Hi, as the title reads a Toyota tech spotted two suspicious areas on the frame rails near where the underbody tie bar, or x-brace (whatever it’s called). The area looked like a heavily corroded spot on the passenger side. When he tapped it with a hammer it crumpled and you could then see a clear hole through the frame. There was one more spot on the same exact area but mirrored on the drivers side. When he tapped it the hole was mush more circular but again, seem to crumple clear through. See the two pics I took. Sorry this is all I have for now.

Two questions:

1) how bad is this and what should I do to fix it? I took it to a frame/custom shop this afternoon and the frame guy was a little perplexed about this next question…
2) do the frames of our 4th gens have two walls as the rails transition from the straight side of the car up along where they curve toward the front? When I stuck my finger in the newly made holes, you could feel two distinct walls. One was the hole and then it seemed like an entirely different frame underneath the frame. The frame guy wasn’t sure if it was built that way or if a previous owner tried to weld in a frame kit to hide the deteriorating frame.

Has anyone heard or know of what I’m talking about with the two distinct walls? Sorry that’s the only way I know how to explain it. Maybe I can get better pictures. Any opinions or insights are welcomed. He thought the car was safe to drive for now but recommend welding and entire rust remediation with new coating on the entire frame. He quoted $3-4k.
Thanks

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Typical 4th gen frame (and all gens) problem for those of us who live in areas where salt used on roads in winter. Your AC drain line will aggravate it on pass side, reroute it from engine compartment dripping on top of pass side frame rail away from frame.
I spent $1000 for two patches welded on to my frame and a frame clean out. You need to power wash your frame whenever possible in winter and inspect and treat with some type of rust inhibitor during summer. Lots of discussion on this subject on this site.

@rdruss

This is really good info. Thanks. So I think the tech said this is a common spot because the AC drainage so it sounds consistent. So do you think these size holes should be repaired right away? $1000 is what I was quoted for just the repair job but they said they couldn’t get to it till February.

Should I go somewhere else and get done right away?

Thanks

No, I wouldn't rush to have it done, that's a really minor hole in the Toyota scheme of things. I had many more and much larger holes in my '83s frame before I started patching them. I eventually had to replace the frame, you can only do so much patching

And be on the lookout for more rust, cause as the saying goes, "rust never sleeps".

Many of these rust holes happen from the inside out. Dirt gets in the frame and sits with the salt and moisture which makes the corrosion. That top one will be sizable once cut back to good metal, you can tell by the metal color. I've been repairing 1 or 2 every year when I look before winter. You can see some pics if you search my name. It's probably pretty bad behind the rear bumper too.

As for layers, there may be where the sections are welded together. Otherwise I don't recall any layers on where I've welded patches but these things rust in layers like a saltine cracker.

I wouldn't panic, it been going on for awhile, it's just that now you've noticed it. I had an 8" x 2" hole in the bottom of my frame from the AC drain for a year before I had it patched. Start wire brushing and sanding rust spots and applying some rust inhibitor, if you off road your frame is probably half full of dirt/sand so when it gets wet it stays wet in there for awhile and aggravates the problem. there are drain holes in the bottom of the frame so putting a hose in one on the side up toward the front and letting it run for awhile will probably help get some of the debris out. There's a long thread on here about this subject, look it up and see what others are doing.

This, is why I use Fluid Film on my frame every fall. I also use a "wand" to get inside of the frame. Works great.

I saw a post on one of the 4th Gen 4Runner Facebook groups this morning where a guy had pictures trying to look into some of the holes in the frame that are supposed to be there. You could see a "double wall" where it almost looked like two layers of steel. Someone in the comments said this is normal and it's not actually two layers, he called it bare steel scaling. Take that with a grain of salt because I don't know how true it is.

So what you're describing might be the same thing. I would think if someone had patched your frame previously that it would be very noticeable. Every frame repair I've seen on this forum is very obvious even if it's done well.

To everyone:

Any suggestions on a quality frame/weld shop in Northern, VA that would do this job RIGHT. Hopefully at a reasonable price. I want her to last for a long time. Greatly appreciate everyones support. I love 4th gen owners. We're all in this together!!


@fourwd1

I appreciate the insights. I want to have this fixed right. The guy I took it to showed me some examples in his shop of their work. It looked really good. He said they charge $3-4k, however thats because they take off a ton of stuff to do it right. The new coating looked like a thin Rhino Liner over the whole frame.

I guess my issue is a) I would like these two holes fixed before the winter so they don't get worse (and peace of mind), and b) the cost to do the whole coating is pretty expensive and not sure I can afford that yet.

@MikeinNH67

I like the tips on cleaning it out. Do you think I should start my own coating campaign? It might not be as good as a pro but I guess a wire brush can go a long way with a rust spray. The key is I need to get all that crap inside the frame, out. Any good tips on the best way to do this? There was a lot of crap in there.

@rdruss

I appreciate the help. I'm kind of worry-wart when it comes to this stuff. I just don't want her being eaten away! Is there anything I can put on top of it as a temporary fix to protect it and stop the damage?

@04rnr

Do you have a link to these items? Thanks

@djpope09

Interesting. I wonder if this is what I felt. Could find. I was confused because I felt like what was behind the hole felt like a very rough, material. Not smooth like frame material.

I thought I had a good way to get it out but this years hole proved that I didn't. I have used air and a vacuum but it didn't touch the deep sludge I had where my last hole formed. Only way I knew it was there was after I cut back the metal to weld in the patch. Had a small bucket of junk I scraped out once I had a big enough hole cut out to see in there. This spot was right at the bottom where the frame ramps up to go over the rear wheel. Really should be a drainage hole there.

I think I used a water hose too at some point.

@MikeinNH67

Appreciate the insight. I don’t have a solution either. I guess the only thing I can think of is run some time of solvent through the frame first, then hose to break it up?

Also, any takers on who does this kind of repair job in Northern, Va??

Thanks again

Not many repair shops seem to want to delve into this. The one I found had a Tundra which had the frame replaced by Toyota, so he was sympathetic to my plight and gave me a quote, which I thought was high, but at least he would do it!

When I bought this truck, if I knew then what I know now about these I think I would have bored a 3/4" hole into the bottom of the frame at the lowest arch points as clean outs. It's like trying to remove packed in silt.

Post #136 shows some pics of my last rust repair.
4th gen frame rust

@MikeinNH67

Just checked your post out. Yea, a bummer. Only good part is that hole seemed small. The really agitating part is these holes are mostly coming from inside out. I can scrape and spray all I want but it doesn’t address the primary cause.

The frame guy that quoted me $1000 for the two holes said he’d blow it out. Not sure how extensive he’ll go. I also need to get back under her and start tapping around. But I’m afraid what I might find out with a light hammer.

Also, if you take a second look at the more jagged hole I have in the pic, I’m pretty sure that was filled with some type of filler and painted over, I say that because around the hole seems like paint is still intact and that spot looked liked bubbly before I tapped with a hammer. Like someone painted over something.

You think my compressed air will help clear out the frame at all?

Well, maybe 2x4 on the bottom frame one and 4x8 on the side by the rear wheel. You can kind of tell where the metal is punky by the color. May as well dig around with a pointy hammer or screwdriver, it is what it is.

Sucks when people cover up issues. Compressed air would help but doubtfull you'll get the sludge at the frame arch corners. I have a nozzle with a 12" extended and bent pipe on it that only did so much. Maybe if you blow air in there while digging with a metal coat hanger. Keep us posted.