Except for automobile enthusiasts and hobbyists, most people don’t give much thought to their car’s rocker panels, even though they step over them every time they get in and out of the vehicle. What is a rocker panel, anyway? And what purpose do they serve on your car or truck?
On standard cars and trucks, there are two parts of the frame that connect the front and rear parts of the vehicle: the roof supports on top, above the windows, and the rocker panels down below, spanning from the front wheel well to the back wheel well.
These days, rocker panels play a very important role in vehicle structure and safety, so when this part of the car gets damaged, it needs to be taken very seriously. Almost all cases of rocker panel damage are due to the metal rusting from the inside. Because of where they are located on the vehicle, they are exposed to lots of moisture and other substances, such as the salt used to de-ice roadways, that make them prone to rust. In off-road vehicles, rocker panels can also be dented or broken by rough terrain; it’s only a matter of time before that sort of damage turns into a serious rust problem.
The best way to approach rocker panel repair will vary depending on the type of car or truck you have. Essentially, it all boils down to whether your vehicle relies on these parts for critical structural support.
Rocker panel repair for structural damage
Most drivers who are looking at a case of rocker panel damage will fall into this category. This is because the majority of cars made today have a unibody construction, meaning the frame and the body are a single piece. Unibody automobiles rely on the strength and rigidity of the rocker panels to keep the whole thing from sagging in the middle.
Many cars with modern crash safety features also depend on strong, undamaged rocker panels to keep the vehicle cabin from deforming while the front and rear crumple zones absorb the impact of an accident.
Finally, even modern trucks built with a body-on-frame construction (i.e. not unibody) use rocker panels to reinforce the structure of the vehicle.
All this to say that, structural damage to rocker panels is a very serious problem, and the rocker panel repair needs to be done properly to ensure the safety of you, your passengers and everyone on the road. A quick fix, band-aid solution is not an option here.
Rocker panel repair or replacement?
In the case of structural damage, the only suitable rocker panel repair involves removing all of the rusted or compromised metal, often the entire rocker panel, and welding a new one in its place. This is inconvenient for a few reasons, not the least of which being that very few people are experienced enough in sheet metal welding to do this themselves. A rocker panel repair that requires welding will need to be done by a professional.
But that isn’t the only problem with welding in a new rocker panel. The fact is, welding seams that are not properly sealed and protected are extremely vulnerable to rust, so a poorly done rocker panel repair can have you back at square one before you know it. For this reason, it is vitally important to seek out an experienced, high-quality professional for this repair.
Given the inconveniences that come with a welding repair, and the fact that welding is the only way to safely repair a structural rocker panel, there are some who recommend not repairing it at all—from their point of view, it simply makes more sense to replace the vehicle rather than dealing with the hassles of a rocker panel repair that could be a ticking time bomb.
This is not a possibility for everyone, of course. If you’re on a tight budget or have a car that is collectible or of special importance to you, a welded rocker panel repair is the only option. Make sure it gets done the right way!
Non-structural rocker panel repairs
Some owners of classic cars with a body-on-frame construction may be able to repair a damaged rocker panel without the need for welding. If you can verify that your vehicle’s rocker panels are not critical structural elements, then a less invasive repair may be possible.
This is the basic procedure for repairing non-structural rocker panel damage:
- Remove all of the rusted metal, and keep in mind that what you see on the outside is just the tip of the iceberg. Just scrape it all away!
- Rough sand a couple inches of the undamaged metal around the rusted part.
- Fill inside holes and cover any exposed metal with a special automotive anti-rust paint.
- Depending on the extent of the damage, you may need to apply strips of fiberglass matting soaked in anti-rust paint to rebuild the original shape of the rocker panel.
- After the repair has dried (usually overnight), apply protective coatings, such as waterproof filler and anti-chip coat, sanding in between coats.
Remember: this type of repair is only appropriate for cars where the rocker panels are not structurally important.
Obviously, the success of this rocker panel repair will depend on the quality and suitability of the products used, as well as your technique in applying them. When in doubt, ask a trusted automotive professional!