I read an interesting article on TruckingInfo.com about the myriad problems a trucker can have with something that is (on the surface, anyway) remarkably simple: wheel-ends. I’ll certainly be the first one to admit that I’m probably not the best person to be writing this article, as I’ve not got much in the way of vehicle maintenance experience myself, but I found it fascinating the number of seemingly insignificant details that have a large affect on a truck’s performance.
This excerpt from the article is a perfect example: Loose wheel bearings allow for poor alignment between the cone and the cup, which causes the hub to wiggle on the spindle. That allows the wheel to run off center – perhaps only by a tenth of a degree or so, depending on how loose the bearing is. “Any component that allows a tire and wheel assembly to wander off center or run any way other than vertically true will affect tire life,” stated Guy Walenga, of Bridgestone Tires, and I have no doubt that every aspect of a truck’s function can only benefit from such precision.
To raise an example, the trailer kingpin is a vital, sturdy, and seemingly (for lack of a better phrase) unimportant part of the junction between trailer and cab, but this could not be further from the truth. While the fifth wheel may have more moving parts, it is no more important in the prevention of accidents than a trailer kingpin.
To again paraphrase a well written point, “seeing the wheel end as a system rather than a collection of parts headed in the same direction can help troubleshoot some tire wear problems.” And in the case of the fifth-wheel assembly, this is certainly the case. Wear on a kingpin, whether due to weather, sand, insufficient oiling, or other factors, is inevitable, and often the first thoughts that come to mind when wear is found is a kingpin replacement.
While replacing the kingpin may solve the immediate problem, it may, in fact, cause more problems to the system itself. Whether it be from weakness in the plate the kingpin is re-welded to, or the fact that (due to portions of the crossbar/anchor sometimes needing removal as well) the anchor point for the kingpin is not quite as sturdy, a kingpin removal can sometimes cause seemingly unrelated difficulties.
As such, I urge you to consider repair of a worn kingpin, as opposed to replacement. Not only are refurbished kingpins as reliable as newly-manufactured kingpins, but the procedure used to perform the repairs does nothing to compromise the integrity of the system, and has been shown, in several cases, to better resist wear than new kingpins.