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.
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.
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.
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.
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
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.
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.
1st and 3rd options. 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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CDL Tanker Test #1
