Arkansas CDL — Air Brakes Practice Test 7

1.Besides hiding the real fault, why does the manual call it dangerous to hand-adjust an automatic slack adjuster?

It cancels your CDL air brake endorsementIt disconnects the ABSIt can give you a false sense of security about how well the brakes workIt makes the compressor run nonstop

2.Water and compressor oil in an air brake system tend to settle in one part of each air tank. Where, and why does that matter?

At the top of the tank, where the safety valve lets them outAt the bottom of the tank, where each tank's drain valve is locatedIn the brake chambers at the wheels, where the slack adjusters push them outIn the governor, which filters them out on its own

3.According to the manual, which defect turns up most often during roadside inspections?

Brakes that are out of adjustmentAir tanks that have not been drainedA burned-out ABS lampA loose compressor belt

4.When does an antilock braking system actually step in?

Every time you press the brake pedalOnly when the wheels are about to lock upOnly at speeds above 55 mphOnly when the low air warning is on

5.Before troubleshooting a brake adjustment problem on automatic slack adjusters, what should you check first?

The ABS certification labelThat adjuster maker's own service manual, because different brands work differentlyThe governor's cut-out settingA general chart that applies to every brand of adjuster

6.On the CDL vehicle inspection test, what is the air brake check designed to confirm?

That the compressor can build pressure to 150 psiThat the air brake safety devices work properly as pressure falls from normal to low airThat the vehicle can stop from 55 mph within 450 feetThat the ABS lamp comes on at start-up

7.During the walk-around, which brake lining condition is acceptable?

Firmly attached, free of oil and grease, and not worn thinLoose on the shoeSoaked with greaseWorn dangerously thin

8.Your brakes are wet after a long run through heavy spray. How does the manual suggest drying them?

Set the parking brake hard and let it sit for an hourDrain the air tanks completelyDrive in a low gear and apply the brakes gently to heat themDrive at highway speed without braking

9.Your truck's brake system is designed so that pressing the pedal while the spring brakes are on will not hurt anything. What does the manual still advise?

Make a habit of not pressing the pedal while the spring brakes are on anywayYou may press the pedal freely, since the design protects the brakesPress the pedal firmly whenever the spring brakes are on to test the protectionOnly avoid it when the truck is loaded

10.Which statement about the application pressure gauge is true?

It shows how much air is in the tanks and is required on every air-braked vehicleIt shows how much air pressure you are putting to the brakes, and not every vehicle has oneIt shows the governor's cut-in and cut-out settingsIt lights up only when the spring brakes are applied