CDL Doubles and Triples Practice Test 2
What is the correct position of the converter dolly air drain valve during the pre-trip inspection?
Which of the following driving practice is recommended for doubles/triples?
Allow more following distance. Doubles and triples have longer stopping distances and require more following distance. The heaviest semitrailer should go in the first position, not the rear position.
What is the correct amount of space between the upper and lower parts of the fifth wheel on the dolly when coupled to a trailer?
No space. There should be no space between the upper and lower fifth wheel after coupling. If there is space, it indicates a problem such as the kingpin resting on top of the closed fifth wheel jaws.
What should be inspected on the landing gear for doubles/triples?
Where will you find shut off valves on doubles and triples?
Both service and emergency air lines. Shut-off valves (sometimes referred to as cut-out cocks) are located at the back of trailers used to tow other trailers. They are used for both the service and emergency air lines.
If your tractor protection valve malfunctions, what could happen?
All of the above. The trailer protection valve's purpose is to keep air in the brake system in case the trailer brakes away or develops a bad leak. If the trailer protection valve malfunctions, then air could be drained away from t
What is the proper procedure to test the trailer service brakes?
Use trolley valve to apply brakes and check to see if you feel the trailer brakes come on. To test the trailer service brakes you should check for normal air pressure, release the parking brakes, and move the vehicle forward slowly
Which trailer of a triple trailer is most likely to roll over?
The rear trailer. The rearward amplification for a triple trailer is 3.5. This means that the rear trailer of a triple is 3.5 times more likely to rollover as a standard five-axle trailer.
What is the correct trailer height when you connect the converter dolly to the rear trailer?
Trailer is slightly lower than the center of the fifth wheel. The trailer should be low enough that it is raised slightly when the tractor is backed under it. If the trailer is too low, the trailer nose may become damaged. If the
Which of the following procedures should you do when connecting the converter dolly to the rear trailer?
A and C. When connecting the converter dolly to the rear trailer, the shut-off valves on the last trailer should be CLOSED. The shut-off valves at the rear of the first trailer (and dolly if it is equipped) should be OPEN.
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