New Mexico CDL — Air Brakes: Safe Driving Practices Practice Test

Question 1

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?

Accepted Answer

55 psi, or the level the manufacturer specifies — The two sections do not print the same number. Section 5 uses 60 psi, while the Section 11 air brake check has the buzzer, light or flag activate before pressure is below 55 psi or the manufacturer's specified level.

Answer

60 psi, the same as Section 5, with no manufacturer alternative

Answer

45 psi, or one half of governor cut-in

Answer

80 to 85 psi on every vehicle

Question 2

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

Accepted Answer

The governor's cut-in and cut-out pressures — The list opens with the governor check and then goes on to the air leakage rate, the low pressure warning signal, the automatic application of the spring brakes, the buildup rate, the parking brake and finally the service brakes.

Answer

The rate of air pressure buildup at operating rpm

Answer

The parking brake

Answer

The low pressure warning signal

Question 3

You have just finished inspecting the brake components at one axle on the vehicle inspection test. What does the note in Section 11 tell you to be ready for?

Accepted Answer

The same brake inspection at every axle, power unit and trailer alike — The note that follows the brake items tells you to be prepared to carry out the same inspection of brake components at each axle, covering the power unit and, if the vehicle has one, the trailer.

Answer

Skipping the remaining axles once the first one has checked out

Answer

Repeating the inspection on the steering axle and nowhere else

Answer

Repeating the inspection only if the examiner points out a defect

Question 4

On the vehicle inspection test you check the brake chambers at an axle. Which of these is NOT one of the things Section 11 has you look for?

Accepted Answer

That each chamber is labeled with its pushrod stroke limit — Section 11's brake chamber item covers leaks, cracks and dents, secure mounting, and clamps that are loose or missing. It says nothing about stroke-limit labels on the chambers.

Answer

That the chambers are not leaking

Answer

That the chambers are not cracked or dented

Answer

That they are mounted securely, with no loose or missing clamps

Question 5

The Step 7 check times air leakage twice, once with the brakes released and once with the foot brake held down. What do the two tests have in common?

Accepted Answer

The engine is off and the parking brake is released — Both tests start from a charged system with the engine shut off and the parking brake released. The difference is the foot brake: left alone in the first test, held fully applied for one minute in the second.

Answer

The engine runs at a fast idle and the parking brake is set

Answer

The electrical power is off and the air tanks have been drained

Answer

The vehicle is rolling forward at about five mph

Question 6

You are assigned a truck built in 1990. Based on the manual's statement about automatic slack adjusters, what can you assume about this truck?

Accepted Answer

Nothing for certain; the manual's statement covers vehicles built since 1994 — The manual's statement is that automatic slack adjusters are on every vehicle built since 1994, which leaves an older truck outside it. Either way the adjusters get checked, because the manual says even automatic ones must be.

Answer

It must have automatic slack adjusters, as every air-braked vehicle on the road does

Answer

It cannot have slack adjusters of any kind

Answer

It has automatic slack adjusters that never need to be checked

Question 7

The service brake check on the vehicle inspection test has you pull forward at 5 mph and stop. Which kind of service brakes does Section 11 say it covers?

Accepted Answer

Air or hydraulic service brakes — Section 11 applies the check to service brakes of either kind, air or hydraulic. Its purpose is to confirm the brakes do their job and that the vehicle stops without pulling left or right.

Answer

Air service brakes only

Answer

Hydraulic service brakes only

Answer

Spring brakes only

Question 8

Does the manual give air-braked vehicles a separate inspection routine of their own?

Accepted Answer

No; the Section 2 seven-step inspection is used, with air brake items added — Section 5 tells you to follow the seven-step procedure from Section 2. An air-braked vehicle simply has more to inspect, and the extra items are presented in the order in which they fall within those seven steps.

Answer

Yes; a separate five-step air brake routine replaces the seven-step inspection

Answer

Yes; air-braked vehicles are to be inspected by a mechanic only

Answer

No; air brakes need no checks beyond those for hydraulic brakes

Question 9

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

Accepted Answer

Park on level ground, chock the wheels, release the parking brakes, then pull hard on each slack adjuster you can reach — The wheels are chocked first because the parking brakes then have to be released so the slack adjusters can move. Only after that do you put on gloves and pull each one you can reach, looking for more than about one inch of travel.

Answer

Chock the wheels, set the parking brakes, pull on each slack adjuster, then move to level ground

Answer

Release the parking brakes, pull on each slack adjuster, then chock the wheels and park

Answer

Park on level ground, set the parking brakes firmly, pull on every slack adjuster within reach, then chock the wheels

Question 10

A driver who studied another state's manual tests the low pressure warning on a late-model New Mexico truck. Pumping the brake pedal with the engine off, he sees the warning first come on at 57 psi and calls it a pass. How does that compare with Section 5 of New Mexico's manual?

Accepted Answer

It falls short; the signal must come on before pressure drops below 60 psi — In Section 5's Step 7 test, the warning signal has to come on before pressure in the tank, or in the lowest tank of a dual system, drops under 60 psi. A warning that waits until 57 psi is late by that standard.

Answer

It passes; the signal only has to come on somewhere before pressure reaches 55 psi

Answer

It passes; any signal that comes on above 45 psi meets the manual's standard

Answer

It falls short; the signal must already be on by the time pressure reaches 85 psi

Question 11

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

Accepted Answer

Rolling forward for the five-mph service brake test — A low gear is named for the parking brake test and for drying wet brakes, and a lower gear is the remedy when rising application pressure shows the brakes are fading. The service brake test only says to move forward slowly and brake firmly.

Answer

Testing whether the parking brake will hold

Answer

Drying very wet brakes before parking in freezing weather

Answer

Responding to brakes that are starting to fade

Question 12

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?

Accepted Answer

The air leakage allowed in one minute — The governor pressures, the spring brake pop-out pressure and the longer buildup time for larger tanks all point you to the manufacturer. The leakage limits are stated outright: 2 and 3 psi with the brakes released, 3 and 4 psi with them applied.

Answer

The governor's cut-in and cut-out pressures

Answer

The pressure at which the spring brake valves pop out

Answer

The buildup time on a vehicle with larger than minimum air tanks

New Mexico CDL — Air Brakes: Safe Driving Practices practice test

Study questions with answers

1. 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?

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

3. You have just finished inspecting the brake components at one axle on the vehicle inspection test. What does the note in Section 11 tell you to be ready for?

4. On the vehicle inspection test you check the brake chambers at an axle. Which of these is NOT one of the things Section 11 has you look for?

5. The Step 7 check times air leakage twice, once with the brakes released and once with the foot brake held down. What do the two tests have in common?

6. You are assigned a truck built in 1990. Based on the manual's statement about automatic slack adjusters, what can you assume about this truck?

7. The service brake check on the vehicle inspection test has you pull forward at 5 mph and stop. Which kind of service brakes does Section 11 say it covers?

8. Does the manual give air-braked vehicles a separate inspection routine of their own?

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

10. A driver who studied another state's manual tests the low pressure warning on a late-model New Mexico truck. Pumping the brake pedal with the engine off, he sees the warning first come on at 57 psi and calls it a pass. How does that compare with Section 5 of New Mexico's manual?

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

12. 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?

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