New Mexico CDL — Air Brakes Practice Test 6

1.Which order matches the manual's hand check of slack adjusters on s-cam brakes?

Chock the wheels, set the parking brakes, pull on each slack adjuster, then move to level groundPark on level ground, chock the wheels, release the parking brakes, then pull hard on each slack adjuster you can reachRelease the parking brakes, pull on each slack adjuster, then chock the wheels and parkPark on level ground, set the parking brakes firmly, pull on every slack adjuster within reach, then chock the wheels

2.Section 5 of New Mexico's manual has the low air pressure warning come on before tank pressure falls below 60 psi. Which figure does the air brake check in Section 11, the vehicle inspection test, use for the same warning?

60 psi, the same as Section 5, with no manufacturer alternative55 psi, or the level the manufacturer specifies45 psi, or one half of governor cut-in80 to 85 psi on every vehicle

3.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

4.Several figures in Section 5 carry a reminder to check the manufacturer's specifications. Which of these does the section state as a fixed limit, with no such reminder?

The governor's cut-in and cut-out pressuresThe air leakage allowed in one minuteThe pressure at which the spring brake valves pop outThe buildup time on a vehicle with larger than minimum air tanks

5.New Mexico's list of CDL restrictions has two entries about air brakes, L and Z. Which of them is printed with a note on how the restriction is removed?

Only LOnly ZBoth L and ZNeither one

6.On the vehicle inspection test, how much play at the center of the air compressor belt does Section 11 count as snug?

1/8 to 1/4 inch1 to 1 1/2 inches1/2 to 3/4 inchNone; a snug belt should not deflect at all

7.The first component of Section 11's air brake check has you shut off the engine before you release the brakes and hold the foot brake down. Where does the manual say to leave the key?

In the "off" position, taken out of the switchIn the "start" position, held against the springIn the "accessory" position, with the headlights onIn the "on" or "battery charge" position

8.Section 5 lists the checks that make up the Step 7 final air brake check. Which one does it list first?

The rate of air pressure buildup at operating rpmThe parking brakeThe low pressure warning signalThe governor's cut-in and cut-out pressures

9.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

10.Section 5 tells you to use a low or lower gear in several situations. Which of these is NOT one of them?

Testing whether the parking brake will holdRolling forward for the five-mph service brake testDrying very wet brakes before parking in freezing weatherResponding to brakes that are starting to fade