Undercoating. Ugh.

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One thing the internet is good for is being an unending source of conflicting information.

Undercoating. Is it factory, dealer, PO? I'm removing it now it is bare metal underneath in the center of the bed. The rear wheel wells have paint.

Oh, and I thought removing the Line-X from the interior was a pain...

20220511_091411.jpg
 
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One thing the internet is good for is being an unending source of conflicting information.

Undercoating. Is it factory, dealer, PO? I'm removing it now it is bare metal underneath in the center of the bed. The rear wheel wells have paint.

Oh, and I thought removing the Line-X from the interior was a pain...

View attachment 3006032
Apologies for hijacking your thread here, but some kind soul provided my floorboard with a generous coating of bedliner (of unknown origin, but it looks like Line-X, or equivalent). How did you remove yours? To be clear, I'm prepared to sand, prime and paint; I'm looking for the best removal method here.
 
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I believe factory is body color. Any undercoating was dealer added or owner added. Mine is coated pretty well but not completely like it would be if it was done at assembly. Also the bottom of some original sensors and hoses is also coated, so definitely done post assembly.
 
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You might want to investigate Dustless Blasting. Because water is involved there is no risk of warped panels from the heat created with standard blasting. Since you don't know the type of original undercoating the correct chemical stripper would be trial and error.
 
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I do not believe undercoating was ever factory. Dealers were the ones who offered this and usually in wet/salty areas. Had to pay for that "tru coat".
That's what I'm talking about. I don't think it would have left the factory with bare metal underneath. Or maybe it did, but if so, I as a customer would have walked out knowing Toyota short cut their work.

Yes, this was clearly applied after the tub was mounted to the frame. But the bare metal on the bottom of the tub floor has me wondering.
 
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OPMACHINE

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My 1979 has primer on the bottom and what I have assumed was a dealer installed coating.

I watched a guy strip the Line-X out of his truck bed by cutting the tip off his sawzall and using it like a chisel. I would blast it off.
 
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You might want to investigate Dustless Blasting. Because water is involved there is no risk of warped panels from the heat created with standard blasting. Since you don't know the type of original undercoating the correct chemical stripper would be trial and error.
It's basically roofing tar. Pretty sure blasting would do nothing but bounce off. I've already blasted the top side of the tub. It would take a lot of heat to warp the tub, there are stiffener ribs pressed all over this thing and the sides have fender wells spot welded to them.

I am a little amused when I read all the warnings of heat warping from blasting. I am using a torch to soften the undercoating and it scrapes right off with a putty knife.

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Apologies for hijacking your thread here, but some kind soul provided my floorboard with a generous coating of bedliner (of unknown origin, but it looks like Line-X, or equivalent). How did you remove yours? To be clear, I'm prepared to sand, prime and paint; I'm looking for the best removal method here.
Mine was Line-X (receipt from PO) and about 1/8" most places, but 1/4" in some spots. You have to cut it into strips 4 to 6 inches wide with a sharp box cutter. Then get a corner started with a putty knife and pliers and pull. Takes some effort but it comes off.

Bed liner.jpg
 
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Mapp gas, heat it up without catching it on fire, then use your putty knife to scrape it off.

It sucked.
 
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That's what I'm talking about. I don't think it would have left the factory with bare metal underneath. Or maybe it did, but if so, I as a customer would have walked out knowing Toyota short cut their work.

Yes, this was clearly applied after the tub was mounted to the frame. But the bare metal on the bottom of the tub floor has me wondering.

I have more than one FJ40 and one was undercoated and one was not. The one that is not undercoated has the same body paint as the whole FJ40. The undercoated one is probably the same but if you try to remove "just the undercoating", one seems to get to bare metal pretty quick. I know this video is on MUD in a few places, but look again and by the end of assembly the whole body seems painted from factory.

 
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I have more than one FJ40 and one was undercoated and one was not. The one that is not undercoated has the same body paint as the whole FJ40. The undercoated one is probably the same but if you try to remove "just the undercoating", one seems to get to bare metal pretty quick. I know this video is on MUD in a few places, but look again and by the end of assembly the whole body seems painted from factory.


There is no paint under it on mine. The sill, where it wasn't rusted, had no paint on it either. Maybe mine passed by mistake.

The brown is just residue from the undercoating.

20220511_152958.jpg
 
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There is no paint under it on mine. The sill, where it wasn't rusted, had no paint on it either. Maybe mine passed by mistake.

The brown is just residue from the undercoating.

View attachment 3006269

I certainly would expect Toyota to never let an FJ40 leave without a coating, quality control you know. My 1969 was undercoated from the dealer in 1969. I did some work on the rear sill and where there was undercoating, when I got it off bare metal showed. I wrote it off to years of undercoating sprayed on acrylic enamel paint enduring the weather.
 
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I certainly would expect Toyota to never let an FJ40 leave without a coating, quality control you know. My 1969 was undercoated from the dealer in 1969. I did some work on the rear sill and where there was undercoating, when I got it off bare metal showed. I wrote it off to years of undercoating sprayed on acrylic enamel paint enduring the weather.
Possibly an anomaly, but there was zero evidence of any kind of paint. Perhaps they just did a phos treatment and called it good. As I believe I mentioned, there is paint in the wheel wells under the tar.
 

thatcabledude

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Mine was Line-X (receipt from PO) and about 1/8" most places, but 1/4" in some spots. You have to cut it into strips 4 to 6 inches wide with a sharp box cutter. Then get a corner started with a putty knife and pliers and pull. Takes some effort but it comes off.

View attachment 3006146
You were blessed that they did a crap job of prepping.
 
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It is an asphalt product, even smells like roofing tar. If it were super frozen with dry ice, it might work. But at room temperature it will just put a bunch of dimples in it.

Use a plumber's torch, heat small areas about 4x4 inches, keep the torch about 6-8 inches away so it doesn't catch fire and only until soft, about 5 seconds, then scrape with a putty knife. You want it soft like clay and it comes off nice and clean (mostly). If it is too hot it will melt. It will still come off but will be messy. A few seconds to cool and you're back in good shape.

You were blessed that they did a crap job of prepping.
I don't know. Looks like they scuffed it with 80 grit on a DA. A bunch of factory paint came up with the liner. They did do a lot of short cuts, however. Like lining over rust. The bed has dozens of holes from self drilling screws, and they just put masking tape over them and sprayed. Didn't remove any dents on the floor, either.
 
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