North Dakota CDL — Air Brakes Practice Test 1

1.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

2.You release the brake pedal on a vehicle with s-cam brakes, and the s-cam rotates back. What draws the brake shoes back off the drum?

Air pressure in the brake chamberThe power screwA springThe slack adjuster's wedge

3.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

4.North Dakota's air brake check tells you to "fan off" the air pressure with the engine off and the key on. What does fanning off mean?

Pressing and releasing the foot brake quickly, over and overOpening the drain valve on each air tankPulling and pushing the parking brake knob repeatedlyHolding the foot brake down for a full minute

5.On a vehicle with automatic slack adjusters, a pushrod stroke beyond the legal adjustment limit points to one of several things. Which of these is NOT one the manual names?

A mechanical fault inside the adjusterTrouble in the foundation brake parts tied to that adjusterAn adjuster that was installed improperlyA governor cut-out pressure that is set too high

6.Only your tractor has ABS; the trailer does not. During hard braking, what does the manual tell you to keep an eye on?

The trailer, easing off the brakes if you safely can when it starts to swing outThe air gauge, releasing the brakes if the needle moves at allThe ABS lamp, braking harder each time it flashesThe tachometer, shifting to neutral if rpm drops

7.Braking creates friction and heat at the drum. What does the manual say determines how much heat a drum can take without damage?

Only the outside air temperatureHow many air tanks the vehicle carriesWhether the vehicle has ABSHow hard the brakes are applied and for how long

8.Compressed air usually carries some water and compressor oil. Where does the manual say they tend to collect, and what is fitted there?

In the brake chambers, where each has a relief portAt the governor, which has a built-in filterIn the bottom of the air tank, where each tank has a drain valveIn the foot valve, which vents them when you brake

9.According to the manual, how may an air compressor be cooled?

Only by a separate radiator of its ownBy air, or by the engine's cooling systemBy alcohol drawn from the evaporatorBy compressed air bled back from the storage tanks

10.Outside of brake maintenance and adjuster installation, when does the manual accept manually adjusting an automatic slack adjuster?

Every week, as routine upkeepOnly as a temporary measure in an emergencyWhenever the pushrod stroke looks longBefore every long downgrade