Why should you inspect the kingpin itself, not just the fifth wheel, when preparing to couple a trailer in a doubles setup?

Pick an answer

1. A worn or damaged kingpin can fail to lock securely even if the fifth wheel itself is in good condition
2. Kingpins are inspected only once a year regardless of use
3. The kingpin has no bearing on how securely the trailer is held once it's fully coupled no matter how worn it becomes over time
4. Only the dolly's kingpin needs checking, never the trailer's own kingpin

Correct!

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