FREE AND STUDY GAMES ABOUT AB CDL EXAM

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FREE AND STUDY GAMES ABOUT AB CDL EXAM

QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -75 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: Why is it called an "S-cam"?

Answer:

It is shaped like the letter "S" Question 2: The S-cam:

Answer:

Forces the brake shoes against the inside of the brake drum

Question 3: Which of the following can cause brakes to fade or fail?

Answer:

All of the above.

Question 4: When you press the brake pedal,

Answer:

Compressed air enters the brake chambers

Question 5: Which of the following is NOT part of the drum brake?

Answer:

Safety Valve Question 6: Your vehicle has a dual air brake system. One of the systems loses air pressure.What will happen?

Answer:

Either the front or rear brakes will not be fully operational.Question 7: During normal driving, spring brakes are usually held back by:

Answer:

Air pressure Question 8: An antilock braking system (ABS):

Answer:

Activates when your wheels are about to lock up Question 9: A typical air brake system is fully charged at:

Answer:

125 psi Question 10: On large, heavy vehicles, the parking brake or emergency brakes must be held on

by something that cannot leak away, such as:

Answer:

Spring pressure Question 11: On a long or steep downgrade, once you have reached your "safe" speed, brake

until you are traveling:

Answer:

• mph slower

Question 12: What is the best way to test of your vehicle's spring brakes come on automatically?

Answer:

All are correct

Question 13: The stop light switch:

Answer:

Turns on the brake lights when you brake

Question 14: How would you check your truck's slack adjusters?

Answer:

Use gloves and pull hard on each slack adjuster you can reach Question 15: Spring brakes are:

Answer:

Brakes that come on automatically on a truck or tractor when the psi drops too low, not going to take full effect until your psi drops to a certain range (20-30 psi), made up of powerful springs that are held back by air pressure while you are driving Question 16: The air compressor governor controls:

Answer:

When air is pumped into the air storage tanks Question 17: Under ideal conditions, the average driver of a truck or bus equipped with air brakes and traveling at 55 mph would require what stopping distance?

Answer:

More than 400 feet Question 18: The purpose of a supply pressure gauge is:

Answer:

To tell you how much air is in the tank Question 19: The driver must be able to see a low pressure warning, which comes on before

pressure in the service air tank falls below:

Answer:

60 psi

Question 20: Which of the following is NOT part of the air brake system?

Answer:

Radio signal system

Question 21: With S-cam drum brakes, when the brake chamber fills with air, air pressure pushes the push rod out, moving the ____ and thus rotating the _____.

Answer:

Slack adjusters, brake camshaft Question 22: In a vehicle equipped with air brakes, the brake pedal:

Answer:

Controls the air pressure applied to the service brakes

Question 23: What is the supply pressure gauge used for?

Answer:

To show how much pressure is in the air tanks Question 24: The low air pressure warning signal will come on before the pressure in the air

tanks falls below:

Answer:

55 psi Question 25: The tractor protection valve:

Answer:

Provides the air supply for the brake system, will close if you apply the parking brakes, will close automatically if the air supply drops to a certain level Question 26: To test the air service brakes:

Answer:

Brake firmly while slowly moving forward Question 27: The parking brake control:

Answer:

Let's the air out of the brake chambers Question 28: Slack adjusters are:

Answer:

Between the push rod and S-cam on drum brakes, part of the air brake system that is used to adjust the brakes, and between the power screw and push rod on disc brakes