Utah CDL — Air Brakes Practice Test 7

11.Air-brake truck tractors must have antilock brakes if built on or after which date?

March 1, 1998January 1, 1994March 1, 1997March 1, 1975

12.During the final air-brake check, at about what pressures should the governor cut the compressor in and out?

Cut in near 55 psi and cut out near 80 psiCut in near 125 psi and cut out near 150 psiCut in near 20 psi and cut out near 45 psiCut in near 100 psi and cut out near 125 psi

13.An air brake setup actually combines how many separate braking systems into one?

Three - the service, parking, and emergency brakesOnly one combined braking circuitTwo - a service brake and a hydraulic backupFour - including a separate vacuum system

14.If your brakes are too hot to set the parking brakes safely, how should you secure the vehicle?

Set the parking brakes anywayKeep the service brake pedal pressed downChock the wheels on level ground and let the brakes coolRev the engine to keep pressure up

15.Why must emergency and parking brakes be held on by mechanical force?

Because springs cost less than air valvesBecause air can slowly leak off over timeBecause air brakes may not be used for parkingBecause mechanical force builds air pressure

16.What describes the 'controlled braking' method during an emergency?

Jamming the brakes down and holding themPumping the pedal quickly at randomBraking as hard as possible without locking the wheelsRelying on the parking brake alone

17.The safety relief valve on the first air tank starts letting air escape. What does that tell you?

The tanks have finished draining the way they shouldThe alcohol evaporator is due for a refillThe spring brakes are on the verge of applyingSomething has gone wrong and a mechanic needs to repair it

18.Only the trailer in your combination is equipped with antilock brakes. What should you expect while braking?

The trailer brakes will release themselves on downgradesYou have to brake far harder than usual to make up for the tractorA trailer swing-out is less likely, but ease off if steering fails or the tractor starts to foldThe tractor brakes shut down during any hard stop

19.Total stopping distance with air brakes is made up of how many separate factors?

TwoFourThreeFive

20.What color is the malfunction lamp that warns of an ABS problem?

RedGreenYellowBlue