SECTION 5 - AIR BRAKES EXAM QUESTIONS

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SECTION 5 - AIR BRAKES EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -19 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: Front wheel brakes are good under all conditions. True or False?

Answer:

True. Front wheel braking is good under all conditions. Tests have shown front wheel skids from braking are not likely even on ice.

Question 2: How can you test the low pressure warning signal?

Answer:

Shut the engine off when you have enough air pressure so that the low pressure warning signal is not on. Turn the electrical power on and step on and off the brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 60 psi in the air tank (or tank with the lowest air pressure, in dual air systems).

Question 3: You still have normal brake functions if your

ABS is not working. True or False?

Answer:

True. Without ABS, you still have normal brake functions. Drive and brake as you always have.

Question 4: The use of brakes on a long, steep downgrade is only a supplement to the braking effect of the engine. True or False?

Answer:

True. The use of brakes on a long and/or steep downgrade is only a supplement to the braking effect of the engine.

Question 5: How should you brake when you drive a

tractor-trailer combination with ABS?

Answer:

When you drive a tractor-trailer combination with ABS, you should brake as you always have. In other

words:

Use only the braking force necessary to stop safely and stay in control.Brake the same way, regardless of whether you have ABS on the tractor, the trailer, or both.

Question 6: Why must air tanks be drained?

Answer:

Compressed air usually has some water and some compressor oil in it, which is bad for the air brake system.

Question 7: What are spring brakes?

Answer:

Spring brakes are usually used as emergency brakes and parking brakes for all trucks, truck tractors, and buses. When driving, powerful springs are held back by air pressure. If the air pressure is removed, the springs put on the brakes.

Question 8: How often should you drain air tanks?

Answer:

You must drain the tanks yourself at the end of each day of driving.

Question 9: Why should you be in the proper gear before starting down a hill?

Answer:

To provide engine braking effect while in low gear on a down grade.Question 10: If you are away from your vehicle only a short time, you do not need to use the parking brake. True or False?

Answer:

False. Any time you park, use the parking brakes, except if the brakes are very hot (from just having come down a steep grade), or if the brakes are very wet in freezing temperatures.

Question 11: What is a supply pressure gauge used for?

Answer:

This gauge shows how much air pressure you are applying to the brakes. (This gauge is not on all vehicles.)

Question 12: All vehicles with air brakes must have a

low air pressure warning signal. True or False?

Answer:

True. A low air pressure warning signal is required on vehicles with air brakes.

Question 13: What are the slack adjusters?

Answer:

Slack Adjusters are on S-cam Brakes. If a slack adjuster moves more than about one inch where the push rod attaches to it, it probably needs adjustment.

Question 14: What is a dual air brake system?

Answer:

A dual air brake system has two separate air brake systems, which use a single set of brake controls.Each system has its own air tanks, hoses, lines, etc.

Question 15: How can you check that the spring brakes come on automatically?

Answer:

Continue to fan off the air pressure by stepping on and off the brake pedal to reduce tank pressure. The tractor protection valve and parking brake valve should close (pop out) on a tractor-trailer combination vehicle and the parking brake valve should close (pop out) on other combination and single vehicle types when the air pressure falls to the manufacturer's specification (20 - 45 psi).

Question 16: How do you know if your vehicle is equipped with antilock brakes?

Answer:

Vehicles with ABS have yellow malfunction lamps to tell you if something isn't working.

Question 17: What factors can cause brakes to fade or fail?

Answer:

Excessive use of the service brakes results in overheating and leads to brake fade. Brake fade results from excessive heat causing chemical changes in the brake lining, which reduce friction, and also causing expansion of the brake drums.

Question 18: How can you check slack adjusters?

Answer:

Release the parking brakes so you can move the slack adjusters. Use gloves and pull hard on each slack adjuster that you can reach. If a slack adjuster moves more than about one inch where the push rod attaches to it, it probably needs adjustment.

Question 19: What are the maximum leakage rates?

Answer:

With a fully-charged air system (typically 125 psi), turn off the engine, release the parking brake (push in); and time the air pressure drop. The loss rate should be less than two psi in one minute for single vehicles and less than three psi in one minute for combination vehicles.