Roof Joint Area at Quarter Panel - Demon w/ Vinyl Top

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Davco

Davco

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I’m concerned with an area on my GL-L-29 and looking for feedback from the group. The area I’m referring to is the roof joint at quarter panel on vinyl roof cars. I’ve attached an image showing deformation of the joint. I’m curious what causes this and what, if anything, I can do to better the situation and avoid making matters worse.

Below are notes from the Dodge Electrical & Body Assembly Manual. Is Plastisol the culprit? The vinyl is in good to great condition for its age and I havnt found any pinholes or areas that would allow moisture inside directly.

Notes:

General Instructions - Sealing
“Apply 2654127 sealer, M.S.CD433 as required, to repair surface defects of the solder replacement sealer, 2654107 M.S.CD430. Application shall be in accordance with P.S.4975.”

Roof and Deck Opng Upr Pnl Area
“Vinyl Roofs:
Std. Comb. Plastisol, M.S.CD430, & solder 2.00 in. on each end.
Opt: 100% Plastisol M.S.CD430 or 100% solder and grind.
Ribbon .25x.75”

I don’t plan on removing the vinyl top to investigate further but would like to know cause of deformation if possible.
The opposite side is not noticeable as much.

IMG_5751.jpeg
 
I don't know the exact cause......we may never know. But the I would say that the terrible prep work the factory did on vinyl top cars was the main culprit. They were simply not finished on top, so rust and corrosion set in quickly on a lot of them. They weren't really interested in those areas, since they were going to be covered up. Over time, the filler and lead shrink as moisture gets between it and the metal. Unless you plan to remove the top, there's nothing you can do. Your car must have been stored indoors a good bit, otherwise it would probably be much worse. Rest assured, "whatever" condition it is in, it's worse than you think.
 
RustyRatRod said:
I don't know the exact cause......we may never know. But the I would say that the terrible prep work the factory did on vinyl top cars was the main culprit. They were simply not finished on top, so rust and corrosion set in quickly on a lot of them. They weren't really interested in those areas, since they were going to be covered up. Over time, the filler and lead shrink as moisture gets between it and the metal. Unless you plan to remove the top, there's nothing you can do. Your car must have been stored indoors a good bit, otherwise it would probably be much worse. Rest assured, "whatever" condition it is in, it's worse than you think.
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I bet you’re correct. I’ve heard it only took three to four shifts to complete a Demon at Hamtramck and ship dates were critical while QC was lackadaisical. Lean manufacturing at its best.

The area really sticks out to me and I hate it’s there but will take it over a matte finish reproduction. I’ll make a point to stay out of the rain and cross my fingers it doesn’t get worse.

I wish all of them received 100% solder and grind though. Would hold up to the elements much better.

*I’ve also heard these LL29 cars had less scheduled hours than LM29 cars.
 
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yep, I agree. These cars were winging down the line and some guy had to finish the joint on the fly. But I wouldn't assume that there is corrosion involved. I would bet that it looked just like that when it rolled off the line. I have a 70 Swinger that has a lump in the part of that seam that rolls over to the back glass. Never changed shape. When I got the car repainted, I asked if they could warm up the original vinyl top, peel it back and fix it. A month later the shop called and guy asks me, "just how original do you want this car to be?"... I asked him what was going on and he says it is a lump of factory filler that was never ground off. I had them just glue the vinyl back down and the lump looks just the same, 25 years later. It goes with the wrinkles in the top above the drip rail on the opposite side C pillar and the seams across the face of the front bench seat halves that miss alignment by an inch (a feature that I have now found on 5 different original 1970 Dart bench seats). I bet that the finisher was just too zealous in grinding the filler flat on yours.
 
str12-340 said:
yep, I agree. These cars were winging down the line and some guy had to finish the joint on the fly. But I wouldn't assume that there is corrosion involved. I would bet that it looked just like that when it rolled off the line. I have a 70 Swinger that has a lump in the part of that seam that rolls over to the back glass. Never changed shape. When I got the car repainted, I asked if they could warm up the original vinyl top, peel it back and fix it. A month later the shop called and guy asks me, "just how original do you want this car to be?"... I asked him what was going on and he says it is a lump of factory filler that was never ground off. I had them just glue the vinyl back down and the lump looks just the same, 25 years later. It goes with the wrinkles in the top above the drip rail on the opposite side C pillar and the seams across the face of the front bench seat halves that miss alignment by an inch (a feature that I have now found on 5 different original 1970 Dart bench seats). I bet that the finisher was just too zealous in grinding the filler flat on yours.
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It’s probably best I quit considering “fixes” for it then and learn to accept it’s part of the car. I’ve never been a big fan of vinyl tops but beggars can’t be choosers and I liked how original this one is. I would like to learn more about “Plastisol” though. Sounds fancy.
 
I don’t know how relevant this is to your situation, but my Duster was only six years old when I purchased it and it already had corrosion forming under the vinyl top. I had no idea that was an issue with these cars and if an army friend hadn't warned me about the potential I likely wouldn't have caught it in time to prevent a serious problem from developing. My car was B5 blue with white vinyl on the forward half of the roof so it looked a bit like a Smurf, which made the decision to remove it an easy one. At the time I didn't know I'd still own the car more than 40 years later so keeping it original didn't seem very important. When the vinyl was removed I found that the joint between the A pillar and cowl panel was left in a really rough state at the factory. I guess they figured it wouldn't matter since the vinyl would cover it. So as others have pointed out that may very well be what's going on with yours since that's exactly where the joint is. But I'd still wonder about the possibility of rust.
 
Tanker said:
I don’t know how relevant this is to your situation, but my Duster was only six years old when I purchased it and it already had corrosion forming under the vinyl top. I had no idea that was an issue with these cars and if an army friend hadn't warned me about the potential I likely wouldn't have caught it in time to prevent a serious problem from developing. My car was B5 blue with white vinyl on the forward half of the roof so it looked a bit like a Smurf, which made the decision to remove it an easy one. At the time I didn't know I'd still own the car more than 40 years later so keeping it original didn't seem very important. When the vinyl was removed I found that the joint between the A pillar and cowl panel was left in a really rough state at the factory. I guess they figured it wouldn't matter since the vinyl would cover it. So as others have pointed out that may very well be what's going on with yours since that's exactly where the joint is. But I'd still wonder about the possibility of rust.
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I’m fortunate the roof joint at front pillar is nice on both sides. No signs of rust or deformation.

IMG_5737.jpeg
 

I think the factory took the cars that had the worst panel alignment and used them for vinyl top cars.

What better way to get rid of the imperfections that would absolutely show on a hardtop.

I think years go by and the padding loses it's puffiness and then the low spots start showing.

This is purely speculation on my part, but it sounds good to me.

Tom
 
PROSTOCKTOM said:
I think the factory took the cars that had the worst panel alignment and used them for vinyl top cars.

What better way to get rid of the imperfections that would absolutely show on a hardtop.

I think years go by and the padding loses it's puffiness and then the low spots start showing.

This is purely speculation on my part, but it sounds good to me.

Tom
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That’s not typical of assembly line production. Sequential process would not allow for it.

What TESLA does now will though. They call it “modular” or “unboxed” and everything is done in separate areas and brought together at “assembly”.
 
xLURKxDOGx said:
Great looking car there! Sitting on 120K or more...........
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Thank you. Insured value is closer to 25-30K (not h-code) but being rust free or near rust free pending what’s under the vinyl is super valuable to me. Paint jail and body work/labor costs is something I want to stay away from if I can help it. I dig aged acrylic enamel anyway.
 
Non Vinyl cars have lead in the seams and perfect quarter to roof transition bodies are used. Vinyl top cars have a water proof plastic in this area. and usually have defective out of alignment bodies in this area.

I have repaired this on many vinyl top car by peeling the original roof back and wire wheeling the plastic out , its soft not like bondo

Replace it with water proof Dura-glass or fiber-strand in the seam to seal it and bondo over top of that for straightening it. Then re-glue the vinyl down with the correct contact cement spray by 3M. If you use care no paint will be needed except for under the vinyl.
 
Pull the interior sail panel and look to see if the pillar is pushed to the inside and see if you can push it out by hand. It looks to me as if someone leaned extremely hard on it and caved it in.
 
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