When was the last time you purchased a car with hub caps? Unless youre driving a vintage automobile (like some of mine), its probably been a while. All car manufacturers now put much more creativity into the design of their factory wheels. In the past, wheels were usually made out of stamped steel and attached to the car with four or five lug nuts. This design, although functional, didnt present a very attractive picture. Hub caps were used to hide the wheel and its attaching hardware, the lug nuts and studs.
Today, car manufacturers have a much more attractive selection of wheels to choose from. What they all have in common is an exposed lug nut which isnt hidden by a hub cap. In order to dress up these exposed lug nuts, they are typically covered with a chrome-plated cap to make them look nice and shiny instead of rusty and ugly.
The problem is that moisture gets in between the lug nut and the cap and the nut begins to rust and swell. That corrosion then pushes on the chrome nut cover, causing it to become enlarged. Now, when a technician tries to remove the wheel from the vehicle, he is forced to use a socket one size larger than normal because the proper socket will no longer fit. Over time, the lug nuts will continue to swell to a point where they are so misshapen that they will not accept any socket. While this isnt necessarily a safety issue, in that your wheels are not going to fall off, it can be an issue when the lug wrench that came with your spare tire will no longer fit.
Unfortunately, this is a problem we see far too often, and its not limited to only Ford vehicles or to any other specific manufacturers. It also has no correlation to the process of removing and installing lug nuts with power tools. We have seen lug nuts swell on neglected wheels that have never even been removed. At this time, all of the OEM replacement lug nuts are manufactured the same way, which means that it is certainly possible that the problem could reoccur over time, even after replacement, if OEM lug nuts are used. Our research has uncovered an aftermarket alternative which is a one-piece design lug nut which has been chrome plated and is available to fit most applications. This eliminates the possibility of moisture intrusion, corrosion, and the resultant swelling. We have also made a commitment to purchase these aftermarket lug nuts in bulk so that we can pass the savings forward at a more nominal cost.
So if your service advisor is recommending that we replace the lug nuts on your vehicle because theyre swollen, were not nuts. There truly is a real reason for it.