North Dakota CDL — Air Brakes Practice Test 8

1.Your brakes are very wet and the temperature is below freezing. What does the manual say can happen if you set the parking brakes now?

They can freeze up and leave the vehicle stuckThe spring brakes can release on their ownThe air tanks can lose all their pressureThe brake drums can crack from the cold

2.Your tractor has a dual air brake system and is hooked to a trailer. Which of the two systems does the manual say supplies air to the trailer?

Both systemsOnly the primary systemOnly the secondary systemNeither; the trailer has its own compressor

3.North Dakota's manual gives the low air warning test in two versions of its vehicle inspection test. Before what pressure should the warning devices activate in each version?

55 psi in the older three-component check; 60 psi in the modernized four-part check60 psi in both versions60 psi in the older three-component check; 55 psi in the modernized four-part check45 psi in the older three-component check; 60 psi in the modernized four-part check

4.North Dakota's manual says Class A, B and C drivers are restricted from air-brake-equipped commercial vehicles until they pass a knowledge test on air brakes plus a skill test. What kind of vehicle does it say the skill test must be taken in?

One that has a full or a partial air brake systemOnly a tractor-trailer with full air brakes on every axleAny commercial vehicle, whatever kind of brakes it hasA vehicle with hydraulic brakes, to prove the basics first

5.Many brake systems are built so that pressing the brake pedal while the spring brakes are on will not damage the brakes. Why does the manual still tell you to make a habit of staying off the pedal?

Pressing the pedal drains the separate parking air tankThe pedal releases the spring brakes on most vehiclesIt wears out the stop light switchSome systems lack that protection, and the protection can fail where it is fitted

6.Someone pulls out suddenly in front of you, and there is enough distance to stop. How does the manual say you should brake?

By locking all the wheels and holding them lockedBy pulling the parking brake knobSo the vehicle stays in a straight line and you can still turn if you have toBy tapping the pedal lightly to save air

7.The manual gives a separate air pressure buildup standard for single air systems on pre-1975 vehicles. Which matches its typical requirement?

85 psi up to 100 psi in 45 seconds, at idle speed50 psi up to 90 psi in 45 seconds, at operating rpm50 psi up to 90 psi in 3 minutes, at idle speed0 psi up to 125 psi in 3 minutes, at operating rpm

8.The ABS requirement for air-braked vehicles took effect on two different dates. Which vehicles does the manual say came first?

Trailers and dollies, built on or after March 1, 1997Truck tractors, built on or after March 1, 1997Buses, built on or after March 1, 1996None; every air-braked vehicle came under the rule on March 1, 1998

9.For the air brake check on North Dakota's vehicle inspection test, when does the manual say you will use wheel chocks?

Only when the test vehicle is a combinationOnly if the parking brake fails to holdNever; the parking brake stays set throughoutIn areas where there is an incline

10.In the modernized air leakage rate test, a straight truck is pulling a trailer that has no air brakes. With the foot brake held for one minute after the gauge stabilizes, what is the most the pressure may drop?

Two pounds, because part of the vehicle is not on airThree pounds, the same limit as a single vehicleFour pounds, the limit for a combination vehicleFive pounds, because the trailer adds length