Kansas CDL — Air Brakes Practice Test 7

11.Besides slowing the truck, what does the friction inside a brake drum create, and why does it matter?

Extra air pressure, which helps refill the tanksMoisture, which collects in the brake chambersHeat, and too much of it can make the brakes quit workingStatic electricity, which can trip the ABS lamp

12.A driver estimates his air-braked truck's total stopping distance by adding perception distance, reaction distance, and braking distance. What has he left out?

Brake lag distanceFollowing distanceCoasting distanceEngine braking distance

13.Your trailer has ABS but your tractor does not. What does the trailer's ABS make less likely when you brake?

The trailer swinging outThe tractor jackknifingLosing steering control at the frontBrake lag

14.Your CDL carries the Z restriction, 'no full air brake equipped CMV.' Which of these may you still drive?

A CMV whose brakes run entirely on airAny air-braked CMV, as long as it has ABSA CMV with air-over-hydraulic brakesNo CMV with air brakes of any kind

15.Which sequence matches how the air brake check on the CDL vehicle inspection test is carried out?

Leakage rate test, governor cut-out check, emergency brake test, warning device testAir gauge and governor cut-out check, leakage rate test, warning device test, emergency brake testWarning device test, emergency brake test, governor cut-out check, leakage rate testEmergency brake test, leakage rate test, air gauge check, warning device test

16.On the CDL vehicle inspection test's air brake check, you shut off the engine before the leakage test. Where should the key be for the leakage and warning device tests?

In the 'on' or 'battery charge' position, without restarting the enginePulled out of the ignitionIn the 'start' position with the engine crankingOff, with the battery disconnected

17.You're about to pull an old trailer built before ABS was required, and you can't tell whether it was fitted with ABS. What does the manual suggest looking for underneath it?

A red air line running to the front of each brake chamberAn electronic control unit (ECU), plus wheel speed sensor wires running out of the rear of the brakesA second set of brake chambers mounted on every axleA blue diamond-shaped decal next to the trailer's air couplers

18.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

19.In an emergency stop, when does the manual say an ABS-equipped vehicle's brakes may be pushed all the way down?

Whenever the tractor has ABS, even if the trailer does notWhenever the pavement is dry and the vehicle is loadedWhen the straight truck or combination you drive always has working ABS on all of its axlesOnly once the ABS malfunction lamp has come on during the trip

20.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