Found Rust, Not Certain How to Fix

[lookforjoe]

I don't see needing the torsion box at this point. Yes, there is rust on the inside of the box. I'd cut a little higher up on the inside skin so you can get inside the box & de-scale what you can. If it seems mostly intact, you can treat the exposed metal, then make a repair patch for the floor/inner skin.

 

[CRatcliff]

Ooooh okay! That's excellent news and I'm gonna do that. I think I need a grinder wheel, rather than the flap disc I'm trying to go with - it's slow dang going right now.

 

[lookforjoe]

If that is an angle grinder, get cut-off discs. You can slice a clean cut that way.

 

[lookforjoe]

Afterwards, you can make a cardboard template & cut a piece of sheet to fit nicely in the opening, you want butt-welds for this, no overlap. Similar to what I did with removing the door handles here, just angled in your case to go from the vertical to horizontal plane

 

[CRatcliff]

Awesome yeah I have cutoff discs, was just worried about cutting too far with them. Was thinking grinding out the rust until it stops, then cutting around that

 

[lookforjoe]

Awesome yeah I have cutoff discs, was just worried about cutting too far with them. Was thinking grinding out the rust until it stops, then cutting around that

I'd cut out along these lines, then clean up from there. The bottom edge you are cutting a clean line through the inner skin, not the torsion box/outer skin

 

[CRatcliff]

Okay awesome. On it today

 

[CRatcliff]

Hey all! Sorry for the delay on this. Finally got it cut out today, and the good news is that it looks like the rust is only on the bottom, but the bad news is that it looks like it goes pretty far over. Thoughts on how to proceed?

 

[VolvoGLT]

Doesn't look too bad honestly. I think most of the rust flakes are from the top panel. Vacuum out the cavity, try to remove as much rust as possible with those black/purple abrasive discs, put on some rust converter, then epoxy, paint. Are those rubber plugs sticking up? If yes, I'd remove them after you are finished welding the new panel and spray some liquid wax or similar in there.

 

[lookforjoe]

Yeah, scrape out large flakes, wire brush, apply rust converter & either paint or move on to fitting the repair panel. All interior box sections are going to look like pretty much like that, so it's not worth stressing over too much, as long as the panels are generally sound.

 

[CRatcliff]

Awesome awesome, thank you guys. Honestly agreed it doesn't look too bad - I'm mostly not certain how the heck to reach that tight cavity to the left (you can see it easier in the video). Any advice on a tool / method for that? I'd love to not cut any more out if at all possible.

Thank so much for all of your help with this. This project was so stressful - I hated cutting up my baby, but once it's done, knowing that it's been treated / rust proofed for a while will be so nice.

 

[142 guy]

Ooooh alright. I've got the wire wheel on the grinder and might even hit it with the flap disc for a minute.

Also I'm pretty sure the leaks I found were actually at the tops of the seams of the firewall. Already cleaned and re-sealed them, but I'm realizing I may have wanted to hit it with some rust-converting primer or something first.

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I don't want to be a downer; but, given where that rust is showing I would be inclined to get into the wheel wells and examine the back part of the wheel well that is formed by the extension of the firewall. The best way to do this is by removing the fender. That outside area is typically covered in undercoat and the undercoat peels back and traps moisture leading to rusting along the seam where the inner wheel well is attached to the fire wall. Extending up from that point check the inner fender / wheel well where the hood hinges mount to the inner fender. Scrape away the undercoat and it would be normal to get an equally nasty surprise.

If you don't want to or can't manage a rotisserie restoration (what I did) then you need to do this one small repair at a time. Select an area where the repair can be limited, start and finish it. Only if it butts up against another repair area and the repair technique would dictate expansion of the work should you expand the scope - i.e. you decided that a complete chassis box extrusion needed to be replaced.

If you do go looking for and discover other rust spots, if you plan to carry out a proper repair do not do temporary repairs that involve seam sealers or things like POR 15. Having to clean that stuff off when it does come repair time will just add to the misery. Spray it with something like Rust Check Rust Inhibitor. WD 40 would probably work; but, is really runny by comparison. This is fairly thin bodied and will work its way into crevices to displace moisture and impede further rust development. Its big up side is that it will wash off fairly easily with solvent.

Been there and farmed out the repairs after I stripped the body and discovered all the nasty surprises.

 

[CRatcliff]

I don't want to be a downer; but, given where that rust is showing I would be inclined to get into the wheel wells and examine the back part of the wheel well that is formed by the extension of the firewall. The best way to do this is by removing the fender. That outside area is typically covered in undercoat and the undercoat peels back and traps moisture leading to rusting along the seam where the inner wheel well is attached to the fire wall. Extending up from that point check the inner fender / wheel well where the hood hinges mount to the inner fender. Scrape away the undercoat and it would be normal to get an equally nasty surprise.

If you don't want to or can't manage a rotisserie restoration (what I did) then you need to do this one small repair at a time. Select an area where the repair can be limited, start and finish it. Only if it butts up against another repair area and the repair technique would dictate expansion of the work should you expand the scope - i.e. you decided that a complete chassis box extrusion needed to be replaced.

If you do go looking for and discover other rust spots, if you plan to carry out a proper repair do not do temporary repairs that involve seam sealers or things like POR 15. Having to clean that stuff off when it does come repair time will just add to the misery. Spray it with something like Rust Check Rust Inhibitor. WD 40 would probably work; but, is really runny by comparison. This is fairly thin bodied and will work its way into crevices to displace moisture and impede further rust development. Its big up side is that it will wash off fairly easily with solvent.

Been there and farmed out the repairs after I stripped the body and discovered all the nasty surprises.

Totally get that, and agreed! I abated the rust on the inside, but once the inside project is done the fenders are coming off and we're gonna clean up the other side and treat it and make sure it's not fucked

 

[CRatcliff]

Hey all! Bumping this for advice on how to get into that cavity to clean the rust up!

 

[CRatcliff]

Hey all! Apologies, but bumping one more time. I keep looking at this and trying to figure out how to get in there and would love any advice

 

[CRatcliff]

Rust is cleaned out as well as I could (it's too tight to reach further). Do you think that's a good enough clean out to POR15?

 

[lookforjoe]

Rust is cleaned out as well as I could (it's too tight to reach further). Do you think that's a good enough clean out to POR15?

I'd just use a good rust converter & then paint. POR15 makes a hard shell. Any areas where moisture gets in will just trap moisture.

 

[CRatcliff]

Ooooh ok! Any advice on a good rust converter? All my googling has just resulted in POR15

 

[mitch1971]

POR15 isn‘t a good choice, most likely to disbond. Get some 2k epoxy primer, ideally 2k epoxy mastic primer. A good epoxy is very surface tolerant compared to anything else out there and 2 or 3 coats will last forever and no rust will get through. Go direct to steal, don’t bother with rust converters, use them where you can’t access. A rust remover gel if you want to fully remove the rust, slap it on, cling film over and leave. Ideally give it a scrub with a wire brush every couple of hours until all the rust is removed. In the U.K. I use Deox gel, don’t know what brands you guys have. Epoxy mastic I use Jotun Jotamastic 80 or 87, fantastic stuff. We use it on our offshore oil platforms.

 

[CRatcliff]

@mitch1971 thank you thank you! What would you use for the converter? As you can see in the pictures there's no way I can get in that cavity - I was able to get some of it with a long bit extender on my drill and a wire brush, but there's a 90 degree left bend there etc, so I need something I can just spray around or something.

I was thinking of using some naval jelly on the easy to reach stuff in the cavity, but I wouldn't be confident about neutralizing it.

There's just inevitably going to be some rust that I can't reach, so I really think the solution is a converter spray.

I was thinking Permatex might be the move, but would love your advice! I know the converter spray turns into a primer, so my plan was to spray some 2k paint over that to protect it.