California CDL — Air Brakes Practice Test 3

11.You must leave a vehicle that is not equipped with spring brakes parked and unattended. What must you do to keep it from moving?

Use wheel chocks to keep the vehicle from movingLeave the service brake pedal blocked downKeep the engine running so the compressor maintains pressureTurn the front wheels sharply and leave it in neutral

12.Total stopping distance for a vehicle with air brakes is made up of which four factors?

Perception, reaction, brake lag, and effective braking distancePerception, reaction, coasting, and skidding distanceReaction, brake lag, downshift, and coasting distancePerception, signaling, braking, and following distance

13.Some air compressors carry their own oil supply instead of being lubricated by engine oil. What should you do on a vehicle with that kind of compressor?

Drain the compressor oil at the end of every shiftCheck the compressor's oil level before you driveAdd alcohol to the compressor oil in cold weatherNothing — a self-lubricated compressor never needs checking

14.You are driving a vehicle with a dual air brake system and one of the two systems loses pressure. What should you expect, and what should you do?

Braking is unaffected; finish your trip and report it laterStopping distance increases; stop safely and get the system fixed before driving onThe vehicle cannot be stopped at all; use the escape rampOnly the trailer brakes are lost; drive slowly to the destination

15.The safety relief valve on the first air tank opens and releases air. What does that tell you?

The system is working normally and no action is neededThe tanks are full of water and need to be drainedSomething is wrong, and a mechanic should fix the faultThe spring brakes are about to apply automatically

16.The low air pressure warning signal on a vehicle with air brakes must come on before air pressure in the tanks falls below what level?

20 psi100 psi80 psi55 psi

17.It is freezing outside and your brakes are very wet. Before you park, what does the handbook suggest doing about the wet brakes?

Drag the brakes gently in a low gear so the heat dries them outSet the parking brakes right away so the linings cannot freezeFan the brake pedal with the engine off to blow the water outDrain the air tanks to remove the water from the brake drums

18.How do brakes that are out of adjustment contribute to brake fade on the rest of the vehicle?

They stop doing their share of the work, so the other brakes overheatThey grip harder than the others and lock their wheelsThey leak air and trigger the low pressure warningThey cause the governor to cut out the compressor

19.You take your CDL skills (drive) test in a vehicle that is not equipped with air brakes. What happens to your license?

Nothing — air brakes only matter for the knowledge testYour CDL is issued with an air brake restrictionYou must retake the entire CDL program within 30 daysYou are limited to intrastate driving only

20.During an inspection of s-cam brakes with a manual slack adjuster, you pull hard on each slack adjuster (with the parking brakes released and wheels chocked). When does a slack adjuster need adjustment?

If it moves at all when pulled by handIf it moves more than about an inch at the point where the push rod connectsIf it moves more than about three inches where the push rod attachesOnly if the brake drum shows cracks