- Entry Level Driver Training Vehicle Systems and Malfunctions Questions and Answers Flashcards

What is the purpose of the one-way check valve in the air brake system?

Answer: To allow air to flow in only one direction, preventing backflow from the tanks to the compressor

The one-way check valve allows air to flow from the compressor into the air tanks but prevents it from flowing back, ensuring that pressure is maintained even if the compressor fails.

How does the spring brake (parking brake) system work on a CMV?

Answer: Powerful springs apply the brakes when air pressure is released from the brake chambers

Spring brakes use powerful coil springs inside the brake chambers that apply braking force when air pressure is released. Air pressure holds the springs compressed during normal operation.

What is the purpose of an alcohol evaporator in the air brake system?

Answer: To introduce alcohol into the air system to help prevent ice from forming in air lines

An alcohol evaporator automatically introduces a small amount of alcohol into the air system during cold weather to prevent moisture from freezing in the air lines and valves.

What are the warning signs of a failing alternator?

Answer: Dimming lights, warning light on dashboard, dead battery, and electrical system malfunctions

Signs of alternator failure include dimming or flickering headlights, the battery/charging warning light illuminating, a dead or low battery, and erratic electrical system behavior.

What should you do if your headlights suddenly fail while driving at night?

Answer: Immediately activate emergency flashers, turn signals, or any available lights and pull over safely

If headlights fail at night, immediately activate any available lights (flashers, turn signals, parking lights) to maintain visibility, slow down, and pull off the road as safely as possible.

What is the proper procedure for draining air tanks on a CMV?

Answer: Open the drain valve on each tank at the end of each day to release accumulated moisture

Air tanks should be drained at the end of each day of driving by opening the drain valve at the bottom of each tank, allowing accumulated water and oil to escape.