CDL SUBSECTIONS 5.2 AND 5.3 EXAM QUESTIONS

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CDL SUBSECTIONS 5.2 AND 5.3 EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -6 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: How can you check that the spring brakes come on automatically?

Answer:

Fan off the air pressure by stepping on and off the brake pedal to reduce tank pressure. The tractor protection valve and parking brake should close (pop out) on a tractor-trailer combination vehicle and the parking brake valve should close (pop out) on the other combination and single vehicle types when the air pressure falls to the manufacturer's specifications (20-45 psi). This will cause the spring brakes to come on.

Question 2: What are maximum leakage rates?

Answer:

With a fully-charged air system (typically 125 psi). Turn off the engine, release the parking brake, and time the air pressure drop. The loss rate should be less then 2 psi in 1 minute for single vehicles and less than 3 psi in 1 minute for combination vehicles. Then apply 90 psi or more with the brake pedal.After the initial pressure drop, if the air pressure fails more then 3 psi in 1 minute for single vehicles.(More then 4 psi for combination vehicles)

Question 3: How can you check slack adjusters?

Answer:

Check Slack adjusters on S-Cam brakes. Park on level ground and chock the wheels to prevent the vehicle from moving. Release the parking brake so you can move the slack adjusters. Use gloves and pull hard on each slack adjuster that you can reach. If the slack adjuster moves more then about 1 inch where the push rod attaches to it, it probably needs adjustment. Adjust it or have it adjusted. Vehicles

with to much brake slack can be very hard to stop.

Question 4: What is a duel air brake system?

Answer:

A duel brake system has 2 separate air brake systems, which use a single set of brake controls. Each system has its own air tanks, hoses, lines, etc. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle (and possibly one rear axle) Both systems supply air to the trailer (if there is one). The first system is called the "primary" system. The other is called the "Secondary" system.

Question 5: What are the slack adjusters?

Answer:

The slack adjuster is the part of an air brake system that is used to just the brakes when needed. The slack adjuster is located on the air canister on the axle housing near the wheel. On vehicles with drum brakes, it is between the pushrods and the S-cam

Question 6: 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 then 60 psi in the air tank (or tank with the lowest air pressure, in dual air systems)