Kansas CDL — Air Brakes Practice Test 4

1.During the final air brake check, how does the manual have you confirm that the parking brake will actually hold the vehicle?

Set it, then rev the engine in neutral while watching the air gaugeSet it, then press the service brake pedal to see whether it feels firmPull gently against it in a low gear with the vehicle stopped and the parking brake onDrain the air tanks and watch whether the parking brake knob pops out

2.During the walk-around you tug firmly on each slack adjuster you can reach on the s-cam brakes. Movement beyond roughly how much, measured at the push rod connection, suggests the brake needs adjusting?

About a quarter of an inchAbout one inchAbout three inchesAny movement at all

3.In a drum-type foundation brake, what actually slows the wheel?

Air pressure pressing directly on the wheel rimFriction from the shoes and linings pressing on the drum's inner surfaceA wedge that locks the axle so it cannot turnPads that squeeze the outside of the tire

4.Automatic slack adjusters adjust themselves. When does that self-adjustment take place?

Each time the engine is startedDuring full brake applicationsOnly while the parking brake is setWhenever the governor cuts the compressor back in

5.On a long downgrade you keep leaning on the service brakes even after they start to fade. Where can that lead?

The ABS will take over and cool the brakesThe fade will stop once the drums finish expandingThe fade can keep growing until you can no longer slow or stop the vehicleThe spring brakes will hold you at a safe speed automatically

6.A tour bus has lost main air, and you need to reposition it using the separate air tank that serves its dual parking control valves. What limitation should shape how you plan the move?

Each push of the release button wears out the spring brakes permanentlyThe separate tank holds only enough air to release the brakes a few timesThe release button only works while the engine runs at a fast idleThe low air warning shuts the engine off after about one minute

7.You're applying for a passenger endorsement to drive a bus that has air brakes. Along with the knowledge test on Sections 2 and 4, what other knowledge test must you pass?

The combination vehicles test (Section 6)The doubles/triples test (Section 7)None; the passenger test already covers air brakesThe air brakes test (Section 5)

8.Why does the manual tell you to check brake adjustment often, rather than only at the pre-trip inspection?

Automatic slack adjusters only work during the first few miles of a tripAdjustment can change only when the air tanks are drainedBrakes can slip out of adjustment fast, particularly when they are hotEach time the governor cuts in, it loosens the slack adjusters

9.Halfway through a run, the yellow ABS malfunction lamp on your dash comes on and stays on. What does the manual advise?

You still have your regular brakes, so keep driving normally and get the ABS serviced soonPull over immediately, because the service brakes will no longer apply at allPump the brake pedal at every stop until the lamp goes back outSet the front brake limiting valve to 'slippery' to make up for the lost ABS

10.Before you check the slack adjusters on s-cam brakes during the walk-around, how should the truck be set up?

Parked on a slight incline with the parking brakes set so it can't rollEngine at a fast idle with the service brake pedal held downParking brakes applied and the air tanks drained to zeroParked on level ground with the wheels chocked and the parking brakes released