Alabama CDL — Air Brakes Practice Test 1

11.Why should you avoid pressing the brake pedal while the spring brakes are already applied?

It instantly drains all the air tanksThe combined forces can damage the brakesIt disables the low air warning deviceIt permanently releases the parking brakes

12.Your brakes have gotten soaked. How does the manual suggest you dry them out?

Roll along in a low gear and apply light brake pressure to warm themPark the truck and wait for the water to evaporate on its ownHold the parking brakes on hard for several minutesPump the pedal rapidly while the vehicle sits still

13.For a vehicle with air brakes, total stopping distance is made up of which four parts?

Perception, reaction, cornering, and coasting distanceFollowing, merging, braking, and reaction distancePerception, reaction, brake lag, and braking distanceIdle, cut-in, cut-out, and braking distance

14.If one half of a dual air system loses most of its pressure, what should you expect?

The parking brakes will release automaticallyThe remaining system will double its powerIt will take longer to stop the vehicleThe brakes will lock up immediately

15.How do antilock brakes (ABS) help you during hard braking?

They always shorten your stopping distance by halfThey apply the parking brakes for you automaticallyThey help prevent wheel lockup so you can keep steeringThey replace the need for the service brakes entirely

16.Why is it important to drain the air tanks completely?

To let the compressor cool down between stopsTo lower the pressure so the governor can resetTo add fresh alcohol to the braking systemTo remove water and oil that could cause brake failure

17.When using the 'controlled braking' method in an emergency, how hard should you press the brakes?

As hard as you can without locking the wheelsOnly lightly, so the wheels never slowHard enough to lock the wheels and hold themIn quick full-pressure pulses only

18.How is the air compressor typically driven?

By exhaust gases passing through a turbineThrough gears or a v-belt tied to the engineBy an independent electric motorBy the rotation of the drive axle only

19.When checking a slack adjuster on an s-cam brake by hand, how much movement suggests it probably needs adjustment?

More than about one inch of movementAny movement at all, even a fraction of an inchMore than about six inches of movementOnly if it does not move whatsoever

20.When the low air pressure warning first comes on, what is the safest thing to do?

Keep driving until the spring brakes apply themselvesPump the pedal rapidly to rebuild pressureSpeed up to reach the next exit soonerBring the vehicle to a safe stop right away