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Practice test 4 of 10

Alabama CDL — Air Brakes Practice Test 4

The Alabama CDL — Air Brakes knowledge test has ~25 questions; you need ~20 correct (80%) to pass.

This practice test follows that format: 25 questions, pass with 20 correct. Answer every page, then grade it to see the answers and explanations.

Questions 1–10 of 25

  1. 1.In an s-cam drum brake, what happens when air enters the brake chamber?
  2. 2.How does an air-operated disc brake differ from an s-cam brake?
  3. 3.Which type of foundation brake is the most common on vehicles with air brakes?
  4. 4.On a dual air system, the low air warning should come on before pressure drops below 55 psi in which system?
  5. 5.With the engine off and a fully charged system, what is the maximum acceptable air loss rate for a single vehicle?
  6. 6.When is it best NOT to set the parking brakes?
  7. 7.If the air compressor has its own separate oil supply, what should the driver do before a trip?
  8. 8.On a tractor or straight truck, spring brakes will come fully on when air pressure drops into roughly what range?
  9. 9.How are the powerful springs in spring brakes normally held back while you drive?
  10. 10.What is the purpose of an alcohol evaporator in an air brake system?

0 of 25 answered