Missouri CDL — Air Brakes Practice Test

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

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25 questions · pass with 20 correct. You get instant feedback and an explanation after every answer.

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Missouri CDL — Air Brakes practice tests

10 full-length practice tests, each with 25 questions and a pass mark of 20, like the real test. You see the answers and explanations after you grade.

Test 1
25 questions · pass with 20
Why should you avoid pressing the foot brake while the spring brakes are already applied?
Test 2
25 questions · pass with 20
Why do air brakes have 'brake lag' that hydraulic brakes do not?
Test 3
25 questions · pass with 20
In an s-cam brake, what does the s-cam do when the brakes are applied?
Test 4
25 questions · pass with 20
In the recommended downgrade braking pattern, once your speed is about 5 mph below your safe speed, what do you do?
Test 5
25 questions · pass with 20
At roughly what tank pressure does the governor tell the compressor to stop pumping (cut-out)?
Test 6
25 questions · pass with 20
What do air brakes depend on to operate the brakes?
Test 7
25 questions · pass with 20
On newer vehicles, how do you set the parking (spring) brakes?
Test 8
25 questions · pass with 20
What is a 'wig wag' device?
Test 9
25 questions · pass with 20
At roughly what tank pressure does the governor tell the compressor to stop pumping (cut-out)?
Test 10
25 questions · pass with 20
What best describes a dual air brake system?