Montana CDL — Air Brakes Practice Test 8

1.It is January and your truck has an alcohol evaporator and manually drained air tanks. A coworker says the evaporator means you can skip draining the tanks. What does the manual say?

He is right; alcohol dissolves the water and oil in the tanksHe is wrong; the tanks still need draining every day to remove water and oilHe is right, but only while the temperature stays below freezingHe is wrong; with an evaporator the tanks must be drained after every stop

2.The governor cut the compressor out at about 125 psi. After several brake applications the gauge reads 110 psi and is still dropping. Going by the manual's typical figures, what is the compressor doing?

Pumping at full output, because any drop below cut-out restarts itPumping at half output until the tanks are full againVenting air through the safety valveNot pumping yet; the governor lets it start again at around 100 psi

3.Your vehicle applies its spring brakes with a modulating control valve on the dash. How does the manual say to park it?

Push the lever to the end of its travel and lock it there with the locking deviceMove the lever halfway so the springs are not overstressedLeave the lever released and rely on wheel chocks alonePump the lever until the low air warning comes on

4.In the air leakage rate test on the vehicle inspection test, you shut off the engine, release the brakes and press the foot brake all the way down. When does the manual's one-minute count begin?

The moment the engine is shut offAfter the gauge needle settles following the first drop caused by the brake applicationWhen the low air warning comes onAfter the parking brake valve pops out

5.Your air pressure builds more slowly than the manual's standard during the pre-trip check. What does the manual say could happen if you drive anyway?

The governor will raise its cut-out pressure to compensateThe safety valve will open at 150 psiThe brakes will apply harder than normalPressure may fall too low on the road and force an emergency stop

6.On an older ABS system, the yellow malfunction lamp is still lit as you pull away from a stop. According to the manual, when might that still be normal?

For the first 55 miles of every tripWhenever the parking brake knob is pushed inUntil the governor reaches its cut-out pressureWhile your speed has not yet passed five mph

7.A dual air brake system splits the regular brakes between two systems. One usually handles the rear axle or axles. What does the manual say the other one handles?

The front axle brakes, and possibly one rear axleOnly the trailer brakesOnly the spring brakesThe same rear axles, as a duplicate

8.A driver wants a passenger endorsement and will drive a bus that has air brakes. Besides the test on Sections 2 and 4, what does the manual say this driver must also pass?

A knowledge test on Section 9, Hazardous MaterialsA knowledge test on Section 7, Doubles and TriplesNo other knowledge testA knowledge test on Section 5, Air Brakes

9.A driver makes a habit of manually adjusting his truck's automatic slack adjusters every week. Besides hiding a mechanical problem, what does the manual say this routine is likely to cause?

Higher governor cut-out pressureFaster air pressure buildupA longer push rod stroke limitEarly wear of the adjuster itself

10.Which problem does the manual say roadside inspections turn up more often than any other?

Air tanks that have not been drainedLow alcohol level in the evaporatorBrakes that are out of adjustmentBurned-out ABS malfunction lamps