Roof cracks

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photorep

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I am preparing my'74 Scamp for paint. On both the drivers and passenger side there are cracks behind the rear quarter windows. I picked out some of the filler that was in one of the cracks and put some primer in it. the other side is untouched. Is there a proper way to repair this so that it doesn't crack after my paint job??
 

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i thought they might be the original seams and after 40 years they only cracked a bit, then that's not too bad
 
If it's cracked, you need to dig it all out. A good thing to do anyway because that's a common rust area.

After you do that, post more pics so we can see what you are dealing with and recommend the best direction to go.

Cracked body filler lets water pool behind it promoting rust so don't be shocked if you find some.

You prevent this with sub-frame connectors.
 
I agree dig it out and start over.If the factory lead is bubbled heat it up get rid of it and start over.
 
If it is lead in the crack, how do I heat it to remove...and what do I replace it with..
 
I cannot answer the lead part, but I think it would just be all flaked out rust so you would just have to remove that. (not 100% on that)
I have heard of guys welding in some square pipe and filler metal to reinforce the roof at local body shops, think of it as in you roll your car and have no support, the roof caves in if you don't do this.
 
Lead can be removed with a propane torch, it melts at 621*F so that's not a big deal.

As far as repairing it, body filler won't cut it. Bondo will absorb water (its a seam after all), and it'll end up cracking in short order. Your best bet is to use lead again- after all, it lasted 40 years the first time.

The problem with that is there are fewer and fewer folks out there that are skilled in using lead to do bodywork. And of course, if its done wrong it will crack again. The body seam will have to be thoroughly cleaned, everything will have to be bare metal. That can be a problem because of the seam, I'd use a metal etch from a paint shop after everything was cleaned to get into the seam. Then it would need to be tinned, then leaded, then shaped with body file. Done right it should last another 40 years. Longer, if you do some chassis stiffening to reduce body flex at the seams.
 
If it's lead and the body seam is in good condition, you can leave the lead in there.

If you have corrosion in the seam and need to remove the lead you have several options but none of them are really good for you and you will want a respirator, not just a dust mask.

You can wire wheel, sand or grind it out. If you use heat like a small torch to flow and scrape it out you will need to remove that part of your headliner and interior or you will catch the car on fire.

In an area like that I would probably use something like this.
(But like I said. I would really need to see what you find once you get it cleaned up.)

http://www.autobodytoolmart.com/usc-all-metal-premium-aluminum-filled-auto-body-filler-p-14787.aspx
[ame]http://uschem.com/products/docs/TDS_ALL-METAL.pdf[/ame]
 
first off its not lead... for whatever reason the mid 70's cars seem to have went to filler vs lead, my 73 swinger is the same way...

best repair is to grind it all out, clean the metal (BUT DONT SAND BLAST), weld it up a bit and then lead it. the tinning process does not work over blasting surface for what ever reason.

also the subframe connectors will help as stated.
 
1968FormulaS340 said:
If it's lead and the body seam is in good condition, you can leave the lead in there.

If you have corrosion in the seam and need to remove the lead you have several options but none of them are really good for you and you will want a respirator, not just a dust mask.

You can wire wheel, sand or grind it out. If you use heat like a small torch to flow and scrape it out you will need to remove that part of your headliner and interior or you will catch the car on fire.

In an area like that I would probably use something like this.
(But like I said. I would really need to see what you find once you get it cleaned up.)

http://www.autobodytoolmart.com/usc-all-metal-premium-aluminum-filled-auto-body-filler-p-14787.aspx
http://uschem.com/products/docs/TDS_ALL-METAL.pdf
Click to expand...

I wouldn't wire wheel, sand, or grind ANY of that lead out. The last thing you need is millions of tiny lead particles to breathe. Strip the interior and use a torch. That's how it got in there to begin with, and its by far the easiest way to remove it. And if its not lead, a torch works spectacular to remove bondo as well. Falls right off after its heated. Just don't breathe those fumes either.

If it weren't cracked, I wouldn't mess with it. But if it is cracked (and it appears to be), then it needs to be removed or any bodywork over the top of it will be subject to cracking as well.

As far as the All-Metal goes, it would hold up a lot better than bondo. That's all I ever do body work with. Harder to sand, but it won't absorb moisture like bondo will. But I still wouldn't use it by itself for the roof seam. The All-Metal is a lot harder than lead, so, more likely to crack than lead would be.
 
I think that's why I said it not very good for you and he would need a respirator.

And yes, the lead can only stay if it's stable, uncracked and without any signs of corrosion in the seam.
 
1968FormulaS340 said:
I think that's why I said it not very good for you and he would need a respirator.
Click to expand...

And you'll still get covered head-to-toe in lead dust. Not to mention covering your entire workspace in the stuff, which will then need a thorough decontamination. If that's how you like do it, by all means, be my guest.

I'm personally opposed to getting covered in lead dust, and I really don't enjoy cleaning all that much either, so I'll continue to suggest that it be done the proper way with a torch. Which also happens to be the safer and easier way. Not only will it get rid of ALL the old lead, that lead will be in a little puddle on the ground. Once it's done cooling you can just pick it up, no need for vacuums and brooms. Heck if you're really tricky, you can put a metal container on the floor to catch the old lead as it melts off the car.

That's also the reason I suggest using a body file and not sandpaper to shape the lead. The body file produces large filings, ie, they don't get aerosolized, and they can easily be swept up. Or caught on a drop cloth. You can then apply a thin skim coat of filler over the lead if any sanding is needed to prevent the lead from producing any significant amount dust in the later stages of bodywork.

If it sounds like I've done this before...

Cheers! :wave:
 
My research leads me to believe that cars with vinyl tops got plastic filler, and cars without them got lead.

There are up to five layers of laminated sheet metal in the C pillar area, forming several different shapes, including "hat", C and box.
 
The use of lead in those seams ended around 1970. Too many on the job injuries related to hot lead. Finishing body filler takes a lot more labor/time than the lead did so all the mfgrs' started pushing vinyl tops to lessen the labor/time required. The vinyl hides imperfections that paint would show.
Todays body filler is much better than what was available back then. If its properly applied it should last a lifetime.
 
My 73 Satellite (no vinyl) and my 74 Charger SE (partial vinyl) both have leaded seams.

My 72 Charger SE (full vinyl) has plastic filler.
 
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