MD CDL Air Brakes study guide
MD CDL Air Brakes · Work through your exam, one topic at a time.
The Maryland Commercial Driver's License Air Brakes Knowledge Test is the written exam a CDL applicant takes to remove the air brake restriction (the "L" restriction on a Maryland CDL, though always confirm the current restriction code with the MVA) so they can legally operate a commercial vehicle equipped with air brakes. It is for anyone pursuing a Class A or Class B CDL, or upgrading an existing CDL, who expects to drive trucks, tractor-trailers, buses, or other vehicles with air-actuated service, parking, and emergency brakes. The MD CDL Air Brakes study guide has 7 sections and about 2,192 words.
01Air Brake System Components and Their Functions
The Maryland CDL air brake test asks you to name each part of the system and describe what it does when you press or release the pedal. Most questions here are functional: given a symptom, identify the component; given a component, identify its job in the air path.
353 words, about 2 min02Air Supply, Compressor, and Reservoirs
The supply side is what makes everything else work: compressor, governor, dryer, and reservoirs. Maryland tests cut-in and cut-out pressures, build-up time, and the daily drain.
302 words, about 2 min03Brake Pedal Operation, Application, and Release
Pedal feel is a test topic because it explains both how much braking you get and why air brakes feel different from hydraulic brakes. The foot valve is a pressure regulator, not a pump.
320 words, about 2 min04Inspecting and Testing Air Brakes
The pre-trip air brake test is a sequence, and exam questions often ask what a specific reading means or in what order the steps go. Chock the wheels, drain the tanks, start the engine and build pressure.
315 words, about 2 min05Warning Devices, Low Air Pressure Warning, and Emergency Braking
Warning devices are your last clear notice before the spring brakes take over. The exam tests the pressures and what you are supposed to do.
287 words, about 1 min06Parking Brakes and Emergency Stop Procedures
Parking and emergency-stop questions check whether you know which control does what and when it is safe to release it. The yellow diamond parking valve is pulled out to apply and pushed in to release.
330 words, about 2 min07Safe Driving Practices with Air Brakes
Air brakes stop a heavy vehicle, but not the way hydraulic brakes do. Driving questions test following distance, downgrade technique, and what changes when brakes get hot or wet.
285 words, about 1 min