Kentucky CDL — Air Brakes Practice Test 7

11.What is "brake lag" in an air brake system?

The delay while the parking brake releasesThe short delay while air travels to the brakes after you press the pedalThe time to build tank pressure at startupThe distance covered before you spot a hazard

12.Why can needlessly pumping the brake pedal be dangerous on an air brake vehicle?

It overheats the air compressorIt can bleed off air faster than the compressor rebuilds itIt locks the spring brakes onIt sets off the ABS warning lamp

13.On vehicles built before 1975, what did the "slippery" setting of a front brake limiting valve do?

It increased pressure to the front brakesIt shut off the rear brakesIt locked the spring brakesIt reduced front-brake air pressure to half its normal level

14.During a walk-around, a manually adjusted s-cam slack adjuster probably needs adjustment if it moves more than about how much?

About one inchAbout three inchesAbout half an inchAbout six inches

15.Why should you avoid pressing the brake pedal while the spring brakes are already applied?

The combined spring and air forces could damage the brakesIt drains the alcohol evaporatorIt resets the ABS lampIt releases the parking brakes

16.How do you test the parking brake during the air brake inspection?

Rev the engine and listen for itDrain the tanks and watch the gaugePress the brake pedal five timesSet the parking brake, then ease forward against it in low gear

17.Which statement about ABS and your normal brakes is correct?

It replaces your normal service brakesIt always shortens your stopping distanceIt works only while parkingIt is an add-on that does not change your normal braking ability

18.What should you do as soon as the low-air warning light and buzzer come on?

Keep driving and watch the gaugePump the brakes to rebuild pressurePull over and stop safely at once, while you still have enough air to control the brakesRelease the parking brake control

19.A manually operated air-tank drain valve should be emptied how often?

Only during scheduled maintenanceAt the end of each driving dayAbout once a weekOnly in freezing weather

20.When checking governor cut-in and cut-out during the final air brake check, at about what pressures should the compressor start and stop?

Start near 55 psi and stop near 100 psiStart near 20 psi and stop near 45 psiStart near 125 psi and stop near 150 psiStart near 100 psi and stop near 125 psi