Nevada CDL — Air Brakes Practice Test 7

1.You have to brake hard on a slippery road in a truck with working ABS. Which result can you reasonably expect ABS to help with?

Stopping in about half the usual distanceBraking with more force than your normal brakes could giveKeeping the brakes working after the air pressure is goneAvoiding a skid caused by braking too hard

2.In Nevada's suggested air brake check, you have built pressure to cut-out, shut off the engine with the ignition on, and released the tractor and trailer parking brakes. What comes next?

Pump the pedal rapidly until the parking brake knob pops outRestart the engine and run it at a fast idleOpen the tank drain valves to check for waterApply the foot valve and hold it for one minute

3.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

4.Over one week you drive three tractor-trailers: one with ABS only on the tractor, one with ABS only on the trailer, and one with ABS on both. How should your braking technique change from rig to rig?

It shouldn't; brake the same way, using only enough force to stop safely and keep controlBrake harder on the rig with ABS on both units, since it cannot skidPump the brakes on the rig with ABS on the tractor onlyUse the trailer hand valve alone on the rig with ABS on the trailer only

5.In a typical dual air brake truck, you notice the secondary system's pressure sinking while the primary holds steady. Which brakes are probably not working fully, and what should you expect?

The front-axle brakes; it will take you longer to stopThe rear-axle brakes; your stopping distance will not changeEvery brake on the truck; it will stop instantlyOnly the trailer brakes; the tractor will stop as usual

6.Which sequence matches the manual's service brake test for an air-braked vehicle?

Set the parking brake, raise the engine speed, and press the pedal lightly to see if the vehicle creepsLet pressure build to normal, release the parking brake, creep ahead at about 5 mph, and brake firmly with the pedalReach highway speed, then brake as hard as possible to see whether the wheels lockShut off the engine, release the parking brake, and pump the pedal until the warning comes on

7.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

8.During the service brake test, you creep forward at about 5 mph and brake firmly with the pedal. Which of these should you be watching for?

The low air warning coming on as you stopThe truck pulling to one side, an odd feel, or slow stoppingThe spring brakes popping on as the truck stopsThe governor cutting the compressor back in

9.While driving, you glance at your supply gauge and see it reading 50 psi, yet no low air warning of any kind has come on. What does this tell you?

Nothing is wrong; the warning is meant to come on at about 20 psiThe warning has failed, because it should have come on before pressure fell below 55 psiThe gauge must be broken, because tank pressure never drops below 100 psiThe warning waits for the governor cut-in point before it turns on

10.On a newer tractor, the ABS malfunction lamp does its start-up bulb check but then stays lit instead of going out. What may this mean?

Your normal service brakes have stopped workingThe spring brakes are about to applyABS may no longer be working at one or more wheelsNothing; the lamp always stays on until the air is fully built up