You have just coupled the second trailer in a doubles set and connected all air lines. The trailer air supply gauge shows a pressure drop that stabilizes at 85 psi instead of climbing to normal operating pressure. What is the most likely cause and correct action?
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ANormal for a cold start; wait five minutes for pressure to build before moving
BThe second trailer's spring brakes are holding the brakes on and drawing excess air; release the parking brake handle
CThe tractor's air compressor is undersized for a doubles combination; reduce to a single-trailer configuration
DA likely air leak at one of the glad hand connections or trailer air lines; inspect and repair before moving
✓ Correct answer: D. A likely air leak at one of the glad hand connections or trailer air lines; inspect and repair before movingThe CDL manual instructs drivers to check for air leaks after coupling by monitoring pressure gauges; a pressure reading that stabilizes below normal operating pressure rather than building indicates a leak that must be found and corrected before driving.
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