Montana CDL — Air Brakes Practice Test 10

1.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

2.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

3.You pull hard on a slack adjuster during the walk-around and it travels roughly an inch and a half at the point where the push rod attaches. What does the manual say about that brake?

It probably needs adjustmentIt is within limits; up to two inches of travel is acceptableIt shows the automatic drain valve has failedIt means the spring brake is still applied

4.The manual gives two other names for the brake pedal on an air-braked vehicle. Which pair is it?

Foot valve or treadle valveTrolley valve or Johnson barTractor protection valve or trailer air supply controlModulating valve or limiting valve

5.According to the manual, why can't air pressure alone be trusted to hold the emergency and parking brakes on?

Because the air can leak away over timeBecause air reacts more slowly than mechanical partsBecause air pressure would overheat the drums while parkedBecause air-held brakes never need to be adjusted

6.Air pressure has leaked down until the spring brakes apply on a heavily loaded truck. Why does the manual say the stop will be a long one?

Not every axle has spring brakes working on itSpring brakes apply only half of their force when the vehicle is loadedThe governor holds the spring brakes off until the engine stopsHeavy loads keep the brake drums too cool to grip

7.Your test vehicle has primary and secondary air brake systems. For the emergency brake test, what does the manual's inspection section say you must explain to the examiner?

That the secondary system is used only for the trailerThat the valves pop out as soon as either system falls below 100 psiThat there is a backup system, so the valves will not pop out when only one system loses pressureThat dual systems are exempt from the emergency brake test

8.You are unsure whether your truck was built late enough to be required to have ABS. Where does the manual say to look for the date of manufacture?

On the registration card kept in the cabOn the vehicle's certification labelOn the air compressor governor housingOn the back of the yellow parking brake knob

9.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

10.During a trip you find that the safety relief valve on the first air tank has been releasing air. How does the manual treat that?

As normal behavior whenever the governor cuts outAs a reminder that the tanks are overdue for drainingAs proof that the spring brakes are about to applyAs a sign that something is wrong and a mechanic should fix it