Florida CDL — Air Brakes Practice Test 5

1.Why must air storage tanks be drained regularly if they only have manual drain valves?

To keep the tanks from over-pressurizing the governorTo remove the water and compressor oil that collect inside themTo recharge the spring brake chambersTo test the low air pressure warning device

2.A driver who skips or fails the air brakes knowledge test can still earn a CDL, but it will:

Expire after 90 daysBe valid only for automatic transmissionsCarry the L restriction prohibiting vehicles with full air brakesRequire a co-driver in air-braked vehicles

3.At 55 mph, how much extra distance does air brake lag alone add to your stop?

About 12 feetAbout 32 feetAbout 100 feetAbout 216 feet

4.While driving a truck with a dual air brake system, pressure in one of the two systems falls dangerously low. What should you expect?

One end of the vehicle, front or rear, will brake at reduced power and your stop will take longerThe healthy system automatically doubles its pressure to make up the differenceSpring brakes clamp instantly on every axle of the truckBraking is unaffected, because both systems draw from one shared tank

5.How does a Z restriction on a CDL differ from an L restriction?

Z applies only to school buses, while L applies to all CMVsZ means the skills test was taken in a vehicle with air-over-hydraulic brakes, and it still bars full air brake vehiclesZ permits full air brakes but only in daylightZ is a temporary restriction that clears automatically after one year

6.During your pre-trip you find cracked brake drums and an audible air leak at a brake chamber. What are you required to do?

Drive slowly and get the repairs done at your destinationLog the defect and continue if the low-air warning worksNot drive the vehicle until the brake defects are repairedDisconnect the leaking chamber and rely on the remaining brakes

7.The yellow ABS malfunction lamp stays lit after the start-up bulb check and is still on once you are rolling. What does that tell you?

The parking brakes are dragging and overheatingThe governor has quit cycling the air compressorThe truck has no braking ability at all and must be towedAntilock protection may be gone at one or more wheels, though the normal brakes still work

8.As part of the final air brake check, how do you confirm that the parking brake will actually keep the vehicle from moving?

Set it while rolling at about five mph and check that you stopPump the service brake pedal and watch the supply pressure gaugeApply it while stopped, then ease forward in a low gear to see if it holdsRelease it on a slope with the engine off and see if the truck rolls

9.What does the stop light switch do in an air brake system?

It shuts off the compressor at cut-out pressureIt releases the spring brakes when air pressure is restoredIt dims the headlights during hard brakingIt turns on the brake lights when you apply the air brakes

10.A bad air leak drains your tractor's tanks while you are driving. What will happen once pressure falls into the 20–45 psi range?

The compressor will switch to a backup tank automaticallyThe service brakes will grip harder than normalNothing changes until pressure reaches zeroThe spring brakes will apply on their own