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CDL > 에어 브레이크 > Flashcards

에어 브레이크 Flashcards

1
Q

How should you check that your service brakes are working properly?

A. Park on level ground, chock the wheels, engage the parking brake when you have the correct amount of pressure.

B. Park on level ground, wait for normal air pressure, release the parking brake, move the truck forward slowly (about 5mph) and apply the brakes firmly using the brake pedal.

A

B.

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2
Q

Excessive heat caused by using your brakes too often can cause the:

A. Brakes to fade or fail.

B. Modulating control valve to wear out.

A

Brakes to fade or fail.

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3
Q

The most common type of foundation brakes found on heavy vehicles is the:

A. Disc brake

B. S-cam drum

A

S-cam drum

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4
Q

Air braking takes more time than hydraulic braking because:

A. Air takes more time to flow through the lines than hydraulic fluid.

B. Air brakes use different brake drums.

A

Air takes more time to flow through the lines than hydraulic fluid.

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5
Q

Of the choices below, the first thing to do when a low air pressure warning comes on is:

A. Open the air supply control valve.

B. Stop and safely park as soon as possible.

A

Stop and safely park as soon as possible.

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6
Q

Why should you drain water from compressed air tanks?

A. Water cools the compressor too much.

B. Water can freeze in cold weather and cause brake failure.

A

Water can freeze in cold weather and cause brake failure.

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7
Q

If your vehicle has an alcohol evaporator, it is there to:

A. Reduce the risk of ice in air brake valves in cold weather.

B. Eliminate the need for daily tank draining.

A

Reduce the risk of ice in air brake valves in cold weather.

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8
Q

You should know that your brakes are fading when:

A. You have to push harder on the brake pedal to control your speed on a downgrade.

B. The brake pedal feels spongy when pressure is applied.

A

You have to push harder on the brake pedal to control your speed on a downgrade.

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9
Q

The air compressor governor controls:

A. Air pressure applied to the brakes.

B. When air is pumped into the air tanks.

A

When air is pumped into the air tanks.

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10
Q

Under normal conditions in order to engage the parking brakes, the driver must first:

A. Be sure that the air brake system is fully pressurized.

B. Let the air out of the air brake system.

A

Let the air out of the air brake system.

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11
Q

Some air brake systems have an alcohol evaporator. What may happen if you don’t keep the unit filled with alcohol?

A. Ice may form in the air storage tanks and cause the brakes to fail.

B. Ice may form on the brake drums and warp them.

A

Ice may form in the air storage tanks and cause the brakes to fail.

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12
Q

Your system has a dual air brake system. If a low air pressure warning comes on for the secondary system, you should:

A. Bring the vehicle to a safe stop and continue only when the system is fixed.

B. Reduce your speed and drive to the nearest garage for repairs.

A

Bring the vehicle to a safe stop and continue only when the system is fixed.

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13
Q

If the spring brakes on, when should you push the brake pedal?

A. Never

B. Only when driving downhill.

A

Never

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14
Q

A straight truck or bus air brake system should not leak at a rate of more than:

A. 2 psi/min with the engine off and the brakes are released.

B. 3 psi/min

A

2 psi/min with the engine off and the brakes are released.

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15
Q

During normal driving, spring brakes are usually held back by:

A. Spring pressure.

B. air pressure.

A

air pressure

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16
Q

It is not safe to drive a vehicle that has brake drums, or discs with cracks that are longer than:

A. 1/4 of the width of the friction area

B. half (1/2) the width of the friction area.

A

half (1/2) the width of the friction area.

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17
Q

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

A. brake lag distance

B. Effective braking distance.

A

brake lag distance

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18
Q

The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:

A. 1 psi/ min

B. 3 psi /min

A

3 psi / min

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19
Q

The air brake lag distance at 55 mph on a drive pavement adds about:

A. 32 feet to your stopping distance

B. 52 feet

A

32 feet to your stopping distance

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20
Q

If your vehicle has an alcohol evaporator, every day during cold weather you should:

A. check and fill the alcohol level

B. Check the oil for alcohol content.

A

check and fill the alcohol level

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21
Q

The application pressure gauge shows how much air pressure you :

A. Have in the air tanks.

B. are applying to the brakes

A

are applying to the brakes

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22
Q

When is it ok to leave your truck unattended without applying the parking brake or chocking the wheels?

A. If you are conducting a pre-trip inspection.

B. never

A

never

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23
Q

The use of air brakes on a long and/or steep downgrade under normal conditions is only a supplement to:

A. The braking effect of the engine.

B. The use of the spring brakes.

A

The braking effect of the engine.

24
Q

If air pressure does not build up to normal within the correct amount of time, then:

A. Your air pressure may drop too low during driving requiring an emergency stop.

B. You should be read to use your parking brakes to help stop.

A

Your air pressure may drop too low during driving requiring an emergency stop.

25
Q

Which of these is not a proper time to apply the parking brakes?

A. If you will only be stopped for less than 1 hour.

B. If the brakes are very hot, for example, after just coming down a steep grade.

A

If the brakes are very hot, for example, after just coming down a steep grade.

26
Q

A supply pressure gauge tells you how much air is in the:

A. air tank

B. Tractor brake lines.

A

Air tank

27
Q

Excessive use of the service brakes results in overheating, which can lead to:

A. Improper adjustment of the S-cam.

B. expansion of the brake drums.

A

expansion of the brake drums.

28
Q

The proper method of braking when going down and/or steep grades after selecting the proper gear is to brake until your speed is about:

A. 10 mph below your safe speed.

B. 5 mph below your safe speed, then release your brakes.

A

5 mph below your safe speed, then release your brakes.

29
Q

To check the free play of manual slack adjusters on S-cam brakes, you should park on:

A. Level ground, chock the wheels and turn off the parking brake

B. Level ground with the parking brake, then apply the service brake.

A

Level ground, chock the wheels and turn off the parking brake

30
Q

Emergency stab braking is when you:

A. Press hard on the brake pedal and apply full hand valve until you stop.

B. Brake as hard as you can, release the brakes when the wheels lock, put on the brakes again when the wheels start rolling.

A

Brake as hard as you can, release the brakes when the wheels lock, put on the brakes again when the wheels start rolling.

31
Q

If your truck has a properly functioning dual air brake system and minimum size air tanks, the air pressure should build from 85 to 100 psi within:

A. 45 seconds.

B. 30 seconds.

A

45 seconds

32
Q

Repeatedly pressing and releasing (fanning) the brake pedal may result in:

A. A build up of brake air pressure

B. A loss of brake air pressure

A

A loss of brake air pressure

33
Q

When the brakes are applied, the brake shoes or linings are pressed against the:

A. S-cam

B. brake drum or disc.

A

brake drum or disc.

34
Q

The brake pedal in an air brake system:

A. controls the speed of the air compressor.

B. Controls the air pressure applied to put on the brakes.

A

Controls the air pressure applied to put on the brakes.

35
Q

With air brake vehicles, the parking brakes should be used:

A. Whenever you leave the vehicle unattended.

B. As little as possible.

A

Whenever you leave the vehicle unattended.

36
Q

If your truck’s air compressor has its own oil supply, when should you first check the oil level?

A. before driving.

B. During your first en route inspection.

A

Before driving

37
Q

Under ideal conditions, a truck with air brakes going 55 mph would require a stopping distance of:

A. 100- 300 feet

B. More than 300 feet.

A

More than 300 feet

38
Q

Parking or emergency brakes of trucks and buses can be legally held on by:

A. spring pressure

B. air pressure

A

spring pressure

39
Q

The most important thing to do when a low air pressure warning comes on is:

A. downshift

B. Stop and safely park as soon as possible.

A

Stop and safely park as soon as possible.

40
Q

Why drain water from compressed air tanks?

A. Water can freeze in cold weather and cause brake failure.

B. The low boiling point of water reduces braking power.

A

Water can freeze in cold weather and cause brake failure.

41
Q

The supply pressure gauge show how much pressure:

A. is in the air tanks.

B. is going to the brake chamber.

A

is in the air tanks.

42
Q

If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage air tanks?

A. After every 4 hours of service.

B. at the end of each day of driving

A

at the end of each day of driving

43
Q

Your truck or bus has a dual air brake system, if a low air pressure warning comes on for only one system, what should you do?

A. Stop right away and safely park; continue only after the system is fixed.

B. Reduce your speed.

A

Stop right away and safely park; continue only after the system is fixed.

44
Q

To test air service brakes, you should:

A. Brake firmly when slowly moving forwards.

B. Brake firmly when slowly moving backwards.

A

Brake firmly when slowly moving forwards.

45
Q

The modulating control valve allows you to control the:

A. Front brakes.

B. spring brakes

A

spring brakes

46
Q

If your truck has a dual air system and one of the system is low on pressure:

A. The brake drums will not be fully pressurized.

B. Either the front or rear brakes will not be fully operational.

A

Either the front or rear brakes will not be fully operational.

47
Q

The braking power of the spring brakes:

A. depends on the service brakes being in adjustment.

B. Is not affected by the condition of the service brakes.

A

depends on the service brakes being in adjustment.

48
Q

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

A. Apply more brake pressure if the main tank is getting low.

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

A

Release the spring emergency parking brakes to move a short distance.

49
Q

Emergency controlled braking is when you:

A. apply the brakes as hard as you can without locking the wheels.

B. Apply the hand valve for 1 sec, then push hard on the brake pedal.

A

apply the brakes as hard as you can without locking the wheels.

50
Q

The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away like:

A. air pressure.

B. spring pressure.

A

spring pressure.

51
Q

If you must make an emergency stop, brake so you:

A. can steer and your vehicle stays in a straight line.

B. can steer hard while brake hard.

A

can steer and your vehicle stays in a straight line.

52
Q

All air brake equipped vehicles have:

A. A supply pressure gauge

B. An air use gauge.

A

A supply pressure gauge

53
Q

A slack adjuster probably needs to be adjusted if it moves more than about:

A. 1/2 inch when you pull hard on it.

B. 1 inch when you pull hard on it.

A

1 inch when you pull hard on it.

54
Q

How should you check that the spring brakes come on when air pressure in the system drops below a certain level?

A. park on level ground, chock the wheels, release the parking brake when you have enough air pressure, shut the engine off and repeatedly press and release the brake pedal.

B. park on level ground, wait for the normal pressure.

A

park on level ground, chock the wheels, release the parking brake when you have enough air pressure, shut the engine off and repeatedly press and release the brake pedal.

55
Q

The S-cam:

A. Pulls the brake shoes away from the drum and allows the wheels to roll freely.

B. forces the brake shoes against the inside of the brake drum

A

forces the brake shoes against the inside of the brake drum

CDL (6 decks)

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