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CDL > Air Brakes > Flashcards

Air Brakes Flashcards

1
Q

The stop light switch:

A

Turns on the brake lights to warn drivers behind you

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2
Q

Truck and bus parking or emergency brakes must be heald on by:

A

Mechanical Force

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3
Q

The most common type of fundation brake found on heavy vehicles is the:

A

S-cam drum

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4
Q

You are on a steep downgrade and have reached your “safe” speed of 40 mph. You would apply the service brake until you speed drops to ___

A

35 mph

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5
Q

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

A

Chock the wheels, release the parking brake, shut the engine off, and check for movement

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6
Q

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

A

Before Driving

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7
Q

For air brake systems, the air compressor should start pumping at no lower than ___psi

A

85 psi

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8
Q

You should know you brakes are fading when:

A

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

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9
Q

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

A

The loss of brake air pressure

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10
Q

The air brake lag distance at 55 mph on dry pavement adds about ___feet to you stopping distance

A

32 ft

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11
Q

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

A

Any time the vehicle is parked

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12
Q

If the spring bakes are on, when should ypou push the brake pedal?

A

Never

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13
Q

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

A

Either the front or rear brakes will not be fully operational

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14
Q

The air loss rate for a straight truck or bus with the engine off and the brakes on should no be more than:

A

3 psi in one minute

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15
Q

The brake pedal in an air brake system:

A

Controls the air pressure applied to put on the brakes

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16
Q

The braking power of the spring brakes:

A

Depends on the service brakes being in adjustment

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17
Q

The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below___psi.

A

55 psi

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18
Q

What is emergency control braking:

A

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

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19
Q

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

A

Release spring emergency/parking brakes to move a short distance

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20
Q

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

A

Air pressure

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21
Q

The parking or emergency brakes of trucks and buses can be legally heald on by ___ pressure

A

Spring

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22
Q

The air compressor governor controls:

A

When air is pumped into the air storage tanks

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23
Q

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

A

Air Tanks

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24
Q

When you apply the brakes, the brake shoes/linings are pressed against the:

A

Brake Drum

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25
Q

Why drain water from compressed air tanks?

A

Water can freeze in cold weather and cause brake failure

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26
Q

Some 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

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27
Q

The (first) most important thing to do when low air pressure warning comes on is:

A

Stop and safely park as soon as possible

28
Q

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

A

Check and fill the alcohol level

29
Q

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 ___ seconds

A

45 seconds

30
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 and safely park. Continue only after the system is fixed

31
Q

It is not safe to drive a vehicle that has brake drums (or discs) with craks or that are thinner than manufacturer’s specifications, generally this will be ___ inch.

A

1/4 inch

32
Q

Air braking takes more time than hydralic braking because air:

A

takes more time to flow through the lines than hydraulic fluid

33
Q

Total stopping distance for vehicles with brakes is longer than that for vehicles with hydralic brakes due to ___ distance

A

Brake Lag

34
Q

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

A

Can steer and you vehicle stays in a straight line

35
Q

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

A

Never

36
Q

The use of air brakes on a downgrade is only a supplement to the:

A

Braking effect on the engine

37
Q

The proper method of braking when going down long and/or steep grades after selecting the proper gear, is to brake until you speed is about ___ miles per hour below your “safe” speed, then release your brakes.

A

5 mph

38
Q

The S-cam:

A

Forces the brake shoes agaist the inside of the brake drum

39
Q

To test air service brakes, you should:

A

Brake firmly when slowly moving forwards

40
Q

If you dont have automatic tanks drains, how often should you drain the oil and water from the bottom of compressed air storage air tanks?

A

At the end of each day of driving

41
Q

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

A

When you brakes are very hot

42
Q

the brake system that applies and releases the brakes when the driver uses the brake pedal is the ___ brake system

A

Service

43
Q

For air brake systems in good condition, the air compressor should start pumping at about ___ psi.

A

100 psi

44
Q

Before driving a truck or bus with a dual brake system, the pressure in each system should be at least ____psi.

A

100 psi

45
Q

Modern air brake systems are three different systems combined together. They are the service, parking, and the ___ brakes.

A

Emergency

46
Q

The modulating control valve allows you to control the:

A

Spring Brakes

47
Q

Exessive heat in the brakes can cause the:

A

brakes to fade or fail

48
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 whe you have enough pressure, shut the engine off, and repeatedly press and release the brake pedal

49
Q

The applicatipn pressure gauge shows how much air pressure you:

A

Are applying to the brakes

50
Q

What is emergency stab braking?

A

brake hard, release the brakes when the wheels lock, and reapply the brakes when the wheels start rolling

51
Q

Under normal conditions, to engage the parking brake the driver must first:

A

Let the air out of the spring brakes

52
Q

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

A

Either the front or rear brakes will not be fully operational

53
Q

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

A

Spring Pressure

54
Q

The air supply pressure gauge shows how much pressure:

A

Is in the air tanks

55
Q

All air brake equipped vehicles have:

A

An air supply pressure gauge

56
Q

If air pressure does NOT build up fast enough within the correct amount of time:

A

Your air pressure may drop too low during driving

57
Q

The spring brakes used on tractors and straight trucks will bring you truck to a stop when air pressure drops below ___ psi

A

20 psi

58
Q

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

A

wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake firmly using the brake pedal

59
Q

To check the brake slack on S-cam brakes, you should park on:

A

level ground, chock the wheels, and release parking brakes

60
Q

The air brake system for a straight truck or bus should not leak at a rate of more than ___ psi per minute with the engine OFF and the brakes released.

A

2 psi/min

61
Q

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

A

3 psi in one minute

62
Q

The safety valve is set to automatically reduce pressure at ___ psi

A

150 psi

63
Q

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

A

Whenever you leave the vehicle unattended

64
Q

A truck with air brakes going 55 mph would require a stopping distance of:

A

More than 300 feet

65
Q

If you vehicle has an alcohol eveporator, it is there to:

A

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

66
Q

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

A

Service

67
Q

The air compressor governor controls:

A

When air is pumped into the air tanks

CDL (3 decks)

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