Complete Corrosion Protection for my New T4R
 

I purchased a new 2021 T4R SR5 Premium this past spring. I've lived in the heart of the rust belt (south shore of Lake Ontario) for my entire life, so I know a little bit about corrosion and corrosion protection. I also came out of a 2014 Tacoma TRD Sport, so I know what rusts and what doesn't on similar vehicles. Finally, I used to work at a local Toyota dealership in Service, so I got to see what my friends swore at and what they'd do differently if they were building vehicles.

Seeing that this will probably be one of the last new vehicles I'll ever buy, I want it to last. My son is a former Toyota / Lexus Certified Service Technician, so all maintenance is done by somebody who really knows what he's doing. That left corrosion protection for the upcoming winter as one of the last loose ends I needed to tie up. I thought I'd share what I did and why with my friends here so that maybe some of you can consider the same steps. I'm also wide open to suggestions for further ideas.

The first thing I did was get the insides of my frame coated with the same product that Toyota uses on their latest program to keep Tacoma frames from rotting out from the inside. The coating also comes with a number of plastic plugs to close a number of holes stamped into the frame rails. Don't ask me how I got this done or how much it cost, but trust me, it's worth a bundle.

Second, I got the entire underside of the truck coated with a product called Waxoyl. I've looked at, read about and tried a number of different underbody coatings and I really liked what I saw in this particular product. I also asked them to coat the entire rear axle housing since they are known to rust through over time believe it or not. I also had them coat the trailer hitch. And yes, the spare tire was out when they did the coating. In case you're wondering, I would absolutely not - under any circumstances - recommend Ziebart undercoating or inner body coatings. The product and the process suck and the "free annual resprays" are just and excuse to get you in the door to twist you arm for additional products and services.

Third, I got all of the inner body areas sprayed with a product called Krown. This is an oil based product and I really like the fact that it seeps into small areas and seams to protect them. I didn't get it done on the underside because it does tend to wash off and needs to be re-applied at least yearly down there.

Next, I removed the plastic trim above the rocker panels on all four doors. This area - especially on the driver's door - is known to rust out because the underside of the plastic trim piece rubs through the paint right where you can't see it - until it's too late. I cut pieces of Clear Bra with radiused corners and applied them so that they covered an area just slightly greater then the trim piece. This should keep the plastic from cutting through the paint.

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Underneath the truck, I applied a liberal coat of Fluid Film to the Transmission Shifter Position Sensor on the passenger side of the transmission case. These are known to corrode and cause hard shifting over time. They can also be a bit of a bear to get off once rusted.

Under the hood on the driver side, I applied a liberal amount of Fluid Film to the Intermediate Steering Shaft. This is the part of the steering shaft with the universal joints and rag joint. For reasons that elude me, Toyota doesn't put any kind of finish at all on the bare metal. When this bad boy starts to corrode and bind up, it will feel like your steering is going loose-tight-loose-tight as you rotate the steering wheel.

Since I was under the front end, I slathered Fluid Film all over the metal power steering lines leading to and from the steering rack. Someday when either the lines or the steering rack need replacement, somebody's going to thank me.

I also coated the entire inside of the Lower Core Support as well as the foam gasket on the front of it that is known to trap both salt and moisture with a decent amount of Marine Fogging Oil. While I was in the area, I also flowed it into the area between the radiator and the core support of the same reason. Marine Fogging Oil is a special oil loaded with corrosion inhibitors for those of you that haven't heard of it.

While I had the Fluid Film in hand, I applied a liberal amount to the front hood latch mechanism as well as the rear hatch latch mechanism. I also laid a nice coat on the striker plate at the base of the rear hatch.

Finally, maybe the most important thing. My son and I removed all four Alignment Cam Bolts from the Lower Control Arms. These are known to trap salt and moisture that allows them to corrode pretty quickly. When that happens, your ability to use them to align your truck goes pretty much out the window. So, we removed them and liberally coated them with Never Seize. As the pictures below show, even though the truck is only 8 months old, they were already starting to corrode. Even though we carefully marked the positions of the cams, the truck goes in for an alignment tomorrow just to make sure.

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Did I forget something? Probably, but this is the best corrosion protection program I've ever applied to any of the numerous vehicles I've owned over the years.

The only other thing needed to get the truck ready for snow is slapping on the winter wheels and tires. I scored a nice set of 2019 Tacoma TRD Sport 17" wheels with TPMS sensors on Craigslist and mounted a slightly narrower than stock set of Blizzak DM-V2 Ice and Snow tires on them. My experience has shown that narrower tires are always better on hard packed snow and ice. These will go on in early December.

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I hope this rather lengthy post will help some of you that also want to prevent your T4R's from rusting into an early grave.

Hi and great work on your 4r! You may also consider removing all 3 of your skid plates and spraying what they hide above them. Also, there's a small cover panel about 1/2 way on the left frame rail (below where the driver's door and rear door meet). It covers a small proportioning block and those flare nuts rust out quick. It's 2 10mm bolts. I had my guys also spray my driveline bolts and exhaust bolts. If you can get help from your son, remove bolts and coat them with anti-seize/oil. Same for the oxygen sensors. Makes them easier to remove when time comes to replace things. Also spray the spare tire mechanism, chain and bracket. Make sure the 2 breathers at the rear axle are clear and/or re-locate them. You can also replace the non-torque sensitive zinc bolts with stainless flange bolts. Krown and Rust Check are basically the same formulas. They started out as 1 company, but the owners had a disagreement and split into 2 companies.

Thank you for the great suggestions. Truth be told, I had the front skid plate removed when they did the Waxoyl treatment and they did it on the ground. The spare tire mechanism was also done with Fluid Film when I removed the spare for the Waxoyl treatment. I will pull that small cover plate on the driver side frame and FF those fittings though.

I also forgot to mention that I apply a thin layer of Never Seize to the center bore of each wheel prior to winter to prevent the wheels from seizing to the hubs.

I really like the idea of clear bra on the rocker panels. unfortunately with rust we cannot prevent it, only delay it. every vehicle with steel components will rust, some sooner than others. for every person that says they had a make/model that rusted out too quickly, someone says the exact opposite. especially with the road salt - I'm sure in NY it's used almost as heavily up as up here but you have seemed to cover many bases with what you've done

taking care of stone chips early is also helpful + a regular wash and wax routine to protect the finish

I just got done spraying black cosmoline everywhere I could. Removed skids and spare tire. Cleaned and prepped and sprayed the complete underside, inside frame rails and inside doors. I had used fluid film before on other vehicle, but like the cosmo better. Dries to a nice waxy film.

Good luck. Im outside of Rochester too now. Certainly done a thorough job and the best you can. Hit the major points from my perspective - was gonna add in the spare wheel winch - but you noted that. The hinge on the gas tank door has rusted out on me too - so hit that regularly

Yeah, I’m asking. How much?

Probaby cheaper just to move to California. :D

I am sworn to secrecy.

What I would suggest for anybody wanting to really protect their frame is that they make sure whatever product is used gets liberally sprayed inside the box sections. Classic "undercoating" only covers the exterior surface. Even if somebody says they're going to do it, I'd recommend checking to insure it was actually done. By the time corrosion that starts inside the box sections becomes visible, it's way too late to do anything about it.

Weak. :rolleyes:

Thanks for this and pointing out the weak spots. Just took delivery of a 2022 TRD ORP. I also plan to keep it for a long time. Have been rustproofing my cars with Krown for years and it's a good product. But like anything else it's only as good as it's application. Pretty much drove it straight from the dealership to Krown requesting special attention to fogging the inside of the frame. They obliged as they were happy I had pulled the skid plates and spare beforehand. This was after battling the dealership over why their electronic rust gizmo was utter garbage. So a few questions. Have been hand spraying the frame afterwards through the holes as best I can noticed many holes in the frame. You mentioned plugs for some holes can you narrow down which holes? Also noticed the foam strip at the bottom of the rad thinking of pulling it right out talk about a salt sponge. Guessing its there only to max air flow. After marking and pulling out the cam bolts and having it realigned do you feel you altered the alignment? I'd like to do this also but thinking of using marine waterproof grease on the cam bolts. Salt sucks.

I had to laugh at the part where you said the dealer tried to sell you the electronic rust prevention system. Yes, they are 100% complete and total garbage. Back in college in an electrical class, we decided to see if we could calculate how much voltage would be required to make one of those work based on an educated guess on the surface area of an average vehicle. Yes, it could work, but you'd need an extension cord to get to a 110v outlet!

Let me try to answer your questions. First, the holes they plugged were only the ones that the Tacoma frame kit had plugs that would fit a 4Runner.

I decided not to pull the foam strip since I wasn't exactly sure what it was in there for. Trust me, if the didn't need it for something, it wouldn't be there.

Finally, on the alignment cam bolts, we used Never Seize, but Waterproof Marine Bearing Grease was another very viable alternative. Anything that inhibits corrosion would be better than the plating that Toyota uses.

As for altering the alignment, we marked the position of everything, but if you've ever had a vehicle on an alignment rack, you'll know just how little movement can mess with proper alignment. The truck goes in tomorrow for an alignment and I'll see how far off - if at all - we were. The steering wheel is still straight and it drives perfectly though. I just don't want to take a chance and ruin the new Blizzaks.

Thanks for the info. Yah I laughed at the dealer over the gizmo. Been an auto mechanic for 40 years. Seen them rusted off the fender they were mounted on and still blinking like it was working. They were unimpressed with my comments and their response was to tell me it could void my warranty if I had it coated. I'll take that chance thanks. It's just a money maker for the dealer. Doesn't sound like the alignment changed one bit that's good news. You should get a before and after readings would love to know the readings. As for the plugs that's interesting did Toyota decide some of the holes were problematic? As for the foam it's gone on my end.