Best seal for Front Windshield ?

[nightman61]

I posted a while back, but received no replies. I located a windshield, I needed for my 73 Newport 2dr HT. It arrived today. After 7 months, but its new. Now, when I got the car, the front leaked bad. The car had not trim around the glass, and the seal that was on it was hanging out. Research indicates no rubber seal around it, like my 67 Newport, and no indication of one I can find. I have tried to research more on what to use to seal the glass. I know modern cars are using a urethane based sealant. I have watched a few videos on you tube, but they don't look like the GM way will work, and I can't locate one that looks like it will work. Any suggestions? Thinking just use butyl tape along top and sides and maybe double row, or triple row a long base. The old seal used on it was more like silicone, and the windshield would not release from it easily, hence the broken windshield trying to remove to reseal. Has anyone ever replaced theirs?

 

[Big_John]

Butyl tape is pretty easy. Cut the old, remove the windshield, scrape out the old butyl and apply new tape. Put the windshield back in.

You are overthinking this way too much. If everything is done correctly, the new butyl won't leak and I think that what you are planning with double and triple rows is a recipe for leaks...

The old seal used on it was more like silicone, and the windshield would not release from it easily, hence the broken

How did you cut the old seal? Sounds like someone installed the windshield with something else besides a butyl tape.

I have always used piano wire to cut it out... The tools with a blade might work for some, but I think it's too easy to screw up and break the glass.

 

[nightman61]

Hey John, I am going to use butyl tape on the install. I used that while resealing the rear glass. When I was removing the front windshield from the car, There was silicone around the top and sides, a long with a rubber seal that was pushed on the glass. The seal slipped onto the glass with a u-shape and had a another piece attached to cover where the actual chrome trim would be. It was coming off, no doubt was not the proper seal. The silicone on the sides and top came out easily. When it came to the bottom, I tried using a blade to cut through the silicone that was used to hold the base, and while it started ok, about 6 inches into it, the glass cracked. From what I can tell, the person that had resealed the window had used a very wide application of silicone, looks to be 1.5 inch wide bead, or more, then pressed the glass onto it, causing a little wider spread. I am wondering about spacers I need to keep the glass out far enough so when chrome trim is reinstalled the glass is where it needs to be.

 

[CBODY67]

Before the current windshield sealing "silicone" evolved to its current level, butyl tape might have been a desired alternative. Even back then, 3M sold dedicated windshield adhesive for such, but over time, they could lose their grip on the glass and seeps started. Which might explain the silicone you found, which could have been an effort to stop any leaks, back then.

To me, for the butyl tape to work as desired, the body would need to be "perfect" and the glass contours would need to be similarly "perfect". No high spots or shallow spots, as those areas could compromise the seal. If not initially, over time.

By contrast, the 3M windshield sealer is much more forgiving as it comes out in a bead. Which might be what you are terming "the GM way". In reality, any "glue-in" glass does not know any car brand use, just "glue-in" compared to "gasketed".

In many cases, rubber spacers (i.e., travel limiters) are placed at the bottom of the glass area, prior to sealer and glass installation, to ensure the glass stays where it needs to and does not slide down as the sealer cures. Usually about 1/4" square and about 1" long?

Rather than using the 3M Windshield Sealer from a caulking gun, it was possible to purchase something like that in a roll of round sealer. It was thick enough to compress between the glass and have a good seal, much better than flat "tape". Unlike the caulking gun sealer, I suspect it would be more sensitive to shelf life prior to installation, even if stored in a controlled environment. Not unlike how the old "strip caulk" would get stiff with age, although stored in its original box. FWIW

I know this might sound unpopular, BUT I would get a local auto glass company to install the windshield with their materials. You do the clean-out and prep so that all they have to do is wipe down the area and commence with the installation. Most have mobile services (to do onsite work at new car dealerships or "as seen on TV" installations). Two reasons, if they mis-handle the glass and it cracks, it's on them. All of the windshield sealer they use has a lifetime warranty, so if it leaks in the future, it's on them AND they can reseal it for no cost (or at least that's been my experiences). This way, too, they know how much of a bead of sealer to use for best results. To me, these things are worth paying somebody else to do. Your judgment call.

Where did you source the windshield from? Just curious.

Please keep us posted on how things progress, whichever way you decide to go,
CBODY67

 

[3C's & a D?]

New reproduction windshields don't have the exact curvature that the originals had. Urethane is the best way to go. You can easily find used windshield stainless trim, and new clips. How's the bottom channel? There's usually a hole or two down there.

 

[nightman61]

Before the current windshield sealing "silicone" evolved to its current level, butyl tape might have been a desired alternative. Even back then, 3M sold dedicated windshield adhesive for such, but over time, they could lose their grip on the glass and seeps started. Which might explain the silicone you found, which could have been an effort to stop any leaks, back then.

To me, for the butyl tape to work as desired, the body would need to be "perfect" and the glass contours would need to be similarly "perfect". No high spots or shallow spots, as those areas could compromise the seal. If not initially, over time.

By contrast, the 3M windshield sealer is much more forgiving as it comes out in a bead. Which might be what you are terming "the GM way". In reality, any "glue-in" glass does not know any car brand use, just "glue-in" compared to "gasketed".

In many cases, rubber spacers (i.e., travel limiters) are placed at the bottom of the glass area, prior to sealer and glass installation, to ensure the glass stays where it needs to and does not slide down as the sealer cures. Usually about 1/4" square and about 1" long?

Rather than using the 3M Windshield Sealer from a caulking gun, it was possible to purchase something like that in a roll of round sealer. It was thick enough to compress between the glass and have a good seal, much better than flat "tape". Unlike the caulking gun sealer, I suspect it would be more sensitive to shelf life prior to installation, even if stored in a controlled environment. Not unlike how the old "strip caulk" would get stiff with age, although stored in its original box. FWIW

I know this might sound unpopular, BUT I would get a local auto glass company to install the windshield with their materials. You do the clean-out and prep so that all they have to do is wipe down the area and commence with the installation. Most have mobile services (to do onsite work at new car dealerships or "as seen on TV" installations). Two reasons, if they mis-handle the glass and it cracks, it's on them. All of the windshield sealer they use has a lifetime warranty, so if it leaks in the future, it's on them AND they can reseal it for no cost (or at least that's been my experiences). This way, too, they know how much of a bead of sealer to use for best results. To me, these things are worth paying somebody else to do. Your judgment call.

Where did you source the windshield from? Just curious.

Please keep us posted on how things progress, whichever way you decide to go,
CBODY67

I purchased from Auto City, off eBay. found out afterwards, while they listed last one in stock, it actually wasn't in stock took 7 months and had to be manufactured from someone else. I did find the manufacture after 3 months of waiting, they sent me a email saying, Oh we have one in stock we can sell you for 2k, or you can wait until December or January and will sell for 600.. that didn't include the shipping cost. Outrageous on what manufactures are doing.. it's a wonder the antique cars are getting scrapped. I have reached out to a couple of companies before, but what they want to install is as much as I paid for the glass itself. I will let you know how it goes..