CDL Combination Vehicles KeY Compulsory Exam Questions And CORRECT Answers

How should you test the tractor semi trailer combination for being properly coupled? Pull gently forward in low gear against the locked trailer brakes, then inspect your coupling. When coupling to the trailer, how far do you back up before stopping the first time? Until the fifth wheel plate just touches the trailer. What do you check before backing under the trailer? Make sure the trailer brakes are set. Air lines on a combination vehicle are often colored to keep them from getting mixed up. What color is the emergency line and what color is the service line? Red and blue. After you back up to the trailer and the fifth wheel plate touches the trailer, you set the tractor park brake, get out and hook up the emergency and service air lines. Then what do you do before backing under the trailer? Supply air to the trailer system, then pull out the trailer air supply knob to fully set the trailer brakes