CDL Air Brakes | Study Guide ( Updated 2024 ) Complete Questions & Answers (Solved) 100% Correct
- Oil and water usually collect in compresed air tanks. If you do not have an automatic tank
drain, when should you drain the air tanks?Answer After every working day
- Why drain water from the compressed air tanks?
Answer: Water can freeze in cold weather and cause brake failure.
- The air brake system for a straight truck or bus should not leak at a rate of more than psi
per minute with the engine off and the brakes released.
Answer: 2
- To make an emergency stop with air brakes, using the stab braking method, you should:
Answer: Press on the brake pedal as hard as you can, release the brakes when the wheels locked, put on the brakes again when the wheels start rolling.
5. You should know that your brakes are fading when:
Answer: You have to apply the brake pedal harder to control speed on a downgrade.
- If the air compressor should develop a leak, what keeps the air in the tanks?
Answer: The one way check valve.
7. To check the brake slack on S-cam brakes you should park on:
Answer: Park on level ground, chock the wheels, and release the parking brakes.
8. The application pressure gauge shows how much pressure you have:
Answer: When you are applying to the brakes.
- The spring brakes used on the chambers in a straight truck will bring you to a stop when air
pressure drops below psi.
Answer: 20
- The safety valve is set to automatically reduce pressure at psi.
Answer: 150
- Your truck has a dual air system and one system loses its pressure. What will happen?
Answer: Either the front or back brake will not be fully operational.
- If your truck or bus has dual parking control valves, you can use pressure from a separate
tank to:
Answer: Release the spring emergency/parking brakes to move a short distance.
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- If your truck has a properly functioning dual air brake system and minimum size air tanks.
The air pressure should build from 85 to 100 psi within seconds?
Answer: 45
14. During normal driving, spring brakes are usually held back by:
Answer: Air pressure
- The air compressor stops pumping air at what psi?
Answer: 125
- The driver must be able to see a warning before pressure in the service air tanks falls below
psi.
Answer: 55
- Excessive use of the service brakes results in overheating which can lead to:
Answer: Expansion of the brake drums.
18. The most common type of foundation brake found on heavy vehicles is the:
Answer: S-cam drum
19. If you must make an emergency stop, brake so you:
Answer: Can steer and your vehicle stays in a straight line.
20. The braking power of the spring brakes:
Answer: Depends on the service brakes being in adjustment.
- The air brake lag distance at 55 mph on dry pavement adds about feet.
Answer: 32
- Total stopping distance for air brakes is longer than that for hydraulic brakes due to
distance.
Answer: Brake lag
- It is accepted that too much heat caused by using your brakes too often can also cause:
Answer: Brake fade or failure
24. Repeatedly pressing and releasing (fanning) the brake pedal may result in:
Answer: The loss of brake air pressure
- The brake system that applies and releases the brakes when the driver uses the brake pedal
is the brake system.
Answer: Service
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