed when only one system fails.
d. Stop right away and safely park. Continue only after the system is fixed.
Page 4 answers: (23)b (24)b (25)d (26)d (27)b (28)b (29)d
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