CDL - Combination Vehicle Practice Test Questions And Solutions Verified 100% Correct

CDL - Combination Vehicle Practice Test Questions And Solutions Verified 100% Correct The front trailer supports are up, and the trailer is resting on the tractor. Make sure that 1. there is enough clearance between the upper and lower fifth wheel 2. there is enough clearance between the tractor frame and the landing gear 3. the safety latch is in the unlocked position - ANSWER there is enough clearance between the tractor frame and the landing gear The trailer hand valve works the trailer brakes. Which of these statements is true? 1. the foot brake sends air to all the brakes on the vehicle ( including the trailer(s)) 2. The trailer hand valve should be used only to test the trailer brakes 3. all the above - ANSWER all the above Where should the tractor be when you inspect the landing gear after uncoupling the trailer? 1. With the fifth wheel directly beneath the kingpin 2. completely cleared from the trailer 3. with the tractor frame under the trailer - ANSWER with the tractor frame under the trailer After you lock the kingpin into the fifth wheel, you should check the connection by pulling 1. the tractor ahead gently with the trailer brakes locked 2. forward 50 feet, then turning right, and then left 3. the tractor ahead sharply to release the trailer brakes - ANSWER the tractor ahead gently with the trailer brakes locked At night, when a vehicle is carrying a load that extends four feet or more beyond the rear of the body, there must be ________ at the extreme end of the load. 1. red lights 2. red flags 3. a red flag - ANSWER red lights Which type of truck-trailer combination has the greatest chance of a "crack-the-whip" rollover? 1. A tractor pulling three trailers 2. A single tractor trailer 3. A tractor pulling two trailers - ANSWER A tractor pulling 3 trailers Air and electrical lines from the tractor to the trailer should be... 1. pulled tight with very little slack 2. secured but with enough slack for turns 3. resting on the frame of the tractor. - ANSWER secured but with enough slack for turns Compared with a straight truck or bus, there are ________ things to inspect in combination vehicles. 1. fewer 2. more 3. the same number of - ANSWER more What is the emergency air line for? 1. To engage the trailer brakes in case of air pressure loss 2. To have extra air pressure in case you need it 3. To engage the front brakes of the tractor in case of an emergency - ANSWER To engage the trailer brakes in case of air pressure loss The tractor protection valve will close and the trailer _______ brakes will come on when there is a major leak in the brake line . 1. parking 2. service 3. emergency - ANSWER emergency A trailer is most likely to jackknife when it is ... 1. loaded to full capacity 2. overloaded 3. empty - ANSWER empty When you are uncoupling a loaded trailer, lower the landing gear until it ... 1. reaches the ground 2. makes firm contact with the ground 3. makes contact with the ground, and leave the trailer off the fifth wheel - ANSWER makes firm contact with the ground How much space should there be between the upper and lower fifth wheel after coupling? 1. Just enough to see light through it 2. About 1/4 inch 3. None - ANSWER none After you have coupled the trailer, you should start to raise the landing gear by using 1. low gear 2. high gear 3. intermediate gear - ANSWER low gear The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means that 1. the parking lock is off and you may drive away 2. the coupling is not right and should be fixed before you drive the coupled unit 3. the trailer will not swivel on the fifth wheel - ANSWER the coupling is not right and should be fixed before you drive the coupled unit When checking the trailer emergency brakes, make sure that the tractor protection control valve is placed in the _______ position. 1. normal 2. emergency 3. neutral - ANSWER emergency You should use chocks when parking a trailer without spring brakes because 1. if the air supply leaks away, there will be no brakes 2. some states require chocking of trailer wheels 3. you dont want the trailer rolling down a hill - ANSWER if the air supply leaks away, there will be no brakes You are uncoupling a trailer. After you shut off the trailer air supply and lock the trailer brakes, you should 1. begin to lower the trailer landing gear 2. immediately apply your tractor parking brakes 3. back up gently to ease pressure on the fifth wheel locking jaw - ANSWER back up gently to ease pressure on the fifth wheel locking jaw While you are driving, your emergency air line breaks or gets pulled apart. The loss of pressure will cause the 1. air compressor to unload instead of pumping air 2. trailer emergency brakes to come on 3. trailer supply valve to open - ANSWER trailer emergency brakes to come on