CDL Air Brakes Test #3 | Free Practice Questions & Answers

Air Brakes Test #3
(english)

Air Brakes Test #3 (en)

1 / 24

The modulating control valve lets you control:

Spring brakes.

Rear wheel speed

Tire pressure balance

2 / 24

What is true about the antilock braking system?

ABS makes your tires last longer.

ABS changes the way you brakes in emergencies.

ABS improves fuel efficiency.

3 / 24

What does the brake pedal do in an air brake system?

Sends signals to the vehicle's lights and indicators.

Controls the air pressure applied to put on the brakes.

Adjusts the vehicle's steering direction.

4 / 24

Before you drive a truck or bus that has a dual air brake system, the air pressure needs to be at least ______ psi.

100

120

5 / 24

The service line has a big leak, so you hit the brakes. Service air pressure will escape, causing _____.

Engine to overheat

Brakes to release automatically.

Trailer emergency brakes to come on.

6 / 24

Emergency controlled braking is when you _______.

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

Press down on the accelerator while lightly tapping the brakes.

Turn off the engine and coast to a stop.

7 / 24

When is it NOT a good time to use the parking brakes?

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

When you're waiting at a long traffic light.

When driving through a tunnel.

8 / 24

When testing combination vehicles with the engine off and brakes applied, the air pressure should not drop more than ____ psi every minute.

9 / 24

Whenever you park, always use the parking brakes, except:

If the brakes are very hot (e.g., after just coming down a steep grade).

If the parking area is completely level.

If the parking spot is designated for short-term parking only.

10 / 24

How many extra feet does it take for an air brake to start working when you're going 55 mph on a dry road?

11 / 24

Air brakes consists of three different braking systems: service, parking and ______.

Emergency

Hydraulic

Disc

12 / 24

It's not safe to drive a vehicle if its brake drums have cracks bigger than ______ of the friction area.

1/2

1/4

1/8

13 / 24

What should you do if your truck or bus has dual air brakes and a warning light turns on because one system has low pressure?

Ignore the warning and focus on your driving.

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

Continue driving as normal and check the system after your trip.

14 / 24

What tells you how much air pressure is in the tanks?

Fuel meter

Water level indicator

Supply pressure gauge

15 / 24

How do you do emergency stab braking the right way?

Pump the brakes gently until the vehicle stops.

Apply your brakes all the way. Release the brakes when wheels lock up. As soon as the wheels start rolling, apply the brakes fully again.

Turn off the engine immediately.

16 / 24

What will happen if your truck has a dual air system and one loses air pressure?

The truck will automatically speed up.

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

The brake lights will remain on continuously.

17 / 24

When driving at 55 mph on a dry road, how many feet will air brake lag distance add to your total stopping distance?

18 / 24

When the engine is turned off and the brakes are not applied, the air brake system in a straight truck or bus shouldn't lose more than ______ psi every minute.

19 / 24

If your truck has a dual air brake system and one of them doesn't have enough pressure:

The vehicle will take longer to stop.

The brake pedal will feel unusually soft.

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

20 / 24

Some trucks have an alcohol evaporator. What may happen if you don't maintain the right level of alcohol in it?

The brakes may overheat and stop working properly.

Ice may form in the air brake valves and cause brake failure.

The brake fluid could evaporate, leading to total brake loss.

21 / 24

The brake pedal in an air brake system:

Controls the air pressure applied to the brakes.

Adjusts the temperature of the brake pads.

Increases the amount of fuel to the engine

22 / 24

At what psi is an air brake system considered to be fully charged?

100

125

23 / 24

The parking brake on a vehicle with air brakes should be used:

To stop at traffic lights.

Whenever you leave the vehicle unattended.

When you're driving at a high speed.

24 / 24

When the straight truck engine is off and the brakes are on, the air loss rate should not exceed ______ .

3 psi in one minute.

4 psi in 2 minutes

5 psi in 3 minutes

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Air Brakes Test #1 (english)

Air Brakes Test #2 (english)

Air Brakes Test #4 (english)

What is the CDL Air Brakes Test?

The CDL Air Brakes test is a written exam that covers the principles of air brake operation, inspection, and maintenance. The test is designed to ensure that drivers understand how air brakes work and how to operate them safely. This test is required for any driver who wants to operate a commercial vehicle equipped with air brakes. This page provides resources and information to help you prepare and pass the exam.

Who Needs to Take the CDL Air Brakes Test?

Anyone who wants to drive a commercial vehicle with air brakes is required to take and pass this test. This includes drivers who want to operate:

Tractor-trailers
Buses
Trucks with a GVWR of 26,001 pounds or more

Why are Practice Tests Important?

Practicing for the CDL Air Brakes test is crucial for success. Here’s why:

Familiarization: Practice tests help you become familiar with the format of the real exam, the types of questions you’ll encounter, and the time constraints.
Knowledge Assessment: They allow you to assess your current knowledge and identify areas where you need to focus your studies.
Confidence Building: Taking practice tests and seeing your progress can boost your confidence and reduce test anxiety.
Improved Performance: Studies have shown that students who use practice tests perform significantly better on exams.