Wyoming CDL — Air Brakes Practice Test 4

1.As a dual-system truck airs up, its low air light and buzzer go quiet when the gauges pass 50 psi. How does that compare with Wyoming's manual?

It is too early: the shut-off value is set by the manufacturer but must be above 60 psiIt is correct: the warning should shut off at half the cut-out pressureIt is too late: the warning should shut off by 30 psiIt is correct: any shut-off point between 20 and 45 psi is acceptable

2.The needle on one of your dash gauges climbs each time you press the brake pedal and drops back when you let up. Which gauge is that?

The application pressure gaugeThe supply pressure gaugeThe oil pressure gaugeThe governor cut-out gauge

3.Which statement about air tank drain valves does NOT agree with the manual?

Every air tank has a drain valve at the bottomA tank with an automatic drain can never be drained by handA manual drain opens with a quarter turn or a pull on a cableAutomatic drains can be had with electric heaters to keep them from freezing

4.Section 11M has you look for fluid and air leaks at the front of the vehicle with the engine off. Why does it say an air leak matters?

It proves the governor's cut-out is set too highIt can point to a failed component in a spot that is hard to inspect, such as the air compressorIt means the air tanks have been drained too oftenIt shows that the alcohol evaporator has run dry

5.In Section 11M's air brake check, you finish the air leakage rate test and go straight to the air warning device test. What does the manual say about the engine at that point?

Restart it and hold a fast idle while you fan the brakesRestart it only if the vehicle is a combinationDo not restart it; leave the key or electrical power onRestart it, then shut it off once the gauge steadies

6.Section 11M's trailer brake check has you pull forward gently with the trailer parking brake engaged and the tractor's parking brake released. Besides testing the brake, what does the manual say this assists with?

Checking the governor's cut-in pressureChecking slack adjuster stroke on the steering axleChecking the air compressor beltChecking the trailer's coupling connection

7.Air is leaking away steadily as you drive a straight truck. According to the figures in Wyoming's Section 5, in what order do things happen as the pressure falls?

The low air warning comes on before 60 psi; the spring brakes come fully on somewhere between 20 and 45 psiThe spring brakes come fully on at 60 psi; the low air warning follows at 45 psiThe safety valve opens at 60 psi; the low air warning follows at 20 psiThe governor cuts out at 60 psi; the spring brakes come on at 100 psi

8.A driver reasons that spring brakes are applied by springs, not air, so they will hold just as well on brakes that are out of adjustment. What does the manual say?

The driver is wrong: spring brake power depends on the brakes being adjusted properlyThe driver is right: springs make up for any slack in the brakesThe driver is right, but only on vehicles built since 1994The driver is wrong: spring brakes stop working whenever the engine is off

9.Which statement about automatic slack adjusters does NOT match the manual?

They adjust themselves during full brake applicationsDifferent manufacturers' adjusters do not all operate the same wayThey are found on every vehicle built since 1994The manual recommends adjusting them by hand as a weekly routine

10.On the stopping distance chart in Wyoming's Section 5, vehicle braking distance is 29 feet at 15 mph. What does the chart list at 30 mph?

58 feet87 feet148 feet115 feet