Nevada CDL — Air Brakes Practice Test 3

1.Air needs time to flow through the lines before air brakes apply. About how long does that delay usually take?

About one-tenth of a secondAbout three secondsAbout five secondsHalf a second or more

2.The first part of the air brake check on the CDL vehicle inspection test is the air gauge and governor cut-off check. What does it involve?

Chocking the wheels, starting the vehicle, confirming the gauge works as pressure rises to cut-off, and naming your vehicle's cut-off pressureHolding the foot brake down for one minute with the engine offFanning the brake pedal until the low air warning devices activatePulling gently against the parking brake in a low gear

3.On your walk-around, you find a brake fitted with an automatic slack adjuster that is out of adjustment. What does the manual recommend?

Back the adjuster off so the brake drags lessLeave it, since it will correct itself on the next hard stopAdjust it by hand and treat the matter as fixedTake the vehicle to a repair shop promptly so the fault can be fixed

4.During your pre-trip leakage test, the air pressure falls faster than the allowed rate. What does the manual say to do, and why?

Drive gently to the next shop, since leaks only matter under hard brakingFind and fix the leaks before driving, or you could lose your brakes on the roadDrain the air tanks and run the test again until it passesRaise the governor cut-out pressure to make up for the leak

5.You open the valve on a manually drained air tank at the end of the day. How much should you let out?

Only a quick burst, so you don't lose any working pressureJust enough to hear air escaping, then close the valveNone while the tank is cold; wait until the next morningDrain the tank completely so the water and oil are removed

6.Some buses have dual parking control valves fed by a separate air tank. What is that separate tank there to do?

Keep the service brakes working normally after main air is lostRelease the spring brakes so the bus can be moved in an emergency after main air is lostSupply air to the horn and wipers when the compressor stopsRefill the main tanks when the governor fails

7.An air brake system is really three braking systems in one. Which pairing of a system with the thing that puts it to work is correct?

Service brake system: the parking brake control in the cabEmergency brake system: a separate set of brakes held in reserve for emergenciesParking brake system: the brake pedal during normal drivingParking brake system: the parking brake control in the cab

8.You switch from a fleet truck with two air storage tanks to one that has three larger tanks. What does the manual say about a difference like this?

It is normal; the number and size of air tanks vary from vehicle to vehicleEvery air-braked vehicle must carry exactly two tanks of equal sizeA truck with three tanks does not need an air compressorLarger tanks never collect water, so they never need draining

9.On a newer air-braked truck, what does the parking brake control look like, and how do you set the brakes with it?

A round blue knob; push it in to set the brakesA red, eight-sided knob; give it a quarter turn to set the brakesA yellow, diamond-shaped knob; push it in to set the brakesA yellow, diamond-shaped knob; pull it out to set the brakes

10.A dual air brake system is really two separate air brake systems. How does the driver work them?

With a separate brake pedal for each systemWith one pedal for normal driving and a hand valve for the second systemBy switching between the two systems with a dash selectorWith a single set of brake controls that serves both systems