Door Seam Seal Rust fix

Hi all, so the only rust on my 95 4Runner is along the bottom of the doors where the seam seal is. I assume the drains were clogged over the years and caused separation of the seal. Now the issue is, I need to understand if this is something I can easily tackle myself or if I should go to a shop. The issue is I do plan on likely doing a full repaint within the next year possibly, so I dont want to pay for services twice since this would get repaired during my repaint. I guess my first question is, are my doors screwed? Is it even going to be possible to repair this? I was thinking that if I did it myself, I could remove the old rotted seal, sand everything down, use a rust inhibitor, and then lay down some fresh seam seal and then spray with a paint matched rattlecan. It wont be perfect but it can always be repainted when the truck gets done. Attaching some photos to get your thoughts. Note that this is the worst door (drivers), but 2 other doors have a similar issue just not as bad

 

Recently sprayed mine with Blaster shield, but i don't have rust and i would advise against doing it if your going to get it painted as it will cause issues.

Going to someone to repair is probably the best idea since the door trim will all need to be removed and everything inside the door will need to be cleaned up and repainted with something Rust preventative.

 

Thanks for the advice. Honestly I've gone to two shops and both seem hesitant to touch it because it's an old truck and they think I should either do it myself or go to a restoration focused shop. I think they're concerned about the seals and clips breaking and then having to source and replace them on an old truck.

They basically told me that they mainly deal with collision and stuff for newer cars so I'll either have to find a smaller body shop or attempted myself.

Ive been thinking about trying one door myself. Sand, clean up, then something like POR15 and then paint matched spray.

Honestly I think my first step is at least taking a look to see how far it spread

 

Take the inside door trim off and see how bad it is inside, that's going to be key to know how bad the rust really is. Then you can sand and paint.

For the door trim weather stripping you can get these very thin foam (like pool noodles) to push through the weather stripping to give them life again.



Worse case you can repaint the outside so it looks good and use blaster shield on the inside to stop the rust form getting worse.

 

It is not possible* to permanently fix something like that, but you can postpone the rust. I recommend against sanding and painting, it will come back very quickly and you will be back to square one.

First, clear out as much of this rust as you can, taking care to also clear out door drains. Remove part of the door seal and wash out all grime, use power washer if you have it but make sure to not use it on rubber seal. Then use a brush on the affected area. Some suggest metal brush, but I'd use plastic to remove existing rust while minimizing impact to surrounding areas. with this, you are not going for perfect shiny metal, you are looking to remove large paint and rust flakes that can trap moisture. Let all of this dry, ideally leave it in the sun with doors open for a day (mind your battery).

Second, apply rust converter to the affected areas. I use Rust-Oleum, but there are other alternatives that would do as well. Let it dry for a day.

Third, and most important, apply oil-based rustproofing. Fluid Film or Krown. If you want to be really through, remove door panel and clean and spray inside the door too.

Last but not least, have you checked your frame for rust? If they salt roads where you live you need to use oil based rustproofing or risk losing your truck to frame rust.

* Permanent fix is to take doors off, strip to a shell, sand blast, dip and repaint. This is very costly.

 

This it's really helpful and I appreciate the advice. Can you elaborate a bit on why you think it's not possible to permanently fix it without stripping everything down? If I were to try my best to clean the drains and then remove all the rust and repaint, as long as the drains are clean wouldn't it in theory be permanently fixed? I guess your thoughts are that inside the door there are likely damaged sections of the paint that will hold on to moisture and just cause the rust to spread that are pretty much impossible to get to without fully stripping everything down?

 

I had a car, not a 4Runner, that had bottoms of front doors rust out. It started pretty much like what I see in your pictures and got worse over time. The issue is that T joint with factory sealant is hard to clean and seal from both sides. That is, there is always some rust behind something. The only fix that finally worked for me was cutting entire bottom out, welding new part in and priming and painting it from both sides (and also painting the door outside). In a hindsight, I should have just gotten new door shells as it would have been just as much work.

Now, what I did not know back then is how effective is a combination of rust converter and fluid film. I probably could have saved it if I got on top of that as soon as I noticed bubbling.

In my experience, if you keep using it, in 2 years it will start bubbling up again and in 5 years you will be back where you stared. YMMV.

 

The rust you are seeing is between the inner door frame and outer door skin
This is where the stamped inner door and stamped outer door meet.
This area is supposed to drain, it has a few slots in it across the bottom of that inner door frame/skin.
What happens is the rubber trim along the bottom of the window dry rots and cracks and allows dirt and leaves to get in the bottom of the door which then turns to wet organic matter that eats the painted coating off the inner door frame, and eventually leads to rust. This rust slowly creeps down the door skin and door frame until you see it eating under the paint.

To fix this and fix it professionally you are going to have to do some cleaning inside the door, sand blasting inside and outside the door, preventative sealing and coating of these sand blasted areas, and most likely then a light thin film of filler putty to smooth out the rusty surface on that lower skin if you dont just paint over the rough area. But after all this you will then prime and paint body color if you want a professional repair. The only hiccup would be during and after the sand blasting, what happens if you have major rust and the sand blasting blows holes in the door frame and you then need to patch the lower half of the door or find a new door.

Maximum amount of work would be replacing the whole outer door skin and repairing the inner door frame. Its gotta have enough meat to weld a new outer skin to though.

 

As a preliminary attempt, if I remove the inside door panel, electronics, etc (essentially get access to the window motor and door internals) is that going to give me the visibility inside the door that I need to assess this?

 

Yes you can see the bottom of the door when you gut everything out.
You will need to take a long thin flat head screw driver or pick tool and scrape all the gunk out of the bottom of the door, vacuum it all out, scrape it all good. Then sand blast it to get the rust out from between the two halves of the inner door frame and outer door skin where they meet. You wont be able to get a wire brush down in there to get rid of the rust, you will need to blast it out. Then you will need to clean clean clean. Then you need to seal it with an epoxy sealant or rust preventative primer and then paint it.

Once you understand how the inner door frame and outer door skin meet, you will understand there is a tiny V down at the bottom of the door where the outer door skin wraps around the inner door frame. The rust is down in the bottom of that V and you gotta get it all out otherwise its going to just come right back.

 

Thanks, this is what I figured. Ill have to take a look and just assess how bad it is. Im hoping taking inside panel, vinyl, etc doesnt cause any issue when I try to put it back together. I imagine it has never been off in 30 years.

Anyway this is how I am picturing the bottom of the door based on your description:

 

it’s like this for the most part

 

Got it. Makes sense. I can see why there really is no way to do this properly without getting deep into that groove and making sure its 100% clean and protected. I was originally thinking I could clean it off from the outside and repaint but the real issue is on the inside.

Thanks again.

 

Yes the problem is down in the bottom of that V
There is organic matter, pine needles, leaves, dirt, and it’s all holding water and rusting the inside of the outer door skin and bottom lip of the inner door frame.
basically those two pieces of sheet metal meet and are rusting between them in a tiny crevice so small you can’t get a screw driver in. It’s a tough fix to fix it right.
Clean the crap out of it
Suck it all out
Spray it down with Krown or fluid film or cosmolene and let it seep thru. It will eventually start making it way out the seam where the two pieces of sheet metal meet. Spray a little on the door lip behind the rubber trim let it soak thru under the paint. Wait about two weeks and clean it all up and polish the paint and let it ride. This will at least minimize or stop the spread

 

Ok and just to be clear, are you saying I dont necessarily need to get the rust gone to bare metal in there? I dont really have access to sandblast, so what if I clean the best I can with tools, compressed air, etc.. then fill the bottom of the door with one of the products you mentioned? I assume that even if there is some rust/corrosion in there, as long as it all gets saturated with the fluid film, and I prevent future grime from getting in there it should be ok.

I really doubt my ability to get the inside 100% clean and down to metal using my available tools.

In addition, Im guessing I need to inspect/replace my weatherstripping to prevent this from happening again and clogging the drains

 

Since it would be pretty much impossible to get all the rust out of that seam, the first product I would put in there would be a good rust converter (the thinner the product is the better it will seep into the seam) which should neutralize any remaining rust and THEN add whatever protective coating over that!!

 

The bottom of the door gets full of "stuff" that collects and turns into mush/mud and holds moisture and the organic matter is what eats the primer off the metal and starts rusting everything away. You will want to get everything out of the bottom of the door you can, its tough but get it all out. If you look in my previous replies i said
"to fix it right"
To fix it right would require sand blasting, coating, priming, painting, and some luck.
The more cost effective way is to just try to prevent it from getting worse. Getting all the gunk out of the bottom of the door will allow water to run out the square drains in the inner door frame as designed. Then when everything is clean and dry, you can spray it with Krown, Fluid Film, WoolWax, Surface Shield ect. This will at mimimum encapsulate the rust and stop water from getting to it in the future and stop it from getting worse. If you put a good coating inside the door, its going to oooze its way to the outside of the door. Wait a few weeks then wipe it all down, clean it, maybe acetone on the lower door where the paint is bubbling up, maybe even sand that bubbling paint and prime it and respray it with something to seal it up. This is the cheapest "easiest" fix that will at least hopefully stop it from getting worse.

If you have ever used FluidFilm and WoolWax, you'd know those things crawl up stuff. Sure they run outward and downward like crazy but if you spray them inside something, it will come out and get everywhere and it will somehow slowly climb up frame rails. Its some tricky stuff, but it works well.

 

Yes but Fluidfilm nor WoolWax converts rust and will just encapsulate any rust left which will continue to spread, which is why a rust converter should be used first and then use one of those.

 

Do any of you have tips or things to watch up for as I remove the interior door panel and electronics? Any tools I should grab to decrease the likelihood of cracking plastics and clips?

 

Definitely get a trim tool kit, they have them at harbor freight. I use them all the time for various things. But the door trim should be pretty easy ether way, lots of videos online if needed.

 

Repairing rust with a long lasting solution is possible. I learned about OSPHO chemical rust converter when maintaining iron and steel engine parts on boats continually in the ocean. Salt spray would go everywhere there was air.

Basically scrap loose scale with hand metal tools that fit the space. Suction out with shop vacuum using hose tips that fit the space. Continue cleaning with wire brushes and suction dust.
Then liberally brush on the OSPHO. A couple heavy coats allowed to react overnight will change brown rust to a grey inert stable compound. I usually rinsed with clean water/nylon brush then fully dried the metal.
Paint with a quality oil rust prevent coating like rustolium. Then topcoat with paint color that blends.
I would get very few areas of breakthru rust over years of use. I would retreat any breakthrus as needed.

 

This is exactly what my plan is. I am just waiting for some new seam seal to arrive so that I can replace what I wind up cutting off/removing from the rust

 

Figured I would use this thread since its the same topic. I pulled the rubber seal from the left side doorframes because I saw caked on dirt. I washed and lubed the seal but now I of course have some rust to deal with.

What should I do here? Im thinking light sanding, clean, touchup paint and call it a day? Would something like lithium grease spray instead of repainting be a better protection to sit under the rubber? Or maybe just rust converter and nothing else?

I'm obviously looking for protection here and not beauty since its hidden under the seal

 

Hey so I bought Eastwood Rust Converter and Encapsulator products. The convertor came in a bottle with a spray pump. Is this the sort of thing I need to be careful to keep off the painted part of the door, or does it only react with rust specifically? I know the Encapsulator is like a primer so for that I will be specific, but I am not sure if the converter can ruin my paint if I am not careful. Any idea?

 

I haven't used that particular product, I would suggest test it on a small area that isn't that visible. you should be able to once it's dry paint it with your touchup paint, it converts the rust to an stable iron oxide and seals like a primer, once dry it will turn black.

The following is off their website..there's more info on their website but I saw nothing as to what it might do to existing paint.

https://www.eastwood.com/eastwood-r...gV8RV3VyMalPrhHoXtJFoDsg2ZWlwZnUaAle0EALw_wcB

"Eastwood Rust Converter. This acidic paint is formulated for panels and parts that have heavier rust but still are structurally intact. By spraying or brushing Rust Converter on the surface, you trigger a chemical reaction that turn residual rust into more stable iron oxide. It also forms a paintable black protective coating that is compatible with most topcoats. Last but not least, Rust Converter seals the metal to help prevent future corrosion.

• Rust Converter stops residual rust, and turns it into a black, protective, ready-to-paint coating, without sanding. Just apply to transform the rust
• Penetrates faster than other brands
• No sanding needed - just apply to transform rust"

 

Get a small sisal brush
I normally pour a bit of the rust converter in a cap and use a small brush to brush it on. You can even use small kids paint brushes. I get a pack from dollar store and use them. They are one-time use, the rust converter gunks them up so just get a cheap brush and brush it on and throw it away when you are done. A cap full is enough to brush on that two or three coats. The yellow one in this pack is perfect for small stuff like that.

 

Thanks so much both of you. For example in my post here: https://www.4runners.com/threads/door-seam-seal-rust-fix.46977/#post-778272 would you advise me to knock that down with sandpaper first? I was planning to sand so its as flat as possible before adding the converter. Obviously on the inside of my door panels I am not going to be able to do this, so I was just going to clean as much as possible and then use the converter. On other spots though like in the post I linked, I was thinking I should sand as much as I can.

 

I would first use a small wire brush to get all the loose rust and paint off, you can then sand it lightly if you want.

 

Thanks. I appreciate it. this is new territory for me so I dont want to destroy anything. I just want to keep this thing from progressing until I decide to either paint the whole truck or something else.

 

Hi all so as I wait for the rest of my parts to come to fix my coolant system I figured I'd give a shot at this rusty door today. I got everything off I'm actually really surprised at how little dirt was in the door skin and in fact the drains were completely clear. It seems to me that this is actually an issue with the factory seam seal slowly separating because of drying and cracking and allowing moisture to sit in it. I really cannot find any evidence of rot inside of the door. I didn't want to rip all of the moisture barrier off but I did pull it back a bit and get my phone in there to take a peek and I don't see anything concerning. Would you still rip off all the moisture barrier and get some rust converter in there? I put rust converter on all of the visible rust spots as well as the exit of the drains so now I'm just going to wait for it to cure before I do some encapsulator and paint with some fresh seam seal. I also cut away the section of separated seam seal but I didn't want to be too aggressive and rip away the parts that are still mostly connected so I just got as much converter in the gap as I could and I plan to paint all of this after putting some fresh seal.

I imagine that if the door was actually rotting from the inside that I would see much more obvious damage? I blew some compressed air in there as well and not a single thing came out...

I do wonder if I should be a bit more aggressive in ripping the old seal off though I just don't want to make this job way worse and start peeling away good parts of the door. I figure if it's still mostly attached as long as I put the converter and encapsulator in there and paint over everything it should stay healthy. The last two photos show the part of the seal that I decided to leave because it's still fully attached especially on the bottom edge and unless I pry it off with a screwdriver it's definitely not going to crack off. For comparison the rest of it just came right off with my hand