1960 Windshield frame installation

[Thomas C.]

I just received my completed windshield frame with new glass back from Glassworks, after having tried to assemble the frame and install it a couple of times and ending up with new cracked glass, and am ready to install it on the car.

I have searched and read all the forums both here and on the internet and there seems to be some difference of opinion on the best method of installing this frame. Specifically regarding how to seal the frame to the body. I have the new frame to body weatherstrip available from the repro vendors but Glassworks told me not to use it, that it causes more problems than it is worth. Their recommendation is to use an original if available, or to make my own or use strip caulk.

I know it needs something under the frame to raise the windshield some from the base of the channel, and to seal it, but am unsure of the best way to do this now after talking to Glassworks.

The last thing I need is another piece of cracked new windshield glass.

[Leif A.]

Re: 1960 Windshield frame installation

Tom,
Just a suggestion not knowing who manufactured the frame strip that you bought. Corvette Rubber has been the "go to" place for all Corvette rubber products for many, many years. Maybe give them a call for some reassurance..

https://corvette-rubber.com/collections/c1-1953-1962/products/w521-56-62-windshield-frame-strip

[Thomas C.]

Re: 1960 Windshield frame installation

Leif, thanks for the reply. It was purchased from Corvette Central who I am pretty sure sources from Corvette Rubber.

[Richard M.]

Re: 1960 Windshield frame installation

Thomas, What was the cause of your previous attempt cracked glass? When you assembled frame to new glass, or assembly to the car?

I have installed many frame/glass assemblies to C1 bodies and always used the CRC rubber body to channel seal successfully. I use 3M Strip Caulk around T-bolt holes(little donuts on each body channel hole) as water blockers.

One note about the rubber. It's profile is a rounded top surface to mate the the lower frame rounded profile. You'd need about 5 boxes of strip caulk to replicate that. Plus the mess if you need to remove it, along with it acting like glue. Some Photos in this informative thread HERE. Post 25.

Me? I wouldn't do that. I once redid a assembly done at a local glass shop. They used pounds strip caulk on glass to frame. Took hours to clean it out and re-do.

To install to body, I just slightly snug the T-bolt nuts under dash and snug up the side post stud nuts to keep the posts from rocking, using 2 orr 3 rubber post shims while checking vertical alignment to door posts.

If I have to add shims I cut slots on the inner sides for stud holes to install them sideways past the studs. T-bolt nuts loosened as needed. Then re-snug all nuts. Note "snug". Do not overtighten, particularly the post studs. When all done I add small "strings" of strip caulk to frame to body gaps. Usually on each side of center as most cars have gaps larger heading towards the doors.

I smooth it out using a small apx 3/16" wide plastic tool I have, wetting with a soapy solution to keep the mess minimized and beaten the look. Then clean any residue from the frame and body with just a soft rag and soapy water. This can get time consuming but gives a much better appearance.

Rich

[Thomas C.]

Re: 1960 Windshield frame installation

Rich, Thanks for your reply. I have actually read all of your posts and I have the document I believe you wrote, but it is good to get confirmation that the use of the rubber channel seal is the way to go. As I said there is definitely a difference of opinion on this subject but I am going to proceed with your suggestions.

I wish I knew why I ran into the issues that I did. Glassworks was very vague on the potential problems I may have had saying just that there has to be the correct amount of "shims" in the right places and everything needs to be lined up correctly. I had the glass crack at different times but never while actually tightening the frame to the body. Once I finished installing the glass into the frame, stopped for lunch, and when I went back to clean it all up, it was cracked just sitting there on the table. Another time I had it installed in the frame and onto the car and all seemed well but again, when I went out later that night to cover the car for the evening the glass was cracked. They both cracked at the curve on the passenger side.

Odd but that's what happened. I will say that I probably did have to tighten some of the bolts more than just snug because if I didn't there was not enough of the t bolt passing through the body and supports to get the nut started in some places. I don't know if I use too much dum dum under the seal around the t bolts or what! Also there would be a large gap between the lower stainless molding and the body around the curve on the passenger side if not tightened up beyond snug. The good news here is that the t bolts installed by Glassworks are longer than the standard bolt.

[Richard M.]

Re: 1960 Windshield frame installation

Hmmm, interesting, pass side twice.

A few questions...

1a - Are your side post tabs original?

1b - If so, Are they broken?

1c - Or did new tabs get installed?

2- where exactly did the 2 cracks occur?

Reason for #2 is if at the top, this is commonly caused by a chip at the edge of the glass by a pick to line up the upper frame nutplate threaded hole for the post to frame screws, or screws too long.

If at the lower portions, possibly:

Broken post tabs,

Overtightened post studs,

Overtightened T-bolts,

Too much caulking,

Prior bodywork at channel surround causing non-parallel mating area,

Soft top too tight, pulling on header. This usually causes frame to pull away from glass, but if glass was urethaned to frame channels, it could find other ways to relieve stress, i.e. crack the glass there,

Glass out of width spec or much too thin. Repro glass is thinner than stock, but I've done many. Maybe it has changed.

Each or several of above, which could cause bending of the lower frame. There are many things that could cause failure. I just want to follow so you don't get a 3rd strike!

Rich

[Thomas C.]

Re: 1960 Windshield frame installation

The side post tabs are original and not broken.

The cracks went the full height of the window from top to bottom.

No prior body work done on the channel.

Soft top was never attached to the frame.

All glass was obtained from Auto City Classics.

Too much caulk, over tightening of bolts, etc., couldn't have been an issue on the one that cracked while sitting on a table before it was ever installed.

It seems there had to be some kind of stress on the glass when installed into the frame that took some time to result in the cracks.

Like I said just trying to prevent any issues that might cause a problem when I install the frame again and based on what Glassworks told me. If this thing cracks again I don't know what I am going to do. The frame has been done since Wednesday and so far no cracks so that is an improvement!