Fifth wheel manufacturer Fontaine International recommends that fleets take special precautions during cold weather to ensure that their trucks’ fifth wheels continue to operate properly. Most fleets are already aware that many lubricants become thick and binding in low temperatures, and ice and sludge can build up on the underside of fifth wheel plates. As a result, parts may get stuck or move sluggishly, making operation difficult. The jaw and wedge may even be prevented from closing properly.

In preparation for winter, thoroughly clean the fifth wheel latching mechanism using a suitable cleaner or degreaser to ensure that all parts travel freely. Grease and road grime also should be removed from the slider mechanism of fifth wheels equipped with sliders. If temperatures are already consistently below freezing and the fifth wheel has a large buildup of grease and grime, perform a complete steam cleaning.

Once the fifth wheel is clean, it should be thoroughly lubricated. Grease the jaw and wedge on the top and bottom. Separate the jaw and wedge with a large screwdriver and distribute the grease along the full length of the mating surfaces. Open and close the fifth wheel several times to further distribute the grease.

Apply a moly-based lubricant for cold weather. Equipment driven in regions with extreme or prolonged freezing temperatures may benefit from lubrication with a less viscous substance to help ensure the proper movement of the latching mechanism. Fleets may wish to contact the lubricant manufacturer for guidelines on the mixing compatibility of any lubricant.