OR CDL Air Brakes study plan

Identify and state the function of each major air brake component: compressor, governor, reservoirs, drain cocks, safety valve, check valves, foot valve, brake chambers, slack adjusters, and push rods.

Trace the path of compressed air from the compressor through the governor cut-in and cut-out cycle to the service brake chambers and back to atmosphere.

Explain how the governor controls compressor loading and unloading and describe what happens when the governor fails.

Distinguish the roles of the supply reservoir and the primary and secondary circuits by function, not by memorized labels.

Explain the split of the dual air brake system into primary and secondary circuits and which brake positions each circuit typically protects.

Describe how a failed circuit still allows the other circuit to stop the vehicle, and state what the driver should expect in the cab.

Explain the purpose and operation of the spring brake (parking brake) and how air pressure releases it.

Explain the role of the safety valve, check valves, and the low-pressure warning device in protecting the system.

Describe the emergency (push-to-set) and parking release controls and predict what happens to the spring brakes during a slow pressure loss.

Perform the seven-step air brake inspection sequence in order: leakage check, low-pressure warning, spring brake test, and the remaining pre-trip steps.

List the specific items checked at each step, including drain cocks, slack adjuster play, brake chamber condition, hoses, and lines.

Demonstrate the ability to check slack adjuster free play and state the acceptable limit.

Identify common defects that would place a vehicle out of service during a pre-trip inspection.

Explain how to perform the static leakage test and state the acceptable pressure loss limits for a single vehicle and for a combination vehicle.

Describe the low-pressure warning test and the pressure at which the warning must activate.

Explain the spring brake test and the conditions under which the spring brakes must apply automatically.

Describe how to perform the applied leakage test with the brakes fully applied and what a failure indicates.

Interpret a failed check and decide whether the vehicle is safe to drive.

Combine the inspection sequence and the four system checks into one continuous pre-trip routine performed from memory.

Practice reciting the pass/fail criteria for each check without notes.

Diagnose a hypothetical fault (for example, pressure loss above the limit or a warning that does not sound) and state the correct action.

Explain how ambient conditions such as cold weather or a slow compressor build-up affect the checks.

Explain how to use the brakes on a downgrade, including selecting a safe gear before the descent and using controlled, steady applications.

Describe the correct use of the trailer hand valve and why it should not be used for parking.

Explain how to test the brakes after driving through water and how to dry them out.

Describe the effect of speed, load, and road surface on stopping distance and how to adjust following distance.

Explain the proper procedure for stopping and parking, including setting the parking brake and using wheel chocks.

Explain the correct response to a brake failure: downshift, use the emergency/parking brake gradually, and look for an escape route.

Describe how to use the spring brakes as an emergency stopping tool and the risk of applying them too abruptly.

Explain what to do if the low-pressure warning sounds while driving.

Describe how to handle a brake fire and why water should not be used on a hot brake.

Explain the correct response to a loss of air pressure in one circuit of a dual system.

Review all six domains using the week 1 through 7 deliverables and correct every error found.

Re-take practice questions for each domain and record the score per domain.

Re-teach the weakest domain from memory in writing, without notes.

Confirm the full inspection and check sequence and the emergency procedures are recalled correctly under time pressure.