Wyoming CDL — Air Brakes Practice Test 3

1.A truck tractor and a trailer, both with air brakes, were each built in June 1997. Going by the dates in the manual, which of them was required to have ABS?

Both of themOnly the tractorOnly the trailerNeither of them

2.Which test in the Step 7 final air brake check is done with the vehicle rolling forward?

The air leakage rate testThe service brake testThe low pressure warning signal testThe governor cut-in and cut-out check

3.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

4.Controlled braking and stab braking start out differently. Which statement gets the difference right?

Controlled braking stops just short of locking the wheels; stab braking applies the brakes all the wayControlled braking applies the brakes all the way; stab braking stops just short of locking the wheelsBoth begin with the lightest pedal pressure that slows the vehicleControlled braking uses the parking brake control; stab braking uses the brake pedal

5.Going by the total stopping distances on the chart in Wyoming's Section 5, how much shorter is a stop from 45 mph than a stop from 55 mph?

76 feet141 feet65 feet310 feet

6.Section 5 describes more than one kind of parking brake control. Which pairing of a control and its purpose matches the manual?

Modulating control valve: releasing the spring brakes with air from a separate tankSpring-loaded valve on a dual parking control: applying the spring brakes graduallyModulating control valve: applying the spring brakes gradually if the service brakes failYellow push-pull knob: limiting air to the front brakes on slippery roads

7.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

8.Section 5 of Wyoming's manual says the low air warning has to come on before tank pressure drops below 60 psi. What mark do the manual's vehicle inspection test sections give for the low air warning devices?

Before 55 psi, or the level the manufacturer specifiesBefore 60 psi, with no allowance for the manufacturerBefore 45 psi, or half the governor cut-out pressureBefore 85 psi on every type of vehicle

9.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

10.ABS is meant to prevent skids and jackknifes that braking sets off. Which kind of skid do the manual's ABS safety reminders say it will NOT prevent?

A skid from locking the steering wheels under hard brakingA trailer swing set off by overbrakingA jackknife caused by braking too hard on a wet roadA skid from spinning the drive wheels or taking a turn too fast