Oklahoma CDL — Air Brakes Practice Test 3

1.When someone suddenly pulls out in front of you, how should you brake?

So the vehicle stays straight and you can still steer if neededBy locking all the wheels immediatelyBy steering hard while pumping the pedalBy releasing the brakes and coasting

2.What advantage do the air storage tanks give you if the compressor quits pumping?

The parking brake control releases itself automaticallyEnough compressed air is still on hand to apply the brakes a number of timesThe governor raises its cut-out setting to make up the differenceThe brakes switch over to hydraulic pressure from the power steering pump

3.Truck tractors with air brakes built on or after which date are required to have antilock brakes?

March 1, 1997March 1, 1975January 1, 1994July 1, 2017

4.Before driving a vehicle with a dual air system, what minimum pressure should build in both the primary and secondary systems?

50 psi100 psi150 psi200 psi

5.What must you always do before leaving your vehicle unattended?

Drain the air tanks completelyRelease the parking brakes to spare the springsApply the parking brakes or chock the wheelsLeave the engine running to keep pressure up

6.In a dual air system with the engine at operating rpm, air pressure should build within which range and time?

From 50 to 90 psi within three minutesFrom 85 to 100 psi within 45 secondsFrom 20 to 45 psi within ten secondsFrom 100 to 125 psi within five minutes

7.You are braking hard in a combination where antilock brakes are fitted to the tractor but not the trailer. What should you be watching for?

The trailer wheels locking, which you fix by pressing the pedal even harderThe trailer swinging out, which calls for easing off the brakes when you can do it safelyThe ABS lamp going dark, which shows the tractor brakes have failedThe steering wheel tugging to the right, which shows the trailer brakes are dragging

8.The total stopping distance for an air brake vehicle is made up of which four parts?

Perception, reaction, brake lag, and braking distancePerception, reaction, cut-in, and cut-out distanceSteering, skid, drift, and braking distanceWarning, buzzer, spring, and braking distance

9.In a dual air brake system, what happens to stopping ability if one of the two systems is very low on pressure?

Braking becomes stronger on all axlesThe parking brakes release on their ownEither the front or rear brakes won't work fully, so stopping takes longerThe compressor shuts down permanently

10.What is the job of an alcohol evaporator in some air brake systems?

To cool the air compressor during heavy useTo boost the pressure sent to the front brakesTo scrub oil residue out of the brake chambersTo reduce the risk of ice forming in the valves in cold weather