Arkansas CDL — Air Brakes Practice Test 2

11.Where is the safety relief valve installed in an air brake system?

On each brake chamber at the wheelsOn the dash, next to the parking brake knobIn the first tank that the compressor pumps air intoOn the last tank before the trailer air lines

12.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

13.Which vehicles does the manual say must have emergency brakes and parking brakes held on by mechanical force?

Only vehicles built after 1998Only vehicles that haul hazardous materialsOnly combination vehiclesAll trucks, truck tractors, and buses

14.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

15.With the controlled braking method, how hard do you press the brakes?

All the way down, releasing only after the wheels lockFirmly, but short of the point where the wheels lockJust hard enough to feel a slowdown, for about three secondsLightly, letting the engine do all the stopping

16.During the final air brake check, your governor fails to cut the compressor in and out as it should. Why does that matter?

It only affects how loud the compressor runsIt causes the ABS lamp to stay onIt makes the safety valve open at 55 psiIt may fail to hold enough air pressure to drive safely

17.What is the job of the air compressor governor?

It limits how fast the truck can go on air brakesIt releases air if tank pressure gets too highIt warns you when air pressure is lowIt controls when the compressor pumps air into the storage tanks

18.You must brake hard to avoid a stalled car, and your truck's ABS is working. What should ABS let you do that locked wheels would not?

Steer around the obstacle while you are brakingAlways stop in half the usual distanceTake your foot off the brake and let ABS stop the truckBrake without watching your mirrors

19.For the 'no air brake equipped CMV' (L) restriction, which braking systems count as air brakes?

Any system that works fully or partly on the air brake principleOnly systems that work entirely on airOnly systems with spring brakesOnly systems on vehicles built after 1975

20.Partway through a trip, your air compressor quits. What can you still count on from the air already stored in the tanks?

Normal braking for the rest of the trip, since the tanks refill themselvesEnough air to use the brakes several timesNothing at all, because the brakes fail the moment the compressor stopsEnough air to keep the spring brakes released for as long as you need