CDL EXAM PREP QUESTIONS WITH CORRECT ANSWERS

CDL EXAM PREP QUESTIONS WITH CORRECT ANSWERS

WITH RATIONALES PROFESSOR VERIFIED.

◉ Inspecting Air Brakes. Answer:Seven Step Inspection- check during

-Engine Compartment -Walk Around -Final Air Brake Check

◉ Step 2- Engine Compartment Checks. Answer:Check Air compressor drive belt- condition and tightness

◉ Step 5- Walk Around Inspection. Answer:-Slack Adjusters on S-Cam- Release parking brake, use gloves to pull hard on each slack adjuster -Brakes and Drums

◉ Slack Adjusters should not move more than.... Answer:1 inch where the push rod attaches -All vehicles built since 1994 have automatic slack adjustors

◉ Out of adjustment brakes are.... Answer:the most common problem with air brakes

◉ Brakes and drums must not have cracks longer than... Answer:1 half the width of the frigtion area

◉ Step 7: Final Air Brake Check. Answer:-Test Low Pressure Warning Signal -Check Spring Brakes -Check Rate of Air Pressure Buildup -Test Air Leakage Rate -Check Air Compressor Cut in and out pressure -Test Parking Brake -Test Service Brakes 1 / 2

◉ How to check low pressure warning signal. Answer:Turn off engine, turn electrical power on- step on brake pedal by pushing on brake Low air pressure warning must signal lower than 60 psi

◉ How to Check Spring Brakes. Answer:Step on brake pedal on and off, parking brake valve should pop out when air pressure falls to 20-45 psi.

◉ How to check rate of air pressure buildup. Answer:pressure should build from 85 to 100 psi within 45 seconds pre-1975 single air systems- 50 95 psi in 3 mins

◉ How to check air leakage rate. Answer:fully charged system, 125 psi, turn off engine, release parking brake, and time the air pressure drop loss rate should be less than two psi in one minute (single) three psi in one minute (combo vehicles) shut off engine, chock wheels, release parking brake, apply foot brake and hold for one minute **air pressure should not drop more than 3 lbs in one minute (single) or 4 lbs in one minute (combo)

◉ How to test parking brake. Answer:set parking brake, gently pull against in a low gear and see if it will hold

◉ How to test service brakes. Answer:wait for normal air pressure, release parking brake, move forward at 5 mph, apply brakes firmly using pedal- not any pulling to one side, unusual feel, or delayed stopping action

◉ Controlled Braking. Answer:-apply brakes as hard as you can w/o wheels locking -keep steering movements small -if wheels lock, release brakes and reapply asap

◉ Stab Braking. Answer:apply brakes all the way- release when brakes lock up

When wheels start rolling, apply brakes again

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