Wyoming CDL — Air Brakes Practice Test 6

11.You are about to pull out in a truck with a dual air system. The primary gauge reads 105 psi and the secondary reads 90 psi. Are you ready to drive?

Yes, because the two readings average close to 100 psiYes, because only the primary system has to reach 100 psiNo, both systems should build to at least 100 psi firstNo, both systems have to reach 150 psi first

12.Which pairing of a pressure figure and what happens there matches Wyoming's Section 5?

About 100 psi: the low air warning comes onAbout 125 psi: the spring brakes come fully onUsually 150 psi: the safety relief valve opensAbout 60 psi: the governor cuts the compressor out

13.Which statement about the safety relief valve does NOT match the manual?

It is fitted to the first tank that receives air from the compressorIts usual opening pressure is 150 psiIt decides when the compressor starts and stops pumpingIf it lets air out, a mechanic should fix the fault

14.Which pair of tests in the Step 7 final air brake check does the manual have you begin by shutting the engine off?

The governor cut-in and cut-out check and the pressure buildup checkThe parking brake test and the service brake testThe air leakage rate test and the low pressure warning signal testThe pressure buildup check and the service brake test

15.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

16.Which statement about front brake limiting valves does NOT match the manual?

Some vehicles made before 1975 have one with a control in the cabThe "slippery" setting cuts normal front brake air pressure in halfAutomatic versions cannot be controlled by the driverUsing one gives the vehicle more stopping power on ice

17.Which of these is NOT part of the Air Gauge and Governor Cutoff Check, the first item in Section 11M's air brake check?

Chocking the wheelsConfirming that the air gauge worksIdentifying the cutoff pressure for your vehicleHolding the foot brake down for one minute

18.S-cam brakes and wedge brakes use different parts to move the brake shoes. What is the end result in both designs?

A disc is clamped between two lining padsThe shoes are drawn together, away from the drumThe drum is squeezed inward onto the axleThe shoes are pushed apart until they press on the inside of the drum

19.A driver figures that careful footwork on the pedal can do everything ABS does. How does the manual compare the two when a wheel is about to lock?

ABS and a skilled driver respond at about the same speedABS responds more slowly, but with more braking forceABS only warns the driver, who must then ease off the pedalABS works far faster than a driver can respond

20.Wig-wag low air warnings come in an automatic type and a manual reset type. How do they differ once pressure is back above the warning level?

The automatic arm has to be pushed up by hand; the manual reset arm rises by itselfBoth arms stay down until the engine is shut offThe automatic arm rises out of view by itself; the manual reset arm has to be put out of view by handThe automatic arm sounds a buzzer; the manual reset arm lights a red lamp