Oklahoma CDL — Air Brakes Practice Test 8

1.The total stopping distance for an air brake vehicle is made up of which four parts?

Perception, reaction, brake lag, and braking distancePerception, reaction, cut-in, and cut-out distanceSteering, skid, drift, and braking distanceWarning, buzzer, spring, and braking distance

2.After you have selected the correct low gear for a long downgrade, how should you use the service brakes?

Ride the pedal with light steady pressure for the whole descentLeave them alone entirely and let the engine do all the slowingSqueeze hard enough to feel a clear drop in speed, then let off once you are roughly five mph under your safe speedTap the pedal quickly several times a minute no matter what your speed is

3.In a dual air brake system, what happens to stopping ability if one of the two systems is very low on pressure?

Braking becomes stronger on all axlesThe parking brakes release on their ownEither the front or rear brakes won't work fully, so stopping takes longerThe compressor shuts down permanently

4.How is the 'controlled braking' method performed during an emergency stop?

Pump the pedal quickly while turning the wheel sharplyPress the brakes fully and hold them until the vehicle stopsUse only the parking brake control to slow downBrake as hard as possible without letting the wheels lock

5.At about what tank pressure does the governor reach its cut-out point and stop the compressor from pumping?

Around 125 psiAround 55 psiAround 85 psiAround 150 psi

6.With the foot brake fully applied and held, what is the largest acceptable one-minute pressure drop for a combination vehicle?

Two psiThree psiFour psiTen psi

7.In a dual air system with the engine at operating rpm, air pressure should build within which range and time?

From 50 to 90 psi within three minutesFrom 85 to 100 psi within 45 secondsFrom 20 to 45 psi within ten secondsFrom 100 to 125 psi within five minutes

8.How does a 'wig wag' low-pressure warning device alert the driver?

It sounds a continuous horn from the engine bayIt flashes the headlights on and offIt drops a mechanical arm down into the driver's viewIt locks the steering wheel until pressure returns

9.How should you test that the parking brake will actually hold the vehicle?

Rev the engine to governor cutout with the brake releasedSet the parking brake and gently pull against it in a low gearDrive at five mph and then release the parking brakeDrain one air tank and watch the supply gauge

10.What does 'brake lag' refer to in an air brake system?

The delay before the brakes act after the pedal is pushedThe time needed to drain the air tanksThe gap between the cut-in and cut-out pressuresThe wait for the compressor to cool after a long drive