Kentucky CDL — Air Brakes Practice Test 10

11.Describe the "stab braking" method for an emergency stop.

Hold the brakes locked until you stopPump the brakes gently and steadilyApply only the trailer brakesFully apply the brakes, release when the wheels lock, then reapply fully once they roll

12.After a loss of air, why does a heavily loaded vehicle need a long distance to stop once the spring brakes apply?

The engine cuts outThe spring brakes act on only some of the axlesThe steering wheel locks upThe tanks refill by themselves

13.How are the emergency and parking (spring) brakes held off while you drive?

Air pressure holds the powerful springs backThe driver keeps the pedal pressed downThe modulating valve holds them offHydraulic fluid keeps them released

14.Why is it important to drain the air storage tanks?

To remove the water and oil that collect inside themTo raise the maximum tank pressureTo refill the alcohol evaporatorTo reset the low-pressure warning signal

15.Does ABS shorten your stopping distance?

Not necessarily, but it helps you stay in control during hard brakingYes, it always cuts stopping distance in halfYes, but only on iceNo, it makes every stop longer

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

The combined spring and air forces could damage the brakesIt drains the alcohol evaporatorIt resets the ABS lampIt releases the parking brakes

17.Which statement about ABS and your normal brakes is correct?

It replaces your normal service brakesIt always shortens your stopping distanceIt works only while parkingIt is an add-on that does not change your normal braking ability

18.On a long, steep downgrade, the service brakes should be used in what role?

As the only way to slow the vehicleAs a supplement to the engine's braking effectOnly at the very bottom of the hillThey should never be touched on a downgrade

19.In an s-cam drum brake, what happens when you press the brake pedal?

Air enters the brake chamber and turns the s-cam so the shoes press against the drumA wedge is forced between the two brake shoesA power screw clamps a rotor between padsThe spring brakes release automatically

20.In a dual air system at operating rpm, pressure should climb from 85 to 100 psi within how long?

About 3 minutesAbout 10 secondsAbout 45 secondsAbout 2 minutes