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CDL EXAM > CDL Air Brakes Test > Flashcards

CDL Air Brakes Test Flashcards

1
Q

Air brakes use

A. hot air
B. cold air
C. compressed air
D. decompressed air

A

C. compressed air

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2
Q

Air brake systems are three braking systems combined. They are

A. emergency, service, hand.
B. emergency, parking, service.
C. parking, service, hand.
D. None of the above

A

B. emergency, parking, service.

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3
Q

Which of the following pumps air into the air storage tanks?

A. Safety valve
B. Air compressor
C. Governor
D. Reservoir

A

B. Air compressor

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4
Q

The main purpose of the alcohol evaporator is to

A. put alcohol in gas tanks
B. remove alcohol from the compressor
C. remove alcohol form the storage tank
D. put the alcohol in the air system

A

D. put the alcohol in the air sysem

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5
Q

A safety relief valve is installed in the first tank the air compressor pumps air to. The valve is usually set to open at what psi level?

A. 130
B. 140
C. 150
D. 160

A

C. 150

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6
Q

The most common foundation brake is the

A. wedge brake
B. S-cam drum brake
C. disc brake
D. front brake

A

B. S-cam drum brake

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7
Q

The brake system that applies and releases the brakes when the driver uses the brake pedal is the ____ brake system.

A. emergency
B. service
C. parking
D. trailer

A

B. service

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8
Q

The low air-pressure warning light must come on before the air pressure in the tanks falls below what psi level?

A. 30
B. 40
C. 50
D. 60

A

D. 60

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9
Q

Spring brakes do which of the following?

A. They use air pressure to stop the vehicle
B. They will not work if all the air leaks out of the air brake system
C. They are held by mechanical force
D. They will come on fully at 50 psi

A

C. They are held by mechanical force

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10
Q

Which of the following tells you how much pressure there is in the air tanks?

A. Stop-light switch
B. Application pressure gauge
C. Supply pressure gauge
D. Low-air-pressure warning signal

A

C. Supply pressure gauge

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11
Q

Why, on long downhill grades, do experts recommend using a low gear and light steady pressure instead of on-again, off-again braking?

A. Air usage is less with lightly steady pressure
B. Brake linings do not heat up as much
C. You can keep vehicle speed constant in a low gear with light steady pressure
D. All of the above

A

D. All of the above

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12
Q

The braking power of spring brakes depend on

A. proper adjustment
B. how far the modulating control lever (if present) is moved
C. traction
D. All of the above

A

D. All of the above

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13
Q

Most newer heavy-duty vehicles use dual air brake systems for safety. A dual air brake system has

A. two seperate air brake systems and two sets of brake controls
B. two seperate air brake systems and a single set of brake controls
C. one air brake system and two sets of brake control
D. one air brake system and one brake control

A

B. two seperate air brake systems and a single set of brake controls

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14
Q

Foundation brakes are used

A. only in emergencies
B. when parking
C. at each wheel
D. at each axle

A

C. at each wheel

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15
Q

During walkaround inspections of your vehicle, which parts of the air brake system shoud be checked?

A. Manual slack adjusters on S-cam brakes
B. Brake drums or discs
C. Air hoses connected to brake chambers
D. All of the above

A

D. All of the above

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16
Q

During the walkaround inspection, if a slack adjuster moves slightly more than an inch where the push rod attaches to it, then

A. it has the perfect amount of slack
B. it probably needs adjustment
C. the brakes will stop the vehicle very suddenly
D. it will pass roadside inspection

A

B. it probably needs adjustment

17
Q

You have a fully-charged air system (125 psi). Ater turning off the engine and releasing the service brake, what are the maximum leakage reates per minute for both single and combination vehicles?

A. 2 psi for single, 3 psi for combination
B. 3 psi for both
C. 4 psi for both
D. 4 psi for single, 5 psi for combination

A

A. 2 psi for single, 3 psi for combination

18
Q

In checking that the spring brakes come on automatically, you should not

A. pull the parking brake control knob
B. chock the wheels
C. step on and off the brake pedal
D. shut the engine off

A

A. pull the parking brake control knob

19
Q

Which of the following is a proper technique in using controlled braking?

A. Putting the brakes on very hard to lock the wheels
B. Releasing the brakes if you need to make large steering adjustments
C. Pressing harder on the brakes when you feel the wheels sliding
D. Turning the steering wheel while braking

A

B. Releasing the brakes if you need to make large steering adjustments

20
Q

Total stopping distance for air brakes is longer than that for hydraulic brakes due to ____ distance.

A. perceptive
B. reaction
C. brake lag
D. None of the above

A

C. brake lag

21
Q

You are driving a vehicle at 55 mph on dry pavement under good traction and brake conditions. What is the approximate total stopping distance needed to bring your vehicle to a complete stop?

A. Two-and-a-half-times the length of the vehicle
B. Half the length of a football field
C. Just over the lenghth of a football field
D. The length of the vehicle plus 20 feet

A

C. Just over the length of a football field

22
Q

What should you do if the low-air-pressure warning comes on?

A. Use stab braking until you stop
B. Drive to the nearest rest area
C. Nothing; the vehicle will stop automatically
D. Stop your vehicle as quickly as possible and safely park it

A

D. Stop your vehicle as quickly as possible and safely park it

23
Q

If your truck or bus has dual parking control valves, you can use pressure from a seperate tank to:

A. balance the service brake system when you are parked
B. release the spring emergency/parking brakes to move a short distance
C. brake harder if the main tank is getting low
D. keep on about your business

A

B. release the spring emergency/parking brakes to move a short distance

24
Q

When braking on downgrades,

A. go slow enough so that a light, steady use of the brakes keeps you from speeding up
B. brake hard, then let up to cool brakes
C. coast downhill, then apply the brakes hard
D. use stab braking until wheels lock, then release

A

A. go slow enough so that a light, steady use of brakes keeps you from speeding up

25
Q

How often should you drain your air tanks?

A. Once a week
B. At the end of each workday
C. Twice a week
D. Biweekly

A

B. At the end of each workday

26
Q

Which of the following statements is true?

A. If you are gone only a short time, you do not need to use the parking brakes or chock the wheels
B. Never leave your vehicle unattended without applying the parking brakes or chocking the wheels
C. It is nto necessary to use the parking brake or chock your wheels if you are parked on a flat road surface
D. If you park right after coming down a very steep grade, you should always use the parking brake

A

B. Never leave your vehicle unattended without applying the parking brakes or chocking the wheels

27
Q

When should you NOT use the parking brakes?

A. If the brakes are very hot
B. If the brakes are wet during freezing weather
C. When testing the spring brakes
D. All of the above

A

D. All of the above

28
Q

What protects the tank and the rest of the air system from too much pressure?

A. Safety valve
B. Foot valve
C. Treadle valve
D. Draining valve

A

A. Safety valve

29
Q

Before driving a vehicle with a dual air system, allow time for the air compressor to build up to 100 psi pressure in which of the following?

A. The primary sysem only
B. The secondary sysem only
C. Both the primary and secondary systems
D. It only has to build to 60 psi pressure in each sysem

A

C. Both the primary and secondary systems

30
Q

Pressing and releasing the brake pedal quickly and repeatedly

A. will stop your vehicle faster
B. will help cool your brakes
C. can let the air out faster than the compressor can replace it
D. pumps air back into the air brake

A

C. can let the air out faster than the compressor can replace it

CDL EXAM (3 decks)

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