Alabama CDL Air Brakes Practice Test (AL) 2

5 out of 5 (39 votes)
80% Passing score
20 Questions
4 Mistakes allowed
If you're gearing up for your CDL in Alabama, getting your air brakes endorsement is a crucial step. Our Alabama CDL air brakes practice test is designed to prepare you thoroughly for this. With 20 multiple-choice questions, this test covers essential topics such as components, operation, safety inspections, and stopping distance calculations. You'll learn about dual air brake systems, which are critical for safety, providing a backup if one system fails. To pass, you need to correctly answer at least 16 questions. One of the highlights of our Alabama CDL air brakes practice test is the review feature. After completing the test, you can review your answers and see explanations for any questions you missed. This helps you understand the material better and ensures you're fully prepared for the actual DMV permit test. The format mirrors the real test, using multiple-choice and true-or-false questions, helping you practice the process of eliminating incorrect answers to find the right one. The questions are based on the official Alabama driver's manual, the same source used for the actual DMV permit test. This ensures that you're studying the most accurate and relevant information. If it's not in the manual, it won't be on the test. Driving in Alabama comes with unique challenges, from navigating rural roads to understanding the impact of local weather conditions like heavy rains and occasional ice. This Alabama CDL air brakes practice test takes these local factors into account, making sure you're not just prepared for the test, but also for driving in Alabama. Our Alabama DMV air brake test is more than just a study tool; it's your comprehensive guide to mastering the air brakes section of the CDL test. Dive in, test your knowledge, and ensure you're ready to hit the road safely and confidently in Alabama.
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Sample Alabama Air Brakes Test Questions

Question 1

On an older air-brake vehicle with a driver-controlled front-brake limiting valve, the control should normally remain in the “normal” position, even on slippery roads. True or false?

  1. A True
  2. B False

Correct answer: A – True

The Alabama manual teaches that front-wheel braking is effective under all conditions and that braking-related front-wheel skids are unlikely even on ice. Placing a limiting-valve control in the “slippery” position cuts front-brake pressure and reduces stopping power. Keep the driver-controlled valve in “normal” for normal braking performance.

Source: Alabama Commercial Driver License Manual — § 5.1.13, “Front Brake Limiting Valve”

Question 2

What is the main reason for draining an air-brake vehicle’s storage tanks?

  1. A To complete the exterior inspection
  2. B To measure service-brake adjustment
  3. C To remove collected water and compressor oil
  4. D To trigger the low-air warning device

Correct answer: C – To remove collected water and compressor oil

Compressed air normally contains some moisture and compressor oil. These contaminants collect in the bottoms of the storage tanks and can interfere with proper brake-system operation. Manual drains should be opened as directed to empty the tanks completely; automatic drains should also be checked to ensure they are working.

Source: Alabama Commercial Driver License Manual — § 5.1.4, “Air Tank Drains”

Question 3

Which method should be used to control speed on a long, steep downgrade?

  1. A Wait until speed is 5 mph above the safe speed, then brake back to the safe speed
  2. B Use only the trailer brakes throughout the descent
  3. C Use repeated emergency or stab braking
  4. D Use a proper low gear and engine braking; at the safe speed, brake to about 5 mph below it, then release

Correct answer: D – Use a proper low gear and engine braking; at the safe speed, brake to about 5 mph below it, then release

Select the proper low gear before beginning the downgrade and use engine braking as the principal means of controlling speed. When the vehicle reaches its safe speed, apply the brakes firmly enough to produce a definite slowdown. Release them at approximately 5 mph below the safe speed and repeat as necessary.

Source: Alabama Commercial Driver License Manual — § 2.16.4, “Proper Braking Technique”

Question 4

Which condition is a major cause of brake fade?

  1. A Rain cooling the brake drums
  2. B Excessive use of the service brakes
  3. C Moving slowly through congested traffic
  4. D Applying the parking brake after stopping

Correct answer: B – Excessive use of the service brakes

Repeated or prolonged service-brake use creates excessive heat and can cause the brakes to fade or fail. The Alabama manual explains that overheating changes the brake lining and expands the drums, reducing braking force. Using engine braking on downgrades helps preserve the service brakes for slowing or stopping when needed.

Source: Alabama Commercial Driver License Manual — § 5.4.5, “Brake Fading or Failure”

Question 5

What cold-weather hazard can be caused by water collecting in compressed-air tanks?

  1. A It can cool the compressor below operating temperature
  2. B It can cause the brake drums to expand
  3. C It can freeze and prevent the brakes from operating properly
  4. D It can increase the compressor oil level

Correct answer: C – It can freeze and prevent the brakes from operating properly

Moisture carried in compressed air can collect in the storage tanks. During cold weather, that water may freeze within the air-brake system and interfere with airflow or brake operation. Draining the tanks removes this moisture, along with collected compressor oil, before it can create a braking problem.

Source: Alabama Commercial Driver License Manual — § 5.1.4, “Air Tank Drains”

Question 6

The effectiveness of spring-operated emergency and parking brakes depends primarily on what condition?

  1. A The brakes being hot
  2. B The foundation brakes being properly adjusted
  3. C The brakes being tested only by a repair technician
  4. D The condition of the service brakes having no effect

Correct answer: B – The foundation brakes being properly adjusted

Spring brakes apply mechanical force to the foundation brakes, but they cannot work correctly when those brakes are out of adjustment. Poor adjustment reduces both regular service-brake performance and emergency or parking-brake effectiveness. Brake adjustment must be inspected and maintained rather than relying only on the strength of the springs.

Source: Alabama Commercial Driver License Manual — § 5.1.14, “Spring Brakes”

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