Tennessee CDL — Air Brakes Practice Test 7

11.What does a supply pressure gauge tell the driver?

How far the brake shoes have wornHow much pressure you are sending to the brakesHow much pressure is stored in the air tanksHow hot the brake drums have become

12.If one side of a dual air system loses most of its pressure, what happens to your stopping?

Nothing changes; the other system covers all brakesIt takes longer to stop because some brakes are not working fullyThe vehicle stops faster than normalThe parking brakes take over automatically at speed

13.If the air compressor has its own separate oil supply, what should you do before driving?

Check the compressor's oil levelDrain the oil completely so it does not overheatAdd alcohol to the compressor housingDisconnect the v-belt to protect the seals

14.With the engine off and the brakes released, what is the maximum acceptable air leakage for a combination vehicle over one minute?

Less than five psi in one minuteLess than eight psi in one minuteLess than one psi in one minuteLess than three psi in one minute

15.Why should you avoid pressing the brake pedal while the spring brakes are already applied?

The combined spring and air forces could damage the brakesIt would drain the tanks below the cut-in pressureIt would release the parking brakes unexpectedlyIt would trigger the safety valve to open

16.When making a normal stop with a manual transmission, when should you push in the clutch?

As soon as you begin brakingOnly after the vehicle has fully stopped and rolled backAt the same instant you touch the brake pedalOnly once engine speed has fallen close to idle

17.What is the main job of an antilock braking system (ABS)?

It shortens the vehicle's stopping distance on every surfaceIt keeps the wheels from locking up during hard brakingIt replaces the need for a parking brakeIt raises the governor cut-out pressure automatically

18.How is the "stab braking" method performed in an emergency?

Hold steady, light pressure the entire timeApply the parking brake in short burstsApply fully, release when wheels lock, then apply fully again once they rollSteer hard while holding the wheels locked

19.With the engine off and the foot brake fully applied, what air loss rate is acceptable for a single vehicle over one minute?

No more than six psi in one minuteNo more than ten psi in one minuteAny drop is acceptable if the warning stays offNo more than three psi in one minute

20.How do you test that the parking brake will hold?

Rev the engine to full throttle in neutralSet it, then in a low gear gently try to ease forward against itRoll downhill and release it suddenlyPump the brake pedal ten times quickly