New Hampshire CDL — Air Brakes Practice Test 1

11.Rig 1 has ABS on the tractor only. Rig 2 has ABS on the trailer only. Which statement matches what the manual says each rig gains under braking?

Rig 1's trailer is less likely to swing out; Rig 2 should keep steering control and is less likely to jackknifeRig 1 gains nothing; only Rig 2 has more controlRig 1 should keep steering control and is less likely to jackknife; Rig 2's trailer is less likely to swing outBoth rigs stop in half the distance, and neither can skid

12.For the front of the vehicle and engine area on the vehicle inspection test, the manual explains why you look for air leaks. What could an air leak point to?

Tires that have been overinflatedA fuel tank cap that is missingCoolant that is too cold to circulateA failing component in a spot that is not easy to inspect, such as the air compressor

13.After the low air pressure warning comes on, how long does the manual say controlled braking stays possible?

For as long as the engine keeps runningUntil the ABS malfunction lamp lightsFor exactly one more full brake applicationOnly while enough air is left in the tanks

14.Each time you let up on the brake pedal, some compressed air leaves the system and tank pressure drops. What does the manual say makes up for the lost air?

The spring brake chambersThe alcohol evaporatorThe air compressorThe safety relief valve

15.The figure 55 psi turns up several times in the Air Brakes section. Which of these is NOT tied to 55 psi?

The tank pressure before which the low air warning must come onThe minimum pressure to build in both halves of a dual system before drivingThe system pressure below which a wig wag drops into viewThe application pressure at which automatic front limiting valves stop cutting air to the front brakes

16.Two trucks both have alcohol evaporators. Truck A's air tanks have manual drain valves; Truck B's have automatic drain valves. Under the alcohol evaporator passage, which truck still needs its tanks drained by the driver every day?

Truck B onlyBoth trucksNeither truck, because the alcohol removes the waterTruck A only

17.One of the two air leakage tests in the Step 7 check times the pressure drop with your foot off the brake. Which of these is NOT part of setting it up?

Starting with a fully charged air systemHolding the foot brake fully appliedTurning the engine offReleasing the parking brake

18.The final air brake check gives roughly 100 psi for compressor cut-in and roughly 125 psi for cut-out. What reminder does the manual attach to those figures?

Add 10 psi to each figure in cold weatherCheck the manufacturer's specificationsUse them only for vehicles made before 1975Treat them as exact limits that never vary

19.Several faults described in the Air Brakes section are handed to a mechanic or a repair facility. Which of these tasks does the manual say you must do yourself?

Draining manually operated air tanks once each day of driving is overFixing the fault when the safety relief valve releases airCorrecting a brake whose automatic slack adjuster is out of adjustmentRebuilding a governor that will not cut in or cut out

20.The hand check of S-cam slack adjusters starts with parking on level ground and chocking the wheels. Why are the chocks needed for this particular check?

The parking brakes are released for the check, so the chocks are what keep the vehicle from movingThe chocks take the vehicle's weight off the slack adjustersThe chocks keep the air tanks level so the gauge reads trueThe chocks hold the brake shoes against the drums