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Daily inspection test
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8. Coupler is insecure or movement exceeds prescribed limit

You must know the symptoms of couplers that are loose or are developing abnormal amounts of movement, methods for measuring the amount of movement or having it measured, and that a vehicle has this major defect when:

    1. Movement between the upper and lower coupler of a fifth wheel is more than 1/2 in. (13mm) in the forward/rearward direction.
    2. Movement between the pintle hook and a drawbar eye is more than 3/8 in. (10mm) in the forward/rearward direction.


    • Position yourself to be able to see the coupler assembly and the related mounting structure and attachments.
    • Visually check for evidence of damaged, broken, cracked, loose or missing components.
    • State what is being checked.
    • Apply trailer brakes and release tractor brakes.
    • Verbally state when in or after coupling, “I will feel for excessive play/movement.”
    • Verbally describe the process to check and measure coupler movement: tractor trailer combination only.
    • Apply trailer brakes and, using the power train, gently pull tractor as far forward as possible.
    • Mark the fifth wheel with chalk or similar marking.
    • Use the power train to move the tractor rearward against the trailer as far as possible.
    • Observe the distance between the markings placed on the fifth wheel and confirm it is less than 1/2 in. (13 mm) for fifth wheel or 3/8 in. (10 mm) for pintle hook.