Colorado CDL — Air Brakes Practice Test 2

1.What should you always do before leaving your vehicle unattended?

Leave it in neutral with the brakes releasedDrain the tanks completely firstRev the engine to build pressureApply the parking brakes or chock the wheels

2.The low-air warning light and buzzer have just come on. What should you do?

Keep driving until the spring brakes apply themselvesStop safely right away while you still have brake controlPump the brake pedal to raise the pressureRelease the parking brake and speed up

3.On a long, steep downgrade, how should you think about your brakes?

As the only thing keeping you from running awayAs a supplement to the braking effect of the engineAs a reason to shift into neutral and coastAs a replacement for choosing a low gear

4.When testing the low pressure warning signal, before what pressure must the warning turn on?

Before pressure drops below 55 psiBefore pressure drops below 20 psiOnly after the spring brakes applyBefore pressure reaches 125 psi

5.During a walk-around, how much movement in a manual slack adjuster suggests it needs adjustment?

Any movement at allMore than a quarter inchMore than about one inchMore than three inches

6.On a vehicle with dual parking control valves and a separate air tank, what limits how you use it to move after the main air is lost?

It only works while the engine is offThe separate tank holds only enough air for a few releasesIt can only be used above 55 mphIt disables the service brakes while in use

7.Why are the air storage tanks important if the compressor suddenly quits working?

They cool the compressed air before it reaches the brakesThey automatically restart a failed compressorThey warn you the compressor has stoppedThey store enough air to apply the brakes several more times

8.What is the controlled braking method for an emergency stop?

Pumping the pedal in a steady rhythmSteering hard while releasing all brake pressureLocking the wheels and holding them lockedBraking as hard as possible without locking the wheels

9.In an air brake system, what does the air compressor do?

It pumps air into the storage tanks that supply the brakesIt warns the driver whenever tank pressure drops too lowIt converts stored air back into engine powerIt removes moisture and oil from the tanks automatically

10.If your air tanks have manually operated drain valves, how often should you drain them?

Only when the low air warning comes onAt the end of each day of drivingAbout once a monthOnly during freezing weather