Ohio CDL — Air Brakes Practice Test

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

Or take one of 10 full-length practice tests

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

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The full-length test, with feedback and an explanation after every answer.

Ohio 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
What is the "controlled braking" method for an emergency stop?
Test 2
25 questions · pass with 20
The safety relief valve fitted to the first air tank is normally set to release pressure at what point?
Test 3
25 questions · pass with 20
On a truck whose air tanks have manually operated drain valves, how often should you drain them?
Test 4
25 questions · pass with 20
What does the manual say about manually adjusting an automatic slack adjuster just to bring it within limits?
Test 5
25 questions · pass with 20
Why does the manual warn against pressing the brake pedal while the spring brakes are already applied?
Test 6
25 questions · pass with 20
Before checking the slack adjusters by hand, what should you do first?
Test 7
25 questions · pass with 20
When you pull hard on an s-cam slack adjuster, about how much free movement suggests it needs adjustment?
Test 8
25 questions · pass with 20
How does a "wig wag" low-air warning device let the driver know pressure is low?
Test 9
25 questions · pass with 20
Air-brake truck tractors built on or after which date are required to have antilock brakes?
Test 10
25 questions · pass with 20
What is the main benefit that antilock brakes (ABS) provide?