Did some rustproofing last weekend and wanted to share some pictures and advice. Full disclosure: I am by no means an expert, so use my advice at your own risk. I take no responsibility if you dick up your truck. :hippie:
I wanted to do this because where I live, winter road salt is a fact of life. It absolutely destroys the frame and underbody of most cars within a decade, regardless of make or model. With my family and I expecting to get at least 200k out of this vehicle without any major repairs, I want to make sure the beast actually gets there and doesn't have its life cut short by corrosion. Hence, the rustproofing.
Also a note on rustproofing products: I use
Amsoil Heavy Duty Metal Protector. I've only ever found it in spray cans, which look like this:
What I really like about this versus other products is that it forms a semi-permanent, super-tough, wax-like barrier against the elements (similar to cosmoline?). I avoid asphaltic or tar-based undercoatings because they tend to crack or fracture as time goes on, trapping water against the frame and exacerbating rust. Being a wax-like coating, AHDMP is still flexible and doesn't crack or fracture as easily as the undercoating goo most places will slather your truck with. It's also self-healing in my experience when cracking, fractures, or chips do happen. It's much better than the tar-like coatings that are out there, imo.
I also avoid oil-based undercoatings like
Fluid Film or
Krown for the majority of my rustproofing duties because I've found them to be ineffective where I live. They come off way too easily, especially Fluid Film. I've literally blown that off with a spray wand while rinsing off the salt post-snow storm. I also don't like that these hold dirt and other schmutz all over the frame. AHDMP doesn't blow off in a car wash or with a wand, and since it dries to a wax-like coating, doesn't hold dirt or grime. That said, I
do use Fluid Film with a
Kellsport Products extension wand to get into the frame itself, as AHDMP can't really get in there and protect the interior. Fluid Film is perfect for this role to boot because it's a very effective rust preventer
when it doesn't get washed off, which it doesn't inside of the frame as it's sheltered from the elements and car washes.
For those hesitant to use this, please feel free to do your own research or make your own decisions. All of the above is totally anecdotal and based off of personal experience/internet discussions. I can't prove any of it with the rigors of science, but I've found it to work for me. If you do want more proof, the closest I've found to a
head-to-head, scientific test on these DIY rustproofers can be found on the Ford Raptor Forums, starting with
page 7. You'll see in that thread that when exposed to the elements, AHDMP far outperforms all other products in the test, including Fluid Film. It's only when sheltered from the elements that Fluid Film excels. Also worth noting is that Mercedes-Benz has been
wax coating their G-class frames for decades, so there's precedent in the industry for this stuff (though I can't claim that these are similar products or processes).
ALRIGHT, NOW ON WITH THE SHOW!
Step 1: Lower your spare tire, remove it, and raise the tire chain a few inches off the ground. Leave the chain dangling so you can hit it with the rustproofing later on.
RTFM to find out how, because it's not intuitive.
Step 2: get your truck off the ground somehow, SAFELY! I recommend starting with the back of the vehicle if using a jack or ramps. Of the two, ramps are preferable as they won't be making contact with the frame. A jack or jack stands will cover up their point of contact, and this will mean that spot doesn't get rustproofed as you spray around.
Lifting the truck isn't mandatory, but will make the job a million times easier. I chose to use
Petersen Tru-Cut Ultra Ramps, the 9,000lb GVWR version. They're the only ramps I could find that were steel and had central structural supports/bracing. There are other steel ramps out there, but they lack this support, and there are plastic ramps out there too. I've seen steel ramps without central supports/bracing bend, and I've seen even the "12,000lb GVWR" plastic ramps crush under trucks that are only 4,500lbs. My life is worth the extra $15-50 the 9000lb steel ramps cost, and I think yours is too, so please use common sense when purchasing products like these. Also make sure to chock your wheels and use jack stands as redundancy! Note that my jack stands are short and wouldn't have done me much good, so I need to get bigger ones.
Step 3: remove your skid plates. If you started in the back, this means the gas tank skid. To do so, you'll need a socket wrench and a 12mm socket (no extender for this skid plate). Before you actually go for it, though, make sure to place something under the gas tank skid to hold it up as it is long, unwieldy, and will put some weird torque on the last few bolts you unscrew. It will also likely bonk you once you get it loose if you have nothing holding it up.
As you can tell, a shipping box didn't do the trick, but you get the point. I ended up using a floor jack, which I've seen people do here on T4R for installing aftermarket skids. Turns out, it works just as well in reverse.
There are a total of 6 bolts you'll need to undo: 4 on the driver side, 2 on the passenger side. The two on the passenger side are definitely the harder of the 6 to unscrew, and I'd highly, highly recommend first removing the one circled in the picture below.
It's not only the hardest bolt to remove in general as it's located behind the rear prop shaft...
...but it also receives a disproportionate amount of torque as you loosen the rest of the bolts. This makes it very hard to remove as more and more weight from the gas tank skid rests on this oddly-placed bolt.
Step 4: wash your frame! I used a bucket and a towel, but I've read of people using power washers and other methods too. Either way, the goal is to get rid of dirt, crust, and contaminants below so you don't trap them in with the rustproofing.
Kaiju was only 4 weeks old at this point, so there wasn't much to clean.
Step 5: spray! Despite this being a post about rustproofing, I'm actually going to skip giving much procedural advice here because, like I said, I'm not an expert and don't want to suggest something that will end up ruining your vehicle, but I do have a few tidbits:
- Wear clothes you don't mind throwing out. This stuff will drip all over them, and it will ruin them, not just with stains, but with a waxy residue that even 2-3 washes in the washing machine won't get out.
- Wear a respirator of some sort, and make sure you work in a well-ventilated area. You'll be doing this for at least a couple of hours, and inhaling a couple-of-hours-worth of this aerosol will screw you up.
- Also wear protective goggles of some sort.
- Do it during the daytime. I did this during the night, and even in a lit garage, it made it a lot harder. I went back under the next day to check on everything, and it was much easier to see everything.
- Put some cardboard down if you care about the surface you're working on. This stuff will stick and stain.
- Amsoil recommends not using this stuff to protect electrical connections and other areas with electronics. While most of the stuff under the 4Runner is obviously sealed against the elements, try not to get any AHDMP on anything electronic. You'll see a lot of it (trailer wiring harness pictured below).
- The frame near the wheels will be hard to spray from underneath as it raises up for the suspension/wheel wells. However, it's really easy to get to from the outside at the wheel wells themselves. Just try not to get any on the tires.
- I'm not going to say whether you should or shouldn't spray it on your exhaust system, but if you do, be prepared for months of bad smells. The AHDMP will survive through the heat.
- I'm also not going to say whether you should or shouldn't spray the underbody while you're working, but keep in mind that takes a lot of work and the main focus is the frame. Prepare to buy a lot of rustproofer if you want to do the underbody as well, because if you don't, you're going to be left high and dry halfway through this.
- Don't get any on the brake contact surfaces.
Step 6: reattach the gas tank skid. I didn't rustproof this as I will be replacing it in a year or two, but you can if you want. I
would recommend using anti-seize on the bolts before reinstalling to prevent future rust, though, and even spraying a bit of your rustproofer on the bolt heads once finished. Don't reinstall the spare tire here. Wait until the end for that.
Step 7: if you're using ramps and started with the rear, carefully bring the truck down, reset the ramps to the front, and bring the truck up again. Pro-tip: have a helper nearby to do the driving part of this for you, as you're going to be covered in this stuff and you don't want to get it on your interior; it
will stain and
will leave wax stuck in your seats for a long time. Pro-tip #2: put the truck in 4WD. It will make it easier to get on the ramps. Otherwise, the ramps just slide around.
To remove the engine skid plate in the front, please see
Antman's excellent tutorial on doing an oil change. The instructions for removing the engine skid are in there. (bonus: if you bought ramps for this job, you can also use them to easily change your oil and not worry about grinding away at the skid hooks for clearance as seen in that thread!)
To remove (what I believe is) the transmission skid, you'll need the same socket wrench and 12mm socket, but also an extender, as the front two bolts holding the transmission skid are recessed (circled below).
There are a total of 4 bolts here to remove, and unlike the gas tank and engine skid, you don't have to worry about this one bonking you once you get the last bolt out. It has a nice hook on it that will hold it up once everything's removed.
To get the transmission skid down as it hangs on this hook, push up on the skid and pull back (towards the rear). The hook should be free from its hole in the frame and come down after that.
Step 8: wash again!
Step 9: spray again!
Step 10: reattach the transmission and engine skids (in that order).
When doing this, keep in mind most of the holes for the skids are oblong to allow some flexibility in reattaching. I got all of the bolts loosely re-fastened first, and then did a final tightening ("tight is tight enough").
Step 11: get the truck off the ramps. Again, suggestion is to have someone else do it so you don't ruin your interior.
Step 12: reinstall the spare tire.
And that's it! Congratulations, you have now done your part to fight the evil that is road salt and corrosion. :biggrin2: Keep in mind that you'll likely need to do this once a year to maintain any corrosion resistance (preferably in the fall before snow starts) and that no "rustproofer" will actually make your truck rustproof. Washing after snowstorms and saltings will still be necessary if you want to truly take care of your baby.
Hope that helps everyone.
First real mods will be a Frontrunner rack and Budbuilt Bumpout Sliders.
