Now, I have very little experience with this sort of thing, so this was definitely a learning experience. But, part of the motivation of buying a fixer-upper truck was to learn how to do basic maintenance and repairs myself. Here’s what I did to fix rust holes in a truck bed, and here’s what I learned along the way, mistakes and all.
Materials and Plan
I decided that I wanted to keep it as simple as possible. Since I planned to cover the bed with a spray-on liner, I wasn’t worried about how the final patches looked. I just wanted a functional and inexpensive patch that would fill in the holes and stop the rust from getting worse.
The Bondo Rust Hole Repair Kit made the most sense. The holes ultimately weren’t big enough to justify buying a big container of body filler. Plus, a kit that contained all the odds and ends I’d need was perfect for a beginner.
I looked into a few different types of paint-on bed liners, since I really liked the look. I decided to go with the simple Rustoleum spray can ones, mainly because they were the cheapest option and didn’t involved any extra equipment to apply. I thought I could get by with three cans, but ended up needed four, so this was a little more expensive than I’d anticipated. But, I’m happy with how it turned out.
All of the materials, I picked up at either AutoZone or Harbor Freight, with the exception of the dremel, drill, and safety equipment, which we already had.
What you need to fix rust holes in a truck bed:
- Spray-On Bed Liner (4 cans) – $50
- Bondo Rust Hole Repair Kit – $22.99
- Self-adhesive Body Patches – $8.99
- Painter’s Tape – $6
- Loctite Naval Jelly Rust Remover – $5
- Cutting attachments for Dremel – $30
- Coarse Grit Drill Sanding Discs – $5
Things we already had:
- Safety Glasses
- N95 Mask
- Work Gloves
- Cleaning rags
- Paint Brush (to apply Naval Jelly)
The total cost ended up being roughly $130, although that included some cutting and sanding attachments that we’ll be able to use for other projects.
Steps to Fix a Rusty Truck Bed
1. Clean out the Bed
The first step, of course, was just cleaning out the bed. It was pretty grubby and dirty. I wanted to get as much of the dirt and rust out of it as I could so that I could work in there without worrying about needing a tetanus shot afterwards. This first entailed getting the camper topper off, and then spending some time hosing it down and waiting for it to dry.
2. Cut out the Rust
Before I could repair anything, I needed to get rid of the existing rust. I started with sanding off as much as I could. At one point tried to use a screwdriver as a chisel to chip away at the rust holes. That didn’t get me very far.
Eventually, I realized I was going to have to just cut out the rust holes (sometimes you have to make things worse to make them better). The thought of cutting through the truck bed was pretty intimidating, but it actually didn’t take much. Out little dremel and the set of attachments did the trick. The hardest part was just being extra careful that I only cut through the truck bed itself and didn’t damage anything underneath.
I also used some Loctite Naval Jelly Rust Remover. It’s a simple process of painting it on, waiting a few minutes, and washing it off. I stuffed some cardboard under the truck bed to stop any of the naval jelly from dripping onto the suspension.
3. Sand the Truck Bed
There was a good bit of surface rust on the bed that I wanted to sand off, but this step was more for the bed liner than for patching the rust holes. In order for the spray to adhere, the few spots of paint that were still in decent condition needed roughed up. I used a hand drill with a sanding attachment and just went to town on the entire bed. Pretty fun.
Once all the rust was cleared out, and the paint was sufficiently roughed up, I needed to give it one last good clean before patching the holes. This time, instead of hosing it off, I just wiped it all off with a rag and some soap and water, then went over it all with a little bit of ethyl alcohol to sterilize it.
4. Patch the Rust Holes
Time to mix up the Bondo and get the actual patches in place. The Bondo kit came with some mesh patches, but not enough to quite cover all of the rust holes, so I had to pick up a separate pack. I cut and adhered the mesh patches to provide some support for the Bondo mix while it dried.
Here is where I sort of went wrong. I didn’t really pay attention to the fact that the Bondo kit included two different types of filler. There was a “glass” filler that was supposed to go on first, and a “body” filler that was meant to be coated on top of it. I’m not really sure how much of a difference it would have made for this purpose, but still, I should have actually read the directions. Instead, I just used each type by itself.
I also didn’t realize that the filler was fluid enough to run right through the mesh patches while it was drying.
Luckily, I had left the cardboard stuffed between the truck bed and the suspension, so none of the body filler dripped down onto anything important. Still, it ended up wasting a lot of the filler, and doesn’t look great from underneath. If I were to do this again, I’d put some sort of temporary solid patch behind the mesh (I read about someone cutting up a soda can for a similar purpose). This would (hopefully) prevent the filler from dripping through while it was hardening, and then be easy to remove after everything was dry.
This ultimately ended up just being a cosmetic issue, but could have been worse if I had run out of body filler because it was dripping through, or if it had hardened on any important truck components beneath the bed.
5. Sand the Patches
The filler didn’t take too long to dry. Once it was hard, I sanded it down as much as I could. It didn’t look super smooth, and would have been impossible to match the truck bed exactly, but at least I got all of the rough edges off of it. Then, once again, I had to spend some time cleaning all the debris out of the bed. I was about to spray on the bed liner, and needed the bed as pristine as possible, so I spent a good bit of time cleaning the bed and making sure it was totally dry before the next step.
6. Prep with Painters Tape
Now that the bed was fully cleaned out and the patches were dry, it was time to prep the truck for the spray-on liner. I love the crisp lines that I ended up getting from the tape. Also, you might notice I was doing this in a car port, so I used large pieces of cardboard behind where I was spraying to protect my neighbor’s car.
7. Spray on Bed Liner
The bed liner was easy to spray on, and three cans got me through two full coats. It still looked a little thin and had a few spots I’d missed after two coats. I had to run out the next morning to buy another can for the final coat.
8. Admire the Final Results
Overall, I’m really happy with how it turned out. I should mention that the spray-on liner ended up not being very durable, and is already scratched up from throwing our mountain bikes in the back a couple of times. Still, it looks a million times better than it did at the start, and the rust hole patches have held for four months so far.
Hopefully this is helpful to anyone trying to fix rust holes in their truck bed. I’d love to hear if you’ve tried something like this, and how it worked out. Let me know in the comments!