CDL Test Air Brake Sample Practice Questions
1. Oil and water usually collect in compressed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks?
a. After every working day.
b. After every four hours of service.
c. Once a week.
d. Every other week.
2. What can legally hold a parking or emergency brake in position for a truck, truck tractor or bus?
a. Fluid pressure
b. Air pressure
c. Spring pressure
d. Any of the above
3. Air loss in a straight truck or bus should not be more than ____ with the engine off and the brakes on.
a. 1 psi in 30 seconds
b. 1 psi in one minute
c. 2 psi in 45 seconds
d. 3 psi in one minute
4. If the air compressor should develop a leak, what keeps the air in the tanks?
a. The tractor protection valve
b. The emergency relay valve
c. The one way check valve
d. The air compressor
5. The brake system that applies and releases the brakes when the driver uses the brake pedal is the:
a. Service brake system.
b. Emergency brake system.
c. Parking brake system.
d. None of the above.
CDL Test Air Brake Sample Practice Questions – download free
6. The driver must be able to see a warning that is given before air pressure in the service air tanks falls below:
a. 80 psi
b. 40 psi
c. 20 psi
d. 60 psi
7. The braking power of the spring brakes:
a. Can only be tested by highly trained brake service people.
b. Depends on the adjustment of the service brakes.
c. Increases when the service brakes are hot.
d. Is not affected by the condition of the service brakes.
8. The application pressure gauge shows the driver how much pressure:
a. Has been used on the trip.
b. Is in the air tanks.
c. None of these.
d. Is being applied to the brakes.
9. During normal driving, spring brakes are usually held back by:
a. Spring pressure
b. Bolts or clamps
c. Centrifugal force
d. Air pressure
10. The brake pedal in an air brake system:
a. Is to be used as a footrest during normal driving.
b. Controls the speed of the air compressor.
c. Controls the air pressure applied to put on the brakes.
d. Is connected to slack adjusters by a series of rods and linkages.
CDL – Commercial Drivers License Test Air Brake Sample Exam Questions.
11. If your truck or bus has dual parking control valves it means that you can use pressure from a separate tank to:
a. Balance the service brake system.
b. Release the spring brakes to move a short distance.
c. Stay parked without using up service air pressure.
d. Apply more brake pressure if the main tank is getting low.
12. 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. Continue at normal speed and find a garage before the brakes lock.
c. Reduce your speed and test the remaining system while under way.
d. Stop. Safely park, and continue only after the system is fixed.
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