After locking the kingpin into the fifth wheel, how can you confirm the connection is secure?

To confirm that the connection between the kingpin and the fifth wheel is secure, pulling gently with the trailer brakes locked is the most effective method. This action allows the driver to check whether the fifth wheel has properly engaged the kingpin without creating any risk of separating the tractor from the trailer.

When the trailer brakes are locked, the trailer remains stationary, and by gently pulling forward, the driver can confirm that the fifth wheel has latched onto the kingpin securely. If the connection is not secure, the tractor might be able to pull away from the trailer, indicating a problem that needs to be addressed. This method ensures that the driver can verify the connection safely and effectively before proceeding on their journey.

Other methods listed, such as pulling the tractor ahead sharply or at high speed, can be unsafe and may not adequately demonstrate whether the connection is secure. Additionally, turning left then right may not provide any meaningful feedback regarding the engagement of the kingpin and fifth wheel. Therefore, pulling gently with the trailer brakes locked optimally ensures that the coupling is secure and safe for travel.