CDL Class A Air Brakes Test Practice Questions and Answers Verified 100% Correct| Latest Updates 2027|

CDL Class A Air Brakes Test Practice Questions and Answers Verified 100% Correct| Latest Updates 2027| To determine if slack adjusters need adjustment... A) apply the service brakes and release the parking brakes B) apply both the service and parking brakes C) pull out the automatic slack adjustment control knob D) release both the service and parking brakes - ANSWER -D You should avoid using the parking brake... A) on steep hills B) if the air pressure is low C) when the brakes are hot D) any time you park - ANSWER -C A combination vehicle air brake system should not lose air faster than... A) 2 psi per minute B) 3 psi per 30 seconds C) 3 psi per minute D) 4 psi per minute - ANSWER -C Some air brake systems have an alcohol evaporator which helps... A) reduce the risk of ice in the air brake valves during cold weather B) remove oil from the air lines C) reduce the risk of water in the air brake valves in warm weather D) remove fuel from the air lines - ANSWER -A Air tanks should be drained... A) once a week B) once a day C) every 4 hours D) every 2 or 3 days - ANSWER -B To check the air compressor governor "cut in" and "cut out" pressures... A) run the engine at a fast idle B) step on and off the brake to reduce the tank pressure C) monitor the air pressure gauge D) all of the above - ANSWER -D Air tanks should be drained... A) at the end of each day or shift B) to keep sludge from clogging brake system valves C) manually when automatic devices fail D) all of the above - ANSWER -D The service brake system... A) is an official vehicle inspection B) applies and releases the brakes by using the brake pedal under normal driving C) are the valves that keeps the air tank pressure serviced D) is only on vehicles with hydraulic brakes - ANSWER -B Air brakes take longer to stop than hydraulic brakes because... A) the reaction time is longer for the driver B) it takes longer for the air to flow through the lines C) the linings get hotter more quickly D) none of the above - ANSWER -B The driver must be able to see a warning that is given before air pressure in the service air tanks falls below: A) 80 psi B) 40 psi C) 20 psi D) 60 psi - ANSWER -D If the air compressor should develop a leak, what keeps the air in the tanks? A) the tractor protection valve B) the emergency relay valve C) the one way check valve D) the air compressor - ANSWER -C If your air compressor stops working... A) you will lose your brakes immediately B) the brakes will immediately lock up C) you'll still have air pressure left in the air tanks D) your brakes won't be affected - ANSWER -C The safety valve in the air compressor tank is set to open at... A) 150 psi B) 200 psi C) 100 psi D) 175 psi - ANSWER -A An air tank is equipped with a drain valve to remove... A) air and water B) oil and air C) water and oil D) dirt and oil - ANSWER -C The application pressure gauge shows the driver how much pressure: A) has been used on the trip B) is in the air tanks C) none of these D) is being applied to the brakes - ANSWER -D Brake drums... A) are bolted to the wheels B) are located at each end of the vehicle's axles C) hold the brake shoes and linings D) all of the above - ANSWER -D To test the air leakage rate you should... A) leave the engine running and release the service brake B) turn off the engine and release the service brake C) charge the air system and leave the engine running D) depress the brake pedal and monitor the air pressure gauge - ANSWER -B A dual air brake system... A) has two air brake systems and one set of controls B) takes less time to build air pressure C) has one set of air tanks and hoses D) must have two warning alarms - ANSWER -A Oil and water usually collected in compressed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks? A) after every working day B) after every four hours of service