Air Brakes

1.

1 point

A slack udjuster's free play need to be adjusted if it is move than about how many inches when you pull hard on it?

1/4 Inch

1/2 inch

1inch

2.

1 point

The brake pedal in an air brake system:

is connected to slack adjusters by a series of rods and linkages.

controls the speed of the air compressor

controls the air pressure applied to put on the brakes

3.

1 point

Some air brake systems have an alcohol evaporator. What may happen if you don't keep the proper level of alcohol?

Ice may form on the brake drums and wear them out.

Ice may form in the air storage tank and cause brake failure

The S-Cam may not take back when you release the brake pedal

4.

1 point

If you must make anstop, you should brake so you:

can steer and your vehicle stays in a straight line

use the hand brake before the brake pedal

use the full power of the brakes to lock them

5.

1 point

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

To hold your speed when going down hill.

Any time when the vehicle is parked.

as little as possible.

6.

1 point

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

If you are going to use the parking brakes you need to make sure that they will hold the vehicle.

To brake vehicle very hard, in other words when coming down the steep grade.

To use parking brakes if you park for less than 1 hour

7.

1 point

An air brake system is fully charged at what psi?

100

125

75

50

8.

1 point

The braking power of the spring brakes:

Is not affected by the condition of the service brakes

increases when the service brakes are hot.

depends on the service brakes being in adjustment

9.

1 point

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

only during pre- and post-trip inspections

as little as possible

whenever you leave the vehicle unattended

10.

1 point

Repeatedly partially releasing and pressing the brake pedal may result in:

A loss of brake air pressure

no change of brake air pressure

a build up of brake air pressure

11.

1 point

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

60 psi

80 psi

40 psi

12.

1 point

If air pressure is not built up within the correct amount of time, then:

You should be ready to use your parking brakes to stop.

The alcohol container may be low.

Your air pressure may drop to a low point while driving, requiring an emergency stop.

13.

1 point

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

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

stay parked twice as long without using up service air pressure

balance the service brake system when you are parked.

14.

1 point

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

4 psi in one minute

1 psi in 30 seconds

2 psi in 45 seconds

15.

1 point

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

Only on slippery roads

Only when parked on a downhill

Never

16.

1 point

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

once a week

After every four hours of service

at the end of each day of driving

17.

1 point

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?

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

Reduce your speed, and test the remaining system while under way

Bring your vehicle to a complete stop right away and safely park. Continue only after the system is fixed.

18.

1 point

When brakes are applied the brake shoes will press against the:

Slack adjuster

Brake drum or disc

S-Cam

19.

1 point

The safety valve discharges automatically at the pressure of:

200

100

50

150

20.

1 point

Emergency Stab braking is:

Use light steady pressure on the brake pedal

When you press hard on the brake pedal and apply hand valve while you stop

Press on the brake pedal as hard as you can, release the brakes when the wheels locked, put on the brakes again when the wheels start rolling.

21.

1 point

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

Check and fill the alcohol level

check the oil for alcohol content

change the alcohol from a new bottle

22.

1 point

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

Spring Pressure

Air Pressure

Hydraulic pressure

23.

1 point

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

let the air out of air brake system

turn off the engine

be sure air brakes system is fully pressurized

24.

1 point

Why drain water from compressed air tanks?

Water low boiling point reduces braking power.

Water cools the compressor too much.

Water can freeze in cold weather and cause brake failure.

25.

1 point

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

Park on a slight grade, drain off air pressure, set parking brake and check to the movement.

Park on level ground, wait until normal air pressure is reached, release the parking brake and move forward.

Park on level ground, chock the wheels, engage the parking brakes when you have the correct amount of air

26.

1 point

All air brake equipped vehicles have:

a supply pressure gauge.

an air usage gauge

a back up hydraulic system

27.

1 point

The air compressor governor controls:

when air is pumped into the air tanks

Air pressure applied to the brakes

The speed of the air compressor.

28.

1 point

A combination tractor trailer air brake system should not leak at the rate of more than (blank) psi per minute with the engine off and the brakes released.

2

1

4

3

29.

1 point

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

Disc

S-cam drum

Wedge drum

30.

1 point

The air brake lag distance at 55 mph on dry pavement adds about

32 feet

52 feet

12 feet

31.

1 point

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

Spring Pressure

Air Pressure

bolts or clamps

32.

1 point

Your truck has dual air system and one of the systems loses its pressure. What will happen?

Brake drums will not be fully pressurized

The manual slack adjusters of the S-cam brakes will not be set properly.

Either the front or back brake will not be fully operational.

33.

1 point

The safety valve is set automatically when pressure is:

150

50

100

34.

1 point

It is accepted that too much heat caused by using your brakes too often can also cause:

brake linings to split up.

brakes to fade or fail.

modulating control valve to wear out

35.

1 point

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

Level ground, chock the wheels and release the parking brakes

Level grounds and drain off air pressure before checking the adjustment

Level ground and apply the parking brakes, then apply service brakes

36.

1 point

Your brakes are fading when:

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

less pressure is needed on the brake pedal for each stop

the brake pedal feel spongy when you apply pressure

37.

1 point

Modern air brake systems combine three different systems. They are the service, the parking, and the

Emergency brakes

Drum brakes

Disc brakes

Foot brakes

38.

1 point

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

Air Pressure

Spring Pressure

Fluid Pressure

39.

1 point

The air compressor stops pumping air at what psi?

125

150

100

40.

1 point

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

Proper adjustment of S-cam

Expansion of the brake drums and brake fading

Increase contact between the brake drums and linings

41.

1 point

Air braking takes more time than hydraulic braking because air:

Air brakes use different brake drums.

brakes require heavier return springs

Takes more time to flow through the lines than hydraulic fluid

42.

1 point

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

Emergency brake system

parking brake system.

service brake system

43.

1 point

The application pressure gauge shows how much air pressure you have:

have in the air tanks

are applying to the brakes

have in a modulating control valve

44.

1 point

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

upshift

stop and safely park as soon as possible.

downshift

45.

1 point

The S-Cam:

forces the brake shoes against the inside of the brake drum

Controls the flow of air to each of the brake chambers

pulls the brake shoes away from the drum and allow the wheels to roll freely

46.

1 point

The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below

100 psi

20 psi

60 psi