Rusted out windshield frame repair?

Greetings,

I have a '71 Impala that I'm fixing up, and upon removing the windshield (into which I managed to put lots of cracks) I found that a large area of the frame above the drivers side has rusted away. I had expected some damage, as the entire windsheild area had been sealed inside and out with what appeared to be several tubes of clear silicon, and the interior molding piece had begun to rust through. However, I didn't really expect it to be as bad as it is, and I'm not sure how to go about fixing it. I though I might be able to fill the leaking areas with bondo, but now I see that there isn't much left to which I could stick the epoxy.

The upper part of the frame is mostly gone, Everything except the top 1/8 inch or so below the top corner. The lower piece of metal is still there, but very weak and pitted almost to non-existance, most likely will need to be removed completely. The pitting extends back about 2 inches into the cavity between the upper and lower sheets. The corner where the piller attaches has some damage but appears to be stable.

Here's an image of the damaged area: http://www.genetech.net/~dknaack/rust.jpg

The only thing I can think of is to pull back the headliner and cut off a couple inches of the bottom part and attempt to weld in two heavy gauge straps on the bottom, approximating the original shape, to form the lip that supports the windshield, and then another strap along the top edge, to form the other face of the frame. To this I could apply metal mesh and bondo.

I think that this would allow me to use easily available metal, avoid any complex sheet-metal sculpting (for which I do not have the necessary tools or skills), minimize the welding (which I have never before attempted) and provide a reasonably strong repair.

Is there a better solution that will yeild a normal looking and reasonably durable and waterproof installation?

The only reason I'm doing this is to learn how, so taking it to a professional is not an option.

One thing I'm concerned about is those little pins that the chrome exterior molding clips onto. Several are missing due to the rust (and another broke off while I was removing the molding), so there is no longer anything to attach the molding clips to. Can these be purchased or fabricated (perhaps the head of a suitably sized nail welded on)?

Thanks, DK

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Well the clips are easy enough to screw on or pop rivet but don't get them down too low or the molding won't hook. You can pop rivet sheet metal angles in as needed rather than cut and weld the pinch weld because approximating that shape is more difficult than it appears not to mention tampering with the structural integrity of the vehicle. If it flexes, bing, broken windshield. Pop rivet or weld sheetmetal to the pinch weld then bondo the joints, pop rivets don't distort the metal like welding does and a little bondo and they disappear. Try to keep the bottom surface that the windshield sits on as flat as possible, if not possible you can use a mixture of 3/8 and 1/4 butyl rubber in the low and high spots so the windshield makes contact with the rubber all the way around. The rubber is wound around a piece of cardboard like a snake with a slick strip of paper to keep it from sticking to itself and you roll it on the pinchweld after you apply the primer, keep it to the inside edge, it's better to see some from inside the car than miss the glass completely and be back where you started. You're gonna need a hand setting the windshield in place and the windshields got to be clean on the inside and all the clips have got to be in before you set the glass. Set the bottom on those rubber bumpers, tilt the windshield back some, then put one arm inside the car holding the glass away from the rubber but don't touch the glass where the rubber will, along the top and make your last adjustment side to side so each side has equal coverage then ease it on down making sure you don't hang up on any of the clips. It's best to do it it the warm sun because you have to press, not to hard, the glass into the rubber to ensure a good seal. If it looks like there's a gap anywhere you can fill that with some urethane but never ever use silicone on a vehicle it traps water and you don't want any water laying in there at all.

So have you taken a look at your rear window? I'll bet it looks alot like the front. I've done too many. Wolfman Morehead Ubangi, Ubetcha

How much are we talking about 6 inches 24 inches? And this is the roof right? I was thinking the pinchweld would be left after rust removal maybe just a bridge but at least a base to support from underneath if possible with a strap or to lay an angle on. The easiest way to bridge the rust gap would be the fiberglass cloth with bondo because there's no screws, welding or rivets but whatever you do there's going to be a bump where it laps onto the original, try to keep that to a minimum and the high spot is where you put the small diameter butyl the thicker one goes everywhere else so that rubber touches the glass the whole way around

You can probably push it out once you take the mouldings off. It's difficult to break since it's tempered, cooked in an oven, windshields are laminated, 2 pieces of glass with plastic between. You can make a cut out knife by heating then bending an old steak knife over about an inch then wrap the blade and handle with tape starting an inch up from the bend then you slip the knife blade under the glass and slice the rubber between the glass and body. Then you'll be able to put that experiance from bondoing the front to good use on the back 'cause I guarentee the holes will be twice as big. Good Luck!

Wolfman Morehead Ubangi, Ubetcha

Around 18 inches. I went back and checked it again, and my previous statement about the structural strength is perhaps a bit extreme, I think that if I were to remove all the rust and rivet/weld in a new layer of sheet metal over the pinch weld it would be reasonably strong.

Yup. the pinch weld itself seems to consists of two layers, the upper sheet which forms the exterior portion of the roof, and the lower sheet, which forms the interior ceiling. The portion of the upper sheet that forms the pinch weld and the vertical portion at a right angle to the pinch weld has been completely converted to rust. The lower sheet still has some substance too it, but has some holes.

Last night I picked up some 'Bondo-glass', essentially bondo with glass fibers embedded. I'm planning on removing all the rust that I can and then bending two pieces of iron strap into the right shape and riveting one inside the cavity, just behind the pinch weld, and the other on the vertical area just above the pinch weld. I'll then use the bondo-glass to build out the surfaces for the windshield.

I still have the problem of attaching the molding clips though. I can't really rivet them to fiberglass. Maybe I can drill a hole and screw them back into the iron strap though.

Well, I went ahead and removed the glass. I turned out to be pretty easy because seals had pretty much let loose already, the molding was doing more to hold in the glass than the adhesives.

Turns out that the water was just leaking through the seals, so most of the rust damage is just on the back deck, there are only a couple of small holes around the pinch weld.

However, after I removed all the water damaged material on the back deck, I discovered why the adhesives had let go on that side. The vehicle was apparently involved in a rear-end collision at some point, and the back deck has buckled a bit on one side, and the pinch weld is tilted a bit (the inner edge of the weld is angled up more than it should be).

I'm not sure what do do about this, I'm posting details under another thread, including a couple of pictures.

The back looks pretty good so far

Thanks! DK

Sent via Deja.com

I'd start working on the pinchweld on the back window trying to get it all flat. Occasionally checking with the window should show where the high spots are and how far you need to bring it down. As to the windshield area, I'd get all of the rusty areas out as best possible. That post is very important in keeping the roof up when you have a serious accident that involves the roof and if you just bondo the post together, you will have no real strength and the roof will move very easily.

Sounds good just don't build it out too far or too high. You can lower the bottom supports by redrilling the bracket but there's not much room side to side unless you eliminate a few side clips which isn't a problem if the side mouldings have a screw that holds the bottom on. Remember to use the mouldings as templet guides when you do the bondo because they don't bend they just kink, if worse comes to worse tho you can forget about the clips and the mouldings and use that push in rubber moulding like most new cars use now.

Sure you can you use a washer the diameter of the rivet, a 4-6 which is a long 1/8 diameter rivet and a #6 or 8 sae washer will keep it from pulling thru the bondo. If you can there's plastic clips that will work; they're not as lethal to the glass as the metal ones and they don't rust they're also easier to rivet on.

Looks like you got somewhat lucky. I've seen holes big enough to throw a cat thru. You should be able to tap that down with a body hammer and dolly. Strip all the old adhesive off and get a good coat of paint for a new bed. You can set some pads around the pinch weld to rest the glass on when you check the fit. Make sure they're 1/4 inch or thicker or the bottom sides won't wind up where you thought they were. I love the smell of bondo in the morning . . . . . it smells like victory!!

I finished rebuilding one side and I'm pretty happy with it. I ended up putting a single piece of 18x1x1/8 inch iron strap inside the cavity of the roof, just behind the rusted out pinch weld. I held it in place with a single rivet on the end closest to the rear-view mirror, then squished the Bondo-glass in all around it. After sanding it ended up between about 1/4 and 3/4 inches deep. I wanted to put a few rivets on each end, but there wasn't enough metal left to rivet to by the post (that I could gain access to without some more serious tools), so I'm just depending on the fiberglass to hold everything in position.

I also cut some holes in the inside roof so I could access the back of the iron strap, to apply more fiberglass. The strap is completely encased in fiberglass. I don't think its as strong as the original structure, and would probably come apart if the vehicle rolled or sustained a very hard front or side impact, but I think it'll hold up with no problems under normal use.

After sanding and coating with primer the surface is pretty much exactly like the original metal in appearance, fitting the windshield will be trivial.

Heh, I don't have to throw her, she's made herself perfectly at home in the trunk, accessing it by way of the speaker holes in the rear deck

I've adjusted the pinch weld and I think it will be sufficent. I wasn't able to do much with the slight warpage of the back deck itself. I crawled into the trunk with a light and compaired the two sides, and I can see where there are some slight differences, but the damage appears to be limited to the back deck and small part of the metal to which it is welded. I doubt I'll need to do anything with it.

Anyway, thanks for the suggestions, things are going well so far!