Rhode Island CDL — Air Brakes Practice Test 2

1.Your air compressor is driven by a belt. During the engine compartment part of your inspection, what does the manual have you check on that belt?

Only that it is the brand the maker installedIts condition and how tight it isIts color, which shows whether it is overheatingNothing, because compressor belts are checked only by a mechanic

2.A pre-trip check shows that brakes with automatic slack adjusters are out of adjustment. Apart from an emergency, what does the manual recommend?

Adjust them by hand and keep driving as usualIgnore it, since automatic adjusters will correct themselvesHave the vehicle taken to a repair shop promptly so the problem gets correctedBack the adjusters off so the brakes run cooler

3.A straight truck's air system is fully charged. You shut off the engine, push in the parking brake knob and time the gauge. Pressure drops 2.5 psi in one minute. How does that compare with the manual's limit?

It is fine, since a single vehicle may lose up to 3 psi a minute this wayIt is too much; a single vehicle should lose less than 2 psi in a minute with the brakes releasedIt is fine, since only combination vehicles are timedIt is too much only if the truck has ABS

4.In the manual Rhode Island tests from, a visible low air warning is required to switch on before tank pressure drops under what level?

45 psi60 psi100 psi125 psi

5.Only your tractor has ABS. As you brake, you see in the mirror that the trailer is starting to swing out. What does the manual tell you to do?

Brake harder so the tractor's ABS can straighten the trailerPull the parking brake knobSwitch to stab braking at full pressureEase off the brakes when it is safe

6.You are using controlled braking in an emergency and realize you need to steer more than a little to avoid a hazard. What should you do with the brakes?

Press harder so the vehicle slows before you turnPull the parking brake knob to help slow downRelease them, make the steering correction, then reapply as soon as you canKeep the same pressure and turn sharply

7.During the governor check, the compressor does not cut in and out at about the pressures the manufacturer specifies. Why does the manual treat this as something to fix?

The governor sets how hard the brakes apply, so braking would be unevenA faulty governor makes the ABS malfunction lamp stay onIt matters only on vehicles built before 1975A faulty governor might not hold enough air in the system to drive safely

8.Before the applied-brake leakage test, you build air up to governor cutoff. What range does the manual give for that cutoff pressure?

60 to 85 psi85 to 100 psi120 to 140 psi150 to 175 psi

9.On a dual air system, which tank's reading must still be at least 60 psi at the moment the low air warning comes on?

The tank with the highest pressureOnly the primary system's tankThe tank with the lowest pressureOnly the first tank the compressor fills

10.On a bus with dual parking control valves, how do the two controls differ?

One is a push-pull valve for setting the spring brakes to park; the other rests in the out position and, when pushed in, uses air from a separate tank to release themBoth are push-pull valves that do the same job, one serving as a backupOne works the front brakes and the other works the rear brakesOne fills the main air tanks and the other drains them