Virginia CDL — Air Brakes Practice Test 7

1.The moment the low-pressure warning light and buzzer come on while you are driving, what should you do?

Keep driving until the spring brakes engage by themselvesBring the vehicle to a safe stop while you can still control the brakesPump the pedal quickly to rebuild pressureShift to a higher gear and speed up to the next exit

2.During the static air-leakage test on a single vehicle (engine off, parking brake released), the pressure loss should be no more than what?

Less than five psi in one minuteLess than two psi in one minuteLess than ten psi in one minuteLess than twenty psi in one minute

3.Around what pressure does the governor 'cut in' and let the compressor start pumping again?

About 125 psiAbout 20 psiAbout 150 psiAbout 100 psi

4.On newer air-brake vehicles, what does the parking-brake control usually look like and how is it used?

A yellow, diamond-shaped knob you pull out to apply and push in to releaseA round green button you tap onceA foot pedal to the left of the clutchA red octagonal knob you rotate a quarter turn

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

To lower the pressure so the governor can restTo remove collected water and oil that could freeze or damage the systemTo let fresh alcohol circulate through the linesTo reset the low-pressure warning device

6.While a truck is being driven normally, what holds the spring brakes in the released position?

A mechanical latch on the axleThe slack adjuster locking the camElectric current from the ABS moduleAir pressure holding the springs back

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

It could damage the brakes from the combined spring and air forcesIt instantly drains all the air from the tanksIt disables the ABS malfunction lampIt causes the governor to skip cut-out

8.What does a supply pressure gauge tell the driver?

How hard the brakes are being appliedHow much pressure is stored in the air tanksThe temperature of the brake drumsHow many miles remain before service

9.Which sequence correctly describes the stab braking method for an emergency stop?

Apply fully, release when the wheels lock, then reapply fully once they roll againHold steady light pressure the entire timePump the pedal rapidly without ever releasing fullyApply the parking brake instead of the pedal

10.How does an air-operated disc brake differ from an s-cam brake?

It uses a power screw and caliper to clamp a rotor instead of an s-camIt needs no air pressure to operateIt relies on a wedge driven between the shoesIt has no slack adjuster at all