MD CDL Air Brakes study plan

Label each major air brake component (compressor, governor, reservoirs, foot valve, relay valve, spring brake chambers, slack adjusters) and state its function in one sentence

Trace the air path from compressor intake through the governor cut-out to the primary and secondary reservoirs on a hand-drawn diagram

Explain the difference between the service brake system and the parking/emergency spring brake system

Define cut-in and cut-out pressure and state the typical psi range for each

Describe how the compressor builds pressure and how the governor controls the cycle

Explain the purpose of the air dryer, safety valve, and drain valves, and when each matters

List the reservoir types (wet, primary, secondary) and what each supplies

Identify the causes and symptoms of air pressure loss or slow buildup

Describe the correct sequence for a normal brake application and a full release with the foot valve

Explain how application pressure relates to stopping distance and how to judge it by feel

Identify the low air pressure warning device, its trigger threshold, and the required driver response

Explain how the spring brakes apply automatically when pressure drops too low

Perform and narrate the pre-trip air brake inspection in the correct order

Demonstrate the static leak test: build to governor cut-out, shut off engine, and check pressure loss over one minute

Perform the applied-leak test with the foot valve held and record the drop

Test the low air pressure warning and spring brake pop-out at the specified thresholds

Check slack adjuster and pushrod travel against the legal limit

Explain the purpose and operation of the parking brake valve and the tractor protection valve

Describe how to test the parking brake for holding power on a grade

List the steps for an emergency stop if service brakes fail

Identify when to use the parking brake versus the emergency spring brakes

Explain how brake fade, overheating, and improper adjustment affect stopping distance

Describe safe downhill braking technique, including gear selection and controlled applications

Explain how load weight, road surface, and speed change required stopping distance

Identify common driver errors that cause air brake failures on the road

Run a full timed pre-trip inspection with no missed steps

Answer 50 mixed practice questions across all domains and log every wrong answer with the reason

Re-test the two weakest domains until scores reach 90%

Recite the low-pressure and emergency braking thresholds from memory

Complete two full-length timed practice exams under test conditions

Review every missed question and close each knowledge gap

Perform a final full air brake inspection and verbalize each step aloud as in the skills test

Confirm all pressure thresholds, leak limits, and pushrod limits from memory