Lets face it, Rust sucks. It will destroy paint, seize parts and (if left untreated) eventually eat holes right through your frame. Once that happens, it’s a one-way ticket to the junkyard. Here are the easy methods I use “stop” rust and prevent new rust from forming.
How to Stop Rust on a Truck Frame
- First remove any loose rust with a wire brush or scraper
- Use a water based cleaning product to clean the surface of any dust, oils or grease
- Ensure the surface is dry to the touch
- Apply a rust converter with a paint brush or foam roller directly over the rusted metal at a thickness of 8.0 mils
- Allow to dry for 24 hours
- Paint the surface to protect against future corrosion (optional)
That’s all there is to it. No grinding down surfaces to bare metal or handling harsh acids. Simply prep the surface by removing any loose rust, clean the surface from contaminants and then paint on the rust converter to chemically treat the rust.
Since the product I use also doubles as a metal primer you can apply a top coat of paint directly over the surface if you wanted to.
What is the best rust converter to use on truck frames?
Corroseal actually chemically treats the rust by converting it to an inert (stable) compound. This will act to “kill” the rust and prevent new rust from forming.
Even though this stuff has been around for over two decades it can be nearly impossible to find in stores. Here is a direct link to buy Corroseal rust converter metal primer on Amazon. They had the best price around and the product arrived in good condition within only a few days.
Here is a great product video showing application on a rusty car rim:
Corroseal Rust Converter applied on truck frame (preparation, application & results)
As we move into Fall here in the Northeast, now is the perfect time to take care of vehicle maintenance. With Winter coming I like to make sure things like brakes, oil changes and any rust protection is handled now. Freezing weather and snow are not ideal conditions for this type of work…especially if you are working outside.
DIY Rust Protection
This is even more important when talking about rust protection. If you are going to do this yourself, you want this stuff on and dried before the salt hits the roads.
In the next few sections I will go over my process of applying Corroseal on my Toyota Tacoma pickup truck frame. The truck about 6yrs old with around 60k miles. It is still in pretty good shape but there are areas where rust is starting to develop. I would rather do a little preventive maintenance now then deal with a bigger problem down the road.
There will also be a few photos of the results, which so far I am very happy with!
Surface preparation
The bottle says that before application you should remove any loose or flaking rust and clean the surface from contaminants. To help with the flaking rust I decided to use a metal wire wheel brush attached to the end of a battery powered drill. Remember the whole purpose of this is “easy method”. However, If you don’t have a drill a simple wire brush should do just fine to remove the loose stuff.
Tip: Wear a respirator and eye protection! Small pieces of rust went everywhereeee.
The below photo is the steel wheel cup attachment on the drill and the smooth surface after a quick pass. This was a quick and easy to way to break off loose rust but it did leave behind some scratches. Next time, I would use a less abrasive attachment like a synthetic paint stripper wheel.
All loose paint/rust removed after a quick pass. Remember, we are not trying to grind down to bare metal. Just remove the loose stuff.
Next step was to clean off the surface with a hose and wipe it down. No extra cleaners were used as I wanted to make this as quick and simple as possible.
Application (using a paintbrush)
Now that the surface is cleaned up we are ready to start applying the Corroseal. According to the bottle there are a few different ways this can be applied.
Application Options:
• Brush
• Foam Roller
• Sprayer
To keep it easy I just filled up a plastic cup with a small amount of the solution and used a cheap paintbrush to slop it on. The stuff is pretty thin (milky) and a little went a long ways.
Here is a shot to give you an idea:
Application was easy and there was almost no mess at all Even though it is pretty thin, it sticks just good enough so there were no drips.
The instructions call for a thickness of 8 mils but I just slopped it on like a good coat of paint. According to the instructions activation begins immediately and rust should turn Black in about 10 minutes. If the area is Grayish then you need to apply more product.
So how did it work? See the results below.
Results
Photos of the frame from the next day. The Corroseal turned all the rust patches to dark black and so far I am very happy with the results! For the small amount of time and effort I am pretty impressed with how nice it came out.
This is also a “rust primer” which means you can paint the surface for an even better finish. If do you choose to paint, the instructions recommend doing so within 30 days.
In my case. I’m going to leave it just how it is and see how it holds up over the winter. I will also be applying Fluid Film before the winter to act as a barrier against the salt water (more on Fluid FIlm rust prevention below).
Here is another close up shot where the rust was forming on the under-rail. Even without paint this is more than acceptable for my daily driver. 
Now that the frame is coated and looking much better. The next test will be to see how well this does to stop the rust from coming back.
Some people just take a can of spray paint and coat the under-body without doing a rust converter and the rust is usually back within a couple weeks. This treatment should provide better protection vs “covering up” the problem with paint.
What causes metal to rust?
Rust occurs when bare iron is exposed to the moisture in the air. The mixture of oxygen and water begin the chemical reaction of oxidation where the iron loses electrons to the oxygen atoms. Over time this will weaken the bonds of the iron causing it to break down.
What makes this problem even worse? Salt
Salt acts as an accelerate to this processes by allowing the electrons to flow faster. Anyone who lives in an area where salt is used on the roads knows just how damaging this can be to a vehicles undercarriage.
They key here is “exposed metal”. If the metal is properly protected with a paint or coating it should in theory prevent the water and oxygen from reaching the iron to start the oxidation process.
Big problems for Toyota
If you remember. Toyota had a huge problem due to improperly coated frames on their Tacoma’s 2005-2010, Sequoias 2005-2008 and Tundras 2007-2008. This resulted in a massive settlement –estimated around $3.4 billion– where they had to replace truck frames at their expense.
Prevention, Tips to Prevent Frame Rust on your Truck
Remember, rust never sleeps and preventing rust from starting is key.
If purchasing a new vehicle and you live in an area prone to rust, it may be a good idea to look into undercoating. The undercoating will act as an additional barrier to prevent oxygen and water from reaching the metal.
There are plenty of places that offer this type of service or you can try buying undercoating in a can.
Fluid Film Rust Inhibitor
For a less expensive, less messy alternative to undercoating. Check out Fluid Film. Available in spray cans you can quickly apply it to rust prone areas and it also works great as a leather conditioner (see “Fluid Film on Leather Boots” article).
Fluid Film is what I have been using for a few years as rust preventive on my Toyota Tacoma. What I like about this product is that it is very easy to use, doesn’t make a mess and is relatively in-expensive.
Here is a direct link to buy Fluid Film on Amazon. I have also found this stuff at some auto parts stores but it was considerably more expensive.
I spray it on the undercarriage, gas cap cover, leaf springs, shock towers, bumpers etc. Oh, and don’t forget the tow hitch. This stuff lasts a long time and will prevent your trailer ball hitch from seizing if left in year round.
Conclusion, Final Thoughts
What I like about this product is the minimal amount of prep work required and the “paint-it-on” style application. I have seen other methods where you have to grind down to bare metal, mix up a bunch of expensive products and wait around for days while it all cures. That might be great for a show car but it is just not practical for a daily driver.
Last photo, taken 1 day after application. No paint applied.
Again, as I mentioned before this stuff can be vary hard to find in-stores. If you want to pick up some my recommendation would be to just buy it online. Here is a direct link to buy Corroseal rust converter metal primer on Amazon.
Stop back soon as I will post photos showing how well the Corroseal + Fluid Film combination did over winter. If you have any questions please leave them down in the comments and I would be happy to answer them.
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How did this hold up over the winter ?
Overall it did a pretty good job considering how easy it is to apply. I have since used this stuff on numerous other projects (lawnmower deck, wood splitter, & ball-hitch) all with good results.
However, on areas where road salt/sand is flung-up (underside of frame behind the tires) I did notice rust starting to reappear. My guess is… As the salt/sand is kicked up from the road all winter, it eventually wore through the Corroseal treated surface. On future applications I will give it 1-2 coats of paint once the Corroseal dries to offer better protection.
I took some photos and will post a Part-2 Follow up. Thanks for checking out the article!
Thanks for the writeup! Great tips. I am currently using this method now, but using Rustoleum rust dissolver. It’s a lot thinner and washes off every time it rains 🙁 but does a pretty good job if it can dry. Maybe I’ll try this Corroseal next time.
Thanks for stopping by. The Corroseal does not wash off as it designed to “neutralize” the rust, converting it to a black primed surface.
My only recommendation would be to apply a coat of paint ontop of the Corroseal for added protection in areas where the tires fling up road debris.
As winter approaches…yet again. I will be touching up a few areas and then spray some Fluid Film to prevent new corrosion. Overall I am very happy with this Corroseal/Fluid Film combo due to how easy both are to apply.
Before reading this I was thinking about putting liquid bed liner on my frame to have added protection from rust. I would think using the Corroseal first, then applying the fluid film, followed by bed liner paint would really help prevent salt and cinders from causing new rust spots to appear for at least a little while.
Here is an updated image taken this fall after applying the Fluid Film before winter.
I would be careful with the bed-liner stuff as the salt/water can get trapped behind the coating, causing even worse problems.
As you can see from the image, the Corroseal has “neutralized” and turned any previous rust Black, then the Fluid Film acts as a barrier to prevent/minimize new rust from starting. Also, I find it very unlikely any type of coating or paint would adhere directly ontop of the FF as the FF remains as a tacky liquid once applied.
Thanks for stopping by and keep up the good fight against rust!
I use Corroseal on big ships in salt water. For best results follow the directions and apply paint over it. If you don’t the rust will reform after a few months, and you need to re-treat it again.
Thanks for sharing. So far I have seen really good results when using the Corroseal and then coating with Fluid Film ontop. However, I will reassess after this winter as paint would help out in areas where the tires fling up road salt/sand. This is already my second winter using this method and I have been pretty happy otherwise.
I ordered this to use on my truck frame. Were you able to get to every part of the frame without taking anything off?
No, mainly I used this on the bottom of the frame, rear diff and any other easily accessible areas. It is fairly easy to apply with a brush but it would be hard to coat the entire frame without really stripping it down. All of the other areas were sprayed with Fluid Film for protection.
How much did you need? 1 gallon or 1qt of the Corroseal?
I purchased a quart and was able to do everything I needed with some to spare. Even with touch-ups and other projects I still have some left over, (a little goes a long way).