How To Fix A Rusted Truck Frame

Fixing a rusted truck frame can be a costly process. Depending on the vehicle’s make and model, expenses can range from $2,000 to $3,000, and sometimes even more. The primary driver behind these high costs is the labor, as repairing a rusty frame can be incredibly time-consuming.

how to fix rusted truck frame

For those who may not have that type of disposable income, there is another option. If you’re willing to do the work yourself, you can repair a rusty truck frame for a small fraction of the cost. While it will require a great deal of time and elbow grease, it’s actually not all that complicated of a process. 

We put together a basic overview of how to fix your rusted truck frame and provided additional insights on preventing rust in the future. Let’s break it down.

The Basics Of Rust Repair

There are a few simple steps to follow when you are removing rust from your truck frame. Bear in mind; these are basic overviews of the process. In some instances, there will be unique issues or specific circumstances requiring a professional’s expertise. In these instances, you will need to take your truck to a certified auto body repair shop and have them perform the repair. 

But in many instances, the task can be completed by following these steps.

Expose The Frame

Fixing your rusted truck frame starts by exposing the entire frame in order for it to be accessed. Begin by lifting your truck on a jack, so the frame drops down. Next, remove any parts that are obstructing your access. You’ll have to take off any wheel well covers, mud flaps, steps, and other trim pieces that conceal the frame.

Use A Wire Brush Wheel To Remove The Rust

Once you have exposed the frame, you can now begin addressing the rust itself. Use a drill and a wire brush wheel to remove the loose rust. During this part of the process, you will need to wear a mask and goggles, as there will be rust particles flying everywhere.

Thoroughly remove all the exposed rust, ensuring that you have given yourself access to address any affected areas on the frame. The wire brush wheel will remove most of the rust, but there will inevitably be some spots leftover that are too stubborn for a brush. For those, you’ll want to follow up with 80-grit sandpaper until the rust is completely removed. Following this step, you’ll want to use some 400-grit sandpaper to smooth the surface back out.

Wash The Frame

Next, you’ll need to wash your frame to make sure the rust has been completely removed. You can use household products like soap and water to do this, as no heavy cleaners or detergents are necessary. After washing the frame, make sure to rinse it off well and let the frame dry thoroughly.

Spot Treat

Once the frame is dry, it’s time to inspect the frame thoroughly. When it comes to rust, you want to make sure you didn’t miss any spots. If you discover any remaining rust, sand it off and spot clean that area in the same fashion listed above.

If the rust is severe to the point where it has eaten small holes into the frame, pack them loosely with wire mesh, then fill them with body filler and sand smooth. Once complete, wait for the body filler to dry.

Keep in mind that this is only safe to do for small holes. If there are large holes or cracks, the truck is not safe to drive, and body filler is not nearly strong enough to provide any added strength to the structure. If your frame is this severely damaged, you’ll need to have it welded or replaced entirely.

Apply Primer

After you have completed the above steps and spot cleaned any remaining rust areas, rewash the frame to remove any dust from the body filler, and wait for it to dry. 

Once dry, you can now apply the primer. You’re going to want to apply two coats, waiting for the first coat to dry before applying the second. After the second coat has dried, apply a clear coat to the entire frame, and after drying, reassemble your truck. Once you have put all of the pieces you removed from the truck to access the frame back in place, you’re all finished.

Can I Weld A Cracked Truck Frame?

The answer to this question is yes, it is possible to weld a cracked truck frame. However, this is not a job to be taken lightly. 

If you make a single mistake, you could endanger both yourself and your passengers. But more than just putting your safety at risk, you could potentially be doing something illegal.

Under federal law, holes cannot be drilled into a vehicle’s rail flanges by anyone other than the vehicle manufacturer. This means that many “homebrew” or DIY welds are technically illegal to operate on public roads. At the same time, you have the freedom to assess your own level of risk and use your truck for off-roading on your property, though we would advise against it. However, you cannot legally take that same vehicle on a public road or highway.

Furthermore, welders whose work is implicated in an accident can face civil liability for damages or injuries if the weld was not performed correctly. As a result, many shops will flat-out refuse to weld a vehicle’s frame, as they simply are not willing to take that risk.

Also, some insurance companies won’t insure a vehicle whose frame has been welded or cut. If you choose to have your frame welded, you’ll have far fewer options and likely end up paying a higher insurance premium.

That being said, a broken frame can indeed be welded by an expert who’s experienced with frame work. The process typically involves fabricating a plate or sleeve covering both halves of the break and welding both sides in place. Again, this is a task that should only be performed by a highly-skilled professional. 

Frame repair can cost as much as $10,000, so If your truck is worth less than this, having the frame repaired doesn’t really make a whole lot of sense in most situations. If there are frames available for your truck, it’s far better to buy a new one than to weld the old one. That said, for most classic trucks, a weld will be your only option.

Rust Prevention Basics

Once you’ve dealt with the nightmare of a rusty truck frame, you’ll never want to go through the headache again. Here are some tips to help keep your frame from rusting in the first place.

  • Avoid puddles when you’re driving: Puddles contain a lot more than just water, unfortunately. These small bodies of water can contain salt and other corrosive materials that splash on your frame over time. When possible, avoid driving through them, no matter how tempting (and fun) it may be.
  • Perform a thorough rust inspection at least once a year: It’s a lot easier to spot-clean and treat a few areas of rust rather than have to repair your entire frame. Anyone who has had to deal with it knows all too well that rust leads to more rust. By nipping these small spots in the bud, you’ll prevent them from turning into deep pits or holes in the future.
  • Always wash your truck after driving on salted surfaces: If you travel through an area where they salt the roads, or perhaps you live near the ocean, you are going to need to wash your truck every few days year-round. When there is salt on the road (or in the air), your truck is constantly exposed to these elements. Cleaning your truck keeps these corrosive materials from building up on your truck frame and eventually turning to rust. 
  • Apply an undercoating every few years: Applying an undercoat every few years makes your truck literally impervious to rust. Many manufacturers do so before the truck ever leaves the factory. But over time, these undercoatings wear down, typically within a few years. Keeping a fresh undercoat on your truck is quite possibly the best rust prevention method you can undertake.