Missouri's air brake exam has how many questions?
The Missouri air brake exam has 25 questions, and 80 percent is needed to pass.
Missouri · MOChange state
Free Missouri (MO) CDL Air Brakes practice test 2026
The section applicants fail most often. Pressure figures differ by state manual.
What’s different in Missouri
Most Air Brakes questions are the same federal material in every state. 2 questions in the app are written for Missouri alone, from the Missouri Commercial Driver License Manual (Version 4.0, Revised August 2025).
- Skills test version: The modernized skills test.Missouri's CDL manual and licensing pages
Two Missouri questions, answer shown
What does Missouri's L restriction also prohibit, beyond full air brakes?
L bars air brakes, and Missouri specifies that L drivers also may not operate air-over-hydraulic systems. Remove it by passing the air brake written test and a skills test in an air-braked vehicle.
A sample question
One example, answer shown. Practicing the rest happens in the app.
At approximately what pressure does the air compressor governor stop pumping air into the tanks?
The governor 'cut-out' pressure is about 125 psi. When tank pressure falls to roughly 100 psi, the governor cuts back in and the compressor resumes pumping.