Module 3: Coupling and Uncoupling
Coupling Procedure
2. The trailer kingpin should also be inspected prior to coupling. The kingpin plate should be fully reinforced and of sufficient size to completely cover the fifth wheel. If the kingpin plate is too narrow, the uncovered portion of the fifth wheel will collect dirt and foreign matter. This material may work into the fifth wheel locking mechanism, causing wear and occasionally difficult uncoupling. This material can also cause galling of the fifth wheel and/or kingpin plate.
If the trailer kingpin plate is not fully reinforced, distortion can result causing:
• Non-uniform loading
• Variation in kingpin length
• Cutting and galling of the fifth wheel or kingpin plate
If the trailer kingpin plate is distorted enough to cause any of the conditions listed above, we recommend that a new plate be installed.
The trailer kingpin plate must be properly greased.
Fontaine Fifth Wheels are designed and manufactured for use with all trailer kingpins that conform to SAE specifications, SAE J700, February 1993 and subject to the wear limits of SAE J2228, June 1993. These specifications cover SAE 2" kingpins only.
The SAE standard kingpin can be checked using the dimensions given at right.
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