Rust Repair Recommendations

Bedliners will promote rusting but the stock rear wheel well liners will allow sand/rocks to be thrown up and will accumulate in the bed frame work.

 

Slowly putting together a plan to repair my bed floor rust. Picked up a rust free but rolled 2015 bed so that I have spare cross member sections as well as bed floor sections with the proper stamped ridge pattern for easy welding. This should be fun.

 

Updating my saga as I make progress. I'll probably put this together as a DIY post on my website once complete.

Front two bubbles got demolished into big holes today. Plus a few extra man made holes to clean up. The right side I question the integrity of the bed side-bed floor seam and kept checking further towards the cab but will inspect further once lifted off. Overall it's much worse than I thought, and the rear cross member only looks worse Gulp. Silver lining 4/6 bed bolts I exposed so far came loose easily.

 

When you see "just some small areas bubbling up under the bed liner" this may really be what's lurking.


The rear was much worse than the front and the drivers side worse than passenger side. Got all 8 bed bolts loose! Time to pull the bed off and start drilling spot welds to make one good bed out of two.


Here's what came off.

 

Did it rust from top or bottom? I crouch under the truck and pressure wash and spray everything suspicious twice a year.

 

They all rust up from the bottom. Mainly in the four areas where two of the major cross members are seam sealed to the bed floor. I speculate that these areas are flat on flat metal but not constrained enough to each other so they have small relative movement, wearing away and primer coating they may have had. The foamy seam sealer that doesn't fully seal the panels together either allows and traps in moisture and road salts. Then by the time you notice it from either side its eaten through both and into surrounding metal.

These 4 seam sealed areas that look like darker black. Will post better pictures once I get back down to where the donor bed is stored.

 

Yeah, this is what I saw on my 2019 last time I was there (developing first signs of rust). Sprayed with a cavity wax (Noxudol 700), it will slow it down severely.

Rust maintenance twice a year is must on this truck...

 

Your 19 already started bubbling under the Line-x, or did you see it start rusting from underneath?

 

I believe I paid for Rhino. No, it started rusting from underneath. Also when I damaged the liner in a few spots and peeled it along with the paint, it was all rust free.

Out of curiosity, I once measured a thickness of the salt deposited on my Tundra in winter in Massachusetts. It was 1/16" to 1/8". Ouch.

 

MA. is definitely brutal when it comes to salt, I plan on getting under the truck this weekend to give it a good flush and another coat of Amsoil HD before the bad weather sets in. Today was absolutely gorgeous, but we all know how fast that changes around here.

 

Decided it would be best to just take the entire cross member sections instead of mess around drilling spot welds and piecing cross member sections back together. Got one completely welded in, second one cut and cleaned up for final fitting.


Butchered up donor bed

 

Cutting wheel + welder make magic

 

Finished welding in the second panel. Lots of cleaning, chassis saver paint on underside, seam sealer everywhere. The factory seam sealer is terrible and completely next to the joint in many cases. It did change between 2007 and 2015 beds, it got thinner but still just as poorly aimed. Top side got self etching primer. It will need a lot of prep work yet before raptor liner.



I'm still not done yet. While this would buy me some time, this still doesn't prevent the problem from happening again. The design issue of the flat bed floor trapping an air space and road debris over those particular sections of subframe still exists. Debating next steps but I think they will include weep holes and cavity wax.

Bed went on and drove the truck home! Just need to reinstall fender liners and backup lights. For any amateur thinking of doing this, we have about 60 man hours into the job so far so 100% not worth it unless you're doing it yourself for "fun" and have good friends.

 

Stock wheel well liners are the main cause of the rusty beds.

 

Yes I did notice the 2015 has a slightly better wheel well liner design but still not adequate coverage. They allow road spray to inundate these seam sealed areas (one in front and one behind each wheel well) and the ones behind the wheel well have an open area for junk to get in between the two panels, rusting from the inside out. Further support of your conclusion is that the 8 food bed has a third large cross member at the very front of the bed far away from wheel wells - it has same design and seam sealer, but not rusted. Someone posted a DIY for better shields on here, I'm definitely going to make a set.

Edit: oh it was you, thanks! https://www.tundras.com/threads/diy-wheel-well-liners.21418/

 

Got it all prepped and sealed every which way. Wrapping up with the raptor liner finish today. One coat definitely didnt cover my amateur body work, we'll go for 2. Spot the 2.5 gen addition?



That'll work for me!

 

I finally got around to putting together a little bit of a write-up on the bed floor rust issue. I talk about how bad mine was, what I believe causes it, how I chose to repair, and then how to prevent again. Could save the beds of some 2.5gen guys for sure! Give it a read and share!

https://frugalfill.com/2nd-gen-toyota-tundra-bed-floor-rust-repair/