CDL Air Brake Practice Test PRACTICE WITH 100% VERIFIED ANSWERS!!Get a pass on your first trial!!

The parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like: a. Fluid pressure b. Spring pressure c. Air pressure d. Any of the above - correct answers️️b. Spring pressure A straight truck or bus air brake system should not leak at a rate of more than __ psi per minute with the engine off and the brake released. a. 1 b. 2 c. 3 d. 4 - correct answers️️c. 3 Your vehicle has dual air brake system. If low air pressure warning comes on for the secondary system or for one system, you should: a. Bring the vehicle to a safe stop and continue only when the system is fixed. b. Reduce your speed, and test the remaining system while under-way. c. Reduce your speed, and drive to the nearest garage for repairs. d. Continue at normal speed if only the secondary system fails. - correct answers️️a. Bring the vehicle to a safe stop and continue only when the system is fixed. If your vehicle has an alcohol evaporator, it is there to: a. Rid the wet tank of alcohol that condenses and sits at the bottom. b. Eliminate the need for daily tank draining. c. Boost tank pressure the same way that superchargers boost engines. d. Reduce the risk of ice in the air brake valves in cold weather. - correct answers️️d. Reduce the risk of ice in the air brake valves in cold weather. Air braking takes more time than hydraulic because air: a. Brakes use different brake drums. b. Takes more time to flow through the lines than hydraulic fluid. c. Brakes require heavier return springs. d. Is always leaking through airline fittings. - correct answers️️b. Takes more time to flow through the lines than hydraulic fluid. The brake pedal in an air brake system: a. Controls the speed of the air compressor. b. Always needs to be held down halfway during normal driving. c. Controls the air pressure applied to put on the brakes. d. Is connected to slack adjusters by a series of rods and linkages. - correct answers️️c. Controls the air pressure applied to put on the brakes. With air brake vehicles, the parking brakes should be used: a. Whenever you leave the vehicle unattended. b. To hold your speed when going downhill. c. As little as possible. d. Only during pre and post-trip inspections. - correct answers️️a. Whenever you leave the vehicle unattended. For emergency stab braking, you should: a. Pump the brake pedal rapidly and lightly. b. Press on the brake pedal as hard as you can, release the brakes when the wheels lock, and when the wheels start rolling put on the brakes fully again. c. Brake hard until the wheels lock, then get off the brakes for as much time as the wheels were locked. d. Press hard on the brake pedal and apply full hand valve until you stop. - correct answers️️b. Press on the brake pedal as hard as you can, release the brakes when the wheels lock, and when the wheels start rolling put on the brakes fully again. If your truck or bus has dual parking control valves, you can use pressure from a separate tank to: a. Release the spring emergency/ parking brakes to move a short distance. b. Apply more brake pressure if the main tank is getting low. c. Stay parked twice as long with your service air pressure. d. Balance the service brake system whenever you are parked. - correct answers️️a. Release the spring emergency/ parking brakes to move a short distance.