Windshield frame problem

[RexNZ59]

Hi everyone, I'm new to this forum and I have 2 questions that have bugged me for the last 8 years. When I originally restored my '75 Convertible, I removed the windshield and surrounding stainless mouldings for repair and replacement. Underneath the top stainless header moulding I found rubber foam soaked in a type of 'gunky' bituman product. I guess that it would stop water running through into the interior. I asked around and was told (1) leave it empty, and (2) fill it with RTV. I filled it with RTV and when it went off, the water tracked over it and ran into the interior. I can't find any information on what was actually used in production and down here we tend to have inclement weather so we can go out in the fine and end up wet. The cars must have been quite waterproof originally,so if anybody out there has any ideas I would be grateful. I could probably use tar but it may not be the correct smell for the year

Question 2. I've replaced the windshield twice since I've had my car and both times when I've replaced all the mouldings, there's been a gap at the top between the windshield and moulding. Advice was to 'just fill it with black RTV'. I'm due to replace it again in the next few days. I read somewhere a few months back that the windshield didn't actually sit against the frame at the top. Does anyone know what was used to gap it. Blocks of rubber? wood? maybe a strip of rubber. Was there a specific depth? I know that someone out there has the answer to these questions, and like I said in my introduction, if I'd known about this website I would have been a part of it from the start Thanks you guys.

 

[hotshotzny]

Hi everyone, I'm new to this forum and I have 2 questions that have bugged me for the last 8 years. When I originally restored my '75 Convertible, I removed the windshield and surrounding stainless mouldings for repair and replacement. Underneath the top stainless header moulding I found rubber foam soaked in a type of 'gunky' bituman product. I guess that it would stop water running through into the interior. I asked around and was told (1) leave it empty, and (2) fill it with RTV. I filled it with RTV and when it went off, the water tracked over it and ran into the interior. I can't find any information on what was actually used in production and down here we tend to have inclement weather so we can go out in the fine and end up wet. The cars must have been quite waterproof originally,so if anybody out there has any ideas I would be grateful. I could probably use tar but it may not be the correct smell for the year

Question 2. I've replaced the windshield twice since I've had my car and both times when I've replaced all the mouldings, there's been a gap at the top between the windshield and moulding. Advice was to 'just fill it with black RTV'. I'm due to replace it again in the next few days. I read somewhere a few months back that the windshield didn't actually sit against the frame at the top. Does anyone know what was used to gap it. Blocks of rubber? wood? maybe a strip of rubber. Was there a specific depth? I know that someone out there has the answer to these questions, and like I said in my introduction, if I'd known about this website I would have been a part of it from the start Thanks you guys.

i looked and looked and i cant find the stuff on here but i remember as a kid when my dad had his VW shop helping him replace windshields and when i replaced a rear window in my pickup years back he had this tube if rubber.. i think it was called live rubber..... but last i saw it was 1990..god im gettin old:eyerole..... if you are thinkin of a tar like substance this has got to be the same crap.... if i know my father he may still have it in one of the cabinets in the old garage...or he will know what its called

this is the closest thing i have found so far
http://www.acehardware.com/sm-perma...t-permatex-flowable-silicone--pi-1419004.html

 

[RexNZ59]

i looked and looked and i cant find the stuff on here but i remember as a kid when my dad had his VW shop helping him replace windshields and when i replaced a rear window in my pickup years back he had this tube if rubber.. i think it was called live rubber..... but last i saw it was 1990..god im gettin old:eyerole..... if you are thinkin of a tar like substance this has got to be the same crap.... if i know my father he may still have it in one of the cabinets in the old garage...or he will know what its called

this is the closest thing i have found so far
http://www.acehardware.com/sm-perma...t-permatex-flowable-silicone--pi-1419004.html

Thanks for that... I'll have a look at that site now. See.... I'd never heard of that

 

[hotshotzny]

they probably took the stuff i used off the market because it caused cancer knowing my luck

 

[RexNZ59]

they probably took the stuff i used off the market because it caused cancer knowing my luck

Doesn't everything I had a look and couldn't really tell a lot about it... hey, it's somethin

 

[6880 Mike]

Rex, Do you have the '75 assembly instruction manual (AIM)? The AIM shows the stock windshield installation and lists the sealers used in the installation, amounts to be used, etc. It also shows blocks used to position the glass if they were used.

The gooey stuff you removed was factory sealant. An auto glass replacement shop ought to have today's equivalent of the sealant used 30 years ago.

 

[RexNZ59]

Rex, Do you have the '75 assembly instruction manual (AIM)? The AIM shows the stock windshield installation and lists the sealers used in the installation, amounts to be used, etc. It also shows blocks used to position the glass if they were used.

The gooey stuff you removed was factory sealant. An auto glass replacement shop ought to have today's equivalent of the sealant used 30 years ago.

Hi Mike, thanks for that information, I've just got back from working on my car all day, as you do I've not heard of that manual but sounds like something I should have. Do you know if it's available or would it be easier to liase with you on what information I'm after (don't want to be a bother) Does the manual talk about the sealant in the windshield or is that just something that you know about. The glass shops that I use seem to stock a lot of silicones etc but i've never seen this stuff... it must come in a steel container or somesuch... Thanks for your help and any other information you can give me

 

[RexNZ59]

Rex, Do you have the '75 assembly instruction manual (AIM)? The AIM shows the stock windshield installation and lists the sealers used in the installation, amounts to be used, etc. It also shows blocks used to position the glass if they were used.

The gooey stuff you removed was factory sealant. An auto glass replacement shop ought to have today's equivalent of the sealant used 30 years ago.

Hi Mike , found the AIM on Amazon and am just going to order it as soon as I can find a couple more books to keep the postage reasonable Should receive it in about three weeks and the cars got to be ready in twohnoes so if you can ;help with anything I sure would appreciate it.

 

[6880 Mike]

Skip Amazon unless the price is near $22. All the Corvette aftermarket providers carry the AIMs in the $22 range. The best deal comes with a three ring binder to put it in (AIM pages are punched for 3-ring binders). You can find them on ebay.

 

[GTR1999]

You're going to want to use urethane over silicone.

 

[RexNZ59]

Skip Amazon unless the price is near $22. All the Corvette aftermarket providers carry the AIMs in the $22 range. The best deal comes with a three ring binder to put it in (AIM pages are punched for 3-ring binders). You can find them on ebay.

Covette America have them for21.50 with no binder... Corvette Central for 24.95 with binder ....... apart from the binder I guess a manual is a manual. Are some better than others

 

[RexNZ59]

You're going to want to use urethane over silicone.

Thanks Gary...... I've tried silicone and with urethane that would definately make for a stronger bond ...... I think if I go back to the original way of doing it ( which I haven't tried) that would be the way to go.....

 

[3dale1]

You're going to want to use urethane over silicone.

Yep, stay away from the silicone.

When I did my windshield, I used 3M Butyl windshield tape (which is original). Come in a 25" roll of 1/4, 5/16, or 3/8 diameters.

Took that a step further by applying a bead of urethane over the TOP of the butyl that the windshield would sit on, figuring I'd get a better, stronger seal; yet I did not apply the urethane between the butyl tape and the windshield frame itself in case I ever needed to remove the windshield again. Worked fine, no leaks.

Much easier to separate the windshield from the frame without breaking it if you use the tape--cut between the tape and the frame. Using the urethane will make it a lot tougher to remove the windshield if you have to cut it out between the glass and the frame.

 

[JohnZ]

When I did my windshield, I used 3M Butyl windshield tape (which is original).

Just to clarify, GM never used butyl tape for windshield or backlite installations - it won't pass the required MVSS windshield retention requirements in a frontal impact, and doesn't have the shear strength to improve body torsional rigidity. Factory installations used Thiokol pumpable 2-component adhesive starting in 1968, which was later replaced by the same urethane adhesive that's used today.