Oklahoma CDL — Air Brakes Practice Test 7

11.If a truck's air compressor carries its own separate oil supply, what should the driver do before setting out?

Check the compressor's oil levelDrain the compressor of all its oilDisconnect the compressor drive beltPour alcohol into the compressor housing

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

The temperature of the brake drumsHow much pressure is being applied to the brakesThe wear level of the brake liningsHow much pressure is stored in the air tanks

13.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

14.At roughly what pressure is the air system's safety relief valve usually set to open?

55 psi100 psi150 psi200 psi

15.After you have selected the correct low gear for a long downgrade, how should you use the service brakes?

Ride the pedal with light steady pressure for the whole descentLeave them alone entirely and let the engine do all the slowingSqueeze hard enough to feel a clear drop in speed, then let off once you are roughly five mph under your safe speedTap the pedal quickly several times a minute no matter what your speed is

16.In a vehicle without ABS, what happens when the steering-axle wheels lock up during hard braking?

The vehicle stops in a much shorter distanceYou lose steering controlThe parking brakes release automaticallyThe compressor cuts out to protect the tanks

17.When should you avoid setting the parking brakes?

Whenever the vehicle is fully loadedWhen the brakes are very hot or very wet in freezing temperaturesAny time the engine is still runningWhenever you park on level ground

18.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

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

It will drain the air tanks instantlyThe combined spring and air forces could damage the brakesIt disables the low air pressure warningIt releases the parking brakes without warning

20.On air-operated disc brakes, what component does the job that an s-cam does on drum brakes?

A power screw that pinches the rotor between the caliper's lining padsA wedge shoved in between the ends of two brake shoesAn electric solenoid managed by the antilock computerA small hydraulic master cylinder bolted to the axle