New Mexico CDL — Air Brakes Practice Test 10

11.Which order matches the way the manual says an air-operated disc brake applies?

Air pressure reaches the brake chamber, the push rod drives a wedge, and the shoes spread against the discAir pressure turns the power screw, the screw moves the slack adjuster, and the s-cam clamps the discAir pressure reaches the brake chamber, the slack adjuster turns the power screw, and the caliper's pads clamp the discThe caliper's pads clamp the disc, the power screw turns, and air pressure is then let into the brake chamber

12.A bus has dual parking control valves. At the end of a run, which of the two does the manual assign to setting the spring brakes when you park?

The valve that is spring loaded in the "out" positionEither one; the two valves do the same jobThe push-pull valveNeither; the brake pedal sets the spring brakes on a bus

13.Your low air pressure warning comes on while you are driving. Which of these is NOT part of what the manual says about that situation?

You should stop and park safely as soon as you canAn air leak in the system is a possible causeControlled braking works only while enough air is left in the tanksPumping the brake pedal will bring the pressure back up

14.Your truck's air compressor is gear-driven, so there is no compressor belt to show the examiner on the vehicle inspection test. What does Section 11 require instead?

Nothing; a component that has no belt is left out of the engine compartment inspection altogetherTell the examiner it is not belt driven, then check that it works, is undamaged, is not leaking and is secureTake off the gear cover so that the examiner can see the compressor drive and judge its conditionRun the engine at a fast idle and time how quickly the air pressure builds to governor cutout

15.You brake hard on a slick road in a vehicle without ABS, and wheels other than the steering wheels lock up. Which of these is NOT one of the results the manual lists for that?

The vehicle skidsThe vehicle rolls overThe vehicle jackknifesThe vehicle spins

16.How many components does New Mexico's manual say make up the air brake check on the vehicle inspection test, and what follows if they are not all performed correctly?

Four components; points are deducted for each one missedTwo components; only the air brake check has to be repeatedThree components; the vehicle inspection test is failed automaticallySeven components; the examiner allows one retry on the spot

17.A mechanic is tracing why a truck's brake lights stay dark when the air brakes are applied, even though the bulbs are good. Which air brake part described in the manual is responsible for switching those lights on?

The low air pressure warning signalThe application pressure gaugeThe stop light switchThe air compressor governor

18.Section 11 limits how far a brake pushrod may move when you pull on it by hand. Which pairing of slack adjuster type and brake condition goes with its one-inch limit?

Automatic slack adjusters, with the brakes releasedManual slack adjusters, with the brakes appliedAutomatic slack adjusters, with the brakes appliedManual slack adjusters, with the brakes released

19.Whichever emergency braking method you choose, the manual wants your braking to accomplish two things. What are they?

Keep the vehicle in a straight line and still let you turn if you have toStop in the shortest distance possible, even with the wheels lockedLock the drive wheels while the steering wheel is held perfectly stillBring the spring brakes on a moment ahead of the service brakes

20.You are building pressure in a New Mexico truck with a dual air system. The low air warning light and buzzer shut off when both gauges reach 58 psi. How does that compare with Section 5 of New Mexico's manual?

It is too low; the manufacturer's shut-off value has to be greater than 60 psiIt is fine; the warning may shut off anywhere above 45 psiIt is fine; the warning should shut off once either system passes 55 psiIt is too low; the warning has to stay on until both systems reach governor cut-out