Rust under spray-in liner. What to do?

Hey guys, I've had my truck now for about 2 years and love it. Checked the records and the frame was inspected in 2010 before I got. It passed and was undercoated and looks to be in decent shape. It also came with a spray on bed liner that looks like it's been on there a while. I've just started to notice there is rust underneath by the right rear fender well bubbling up. You can see it from underneath as well and I could probably put my finger through it if I tried. I searched and could not really find a related fix. Any Ideas?

Pics:

 

yep, I would say that looks bad.

I see no fix beyond sanding off the undercoating, cutting out the bad sections and welding in new metal. plus how much more rust damage is under there in places you have not seen yet?

if it were me I would look for a replacement bed from salvage yards and just wait until you find a good one. what you have will last a while giving you time to find a nice replacement for it.

I say this because you can never stop rust once it gets into seams like that so a repair will nly last a couple of years then look the same as it does now but on each side of the repair you make. what you spend trying to repair your old bed every few years will likely cost as much if not more then buying another bed and be done with it. it all comes down to how long you plan to keep the truck, if that's just a few years then repair it but if you want to get another 5-10 years out of it look for a replacement bed.

 

I have the exact same spot in my truck as well under my spray in bed liner. No fix without removing some of the liner. I have line X brand spray in so i called them and they will repatch the bedliner for $40.00. Dont need a new bed, just cut and burn in some new metal. It is right on the pinch so i am going to recreate the pinch so it looks proper. I will take pictures of everything when i do mine. I need to do it before the snow flies and the salt spreaders are out.

 

I too have the same rusted out metal under line-x in the exact same spot. Wonder why

 

in most cases its because there was trapped water in the seam that was sealed in by the liner.

this is why I make sure to never get a bed liner sprayed in if it has rained within a day or two before. it takes a few days for trapped moisture in bed seams to dry out.

if your bed is sealed then there is no issue but sometimes it has small cracks in the caulking that lets water get into the seams.

its also a good idea to not spray the bottom at the same time so if there is moisture trapped it can "hopefully" dry thru the bottom of the seam so I will wait a week before getting the bottom sealed or undercoated after

 

I would agree 100% other than it seems to be strange that all have it in the exact same spot. Seems to much of a coincidence to me.

 

well the location is likely due to Toyota not putting as much body filler in that spot or they squish it all out when assembling, then again it could just be a common point that flexes breaking the caulking seal to allow water in.

no doubt it is like THE spot that always gets rusted first.

 

I would have to agree, my truck is 100% rust free excluding this spot so it must be the weak link. O well, ill update with pics when i fix it.

 

That's the same exact spot that rusted out in mine. I pulled out the drop-in and found some surface rust. Wire wheeled the rust out and could see the driveway

After cleaning everything, I welded in a patch only to burn through a previously unidentified rust spot. So, I cut that out, welded in another patch and...found another spot. Basically, the back half of the passenger side wheelwell had rust holes.

After patching things up the best I could, I hosed everything with rubberized undercoating and put the drop-in back. It's far from perfect right now but it's something I'll revisit next spring.

 

Yeah I plan on keeping the truck for a while. Was planning on a lift and some wheels and tires. Still have a bit to pay off though. It's frustrating running into this kind of stuff on something you're still making payments on. Hopefully I can work on a fix. My cousin has a welder but has no real experience. How difficult is it to weld in and fab up a new piece. What type of metal do you use?

 

most sheetmetal body repair I see is done with a torch and not a welder. the floors and sides are too thin a metal for welding. welding is used for thicker metals not sheetmetal work.

 

Any pics or tips for those who have done this before then? Like what type of metal you used and how you formed the wheel well section and the ribs in the bed?

 

My Brother-in-Law patched mine. First thing all the rust had to be ground out. The hole got around twice as large then.

To form the Ribs he used a "Brake"

http://www.industrialladder.com/productDetails.do?productID=4779&gclid=COXNhen9sMECFcRzMgodQycALQ

To form the sheet over the curve of the wheel well he used a small hammer to form the sheet metal to fit.

$65 Malco SH3 18 oz. Setting Hammer, 1 Pack

http://www.amazon.com/Malco-SH3-Leather-Gripped-Hammer/dp/B001QTMZYS

He then glued the sheet metal over the hole using "Fuzor"

http://www.lord.com/products-and-solutions/adhesives/automotive-repair-adhesives/product.xml/289

Then painted over it with "POR 15"

The result is not pretty! If you want pretty you will have to find a donor car and cut a section out and then cut the exact section out of your truck. Then use a wire feed to weld it in flush. Then grind and paint.

But if you can find a rust free donor bed just use that and replace the whole bed.

 

Thanks for the links! Have any pics of the end result? I started looking for a replacement or doner bed bed have turned up nothing within 1000 miles.