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Free California (CA) CDL Air Brakes practice test 2026

The section applicants fail most often. Pressure figures differ by state manual.

What’s different in California

Most Air Brakes questions are the same federal material in every state. 10 questions in the app are written for California alone, from the California Commercial Driver Handbook (DL 650).

  • Low air warning in the pre-trip inspection (skills test): Before pressure drops below 55 psi.California's CDL manual and licensing pages
  • Skills test version: Both versions, depending on the test site.California's CDL manual and licensing pages
  • California rule: Static leakage test limits are 2 psi for single vehicles, 3 psi for a combination of two, and 5 psi for a combination of three or more.California manual, section 5.3.3
  • California rule: Static leakage test allows 5 psi for a combination of three or more vehicles.California manual, section 5.3.3
  • California rule: The maximum air loss rate for a combination of two or more vehicles is 2 psi if the towed vehicles are not equipped with air brakes.California manual, section 5.3.3

Two California questions, answer shown

In California's static leakage test, how much air may a single vehicle lose in one minute?

  1. No more than 2 psi
  2. No more than 3 psi
  3. No more than 4 psi
  4. No more than 6 psi

With the system charged, the engine off and all brakes released, a single vehicle may lose no more than 2 psi over one minute. More than that means a leak to repair before driving.

Handbook section 5.3.3

According to the California handbook, vehicles built since which year all have automatic slack adjusters?

  1. 1975
  2. 1998
  3. 1994
  4. 1991

California puts the changeover at 1994. Automatic adjusters still need checking, because one that is out of adjustment signals a fault rather than a missed adjustment.

Handbook section 5.3.2
8 more California-only Air Brakes questions in the app

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?

  1. 125 psi
  2. 150 psi
  3. 100 psi
  4. 60 psi

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.

Handbook section 5.1.2
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More for California

General KnowledgeCombination VehiclesPre-Trip InspectionHazardous MaterialsDoubles & TriplesTank VehiclesPassenger TransportSchool Bus