Major setback on installing my windshield

[Keith R.]

I anchored down the windshield T bolts and side post nuts today. Installed the top stainless trim and noticed that the top windshield frame and gasket had pulled away from the upper windshield leaving an eight of an inch or so gap which was a major disappointment as I was hoping to move on to other interior items. The fit of the door posts to the windshield posts was good and the upper trim gap was only about 1/16" on either side. (Incidentally, the upper trim was a real bear to get off once installed but it came off without damage.) There are two rubber shims on either windshield post between the post and body. The windshield is from Pilkington and the windshield gasket is a short gasket from Corvette Rubber which seems to fit very nicely. Any guesses as to what is going on and what I need to do? Could the windshield be cut to the wrong size?

[Troy P.]

Re: Major setback on installing my windshield

My set back was even worse. I tried to bend the glass to fit into the moulding. CRACK! Glass don't bend.

Later I discovered the glass was upside down and that's why it didn't fit so good.

To solve your problem or reduce it you need to fill the lower channel to raise the glass up.

24 years Navy.

[Keith R.]

Re: Major setback on installing my windshield

Thank you Troy. I've read in previous posts from Mike McCagh that many replacement windshields are 1/4" to a 1/2" shorter than originals so I am wondering if that is the problem in my particular case. When sitting on the bench, the windshield seemed to be too short and now the installation suggests that. I'm pretty positive that the upper and lower channels were fitted properly to the side posts so the issue seems to point to the windshield itself. I see that Rich Mozzetta typically uses Auto City Glass and I am wondering if theirs is manufactured by a company other than Pilkington. Your idea of raising the glass by an additional filler strip in the channel may work. I guess that I'm going to have to bite the bullet and start pulling the windshield for disassembly tomorrow.

[Richard M.]

Re: Major setback on installing my windshield

Keith,

I've used Pilkington also and yes they are a bit shorter but worked okay.

I see traces of sealant on the glass to rubber area. What sealant did you use?

I'm trying to figure out when the glass separated. Was it when you tightened the side posts? It almost seems like the side post lower tabs are broken. When you get it apart check back in.

Rich

[Keith R.]

Re: Major setback on installing my windshield

I used 3M Windshield Sealer #08511 which I've had on the shelf for years but it seemed okay. There was a bit of a gap when it was on the bench before I put it on the car but pulling the gasket down a bit from the upper frame covered the gap. That probably should have been a warning sign to me at that point. I think that the gap became pronounced when I tightened the side posts as you suggested. The side tabs were not broken when installed and had not been repaired up to that point. I'll pull it apart and see what the deal is and compare it to the old tinted windshield which fit just fine. I'm thinking that I might have to order another windshield from Auto City Classics unfortunately.

[Pat H.]

Re: Major setback on installing my windshield

I'm having the same problem with my 59. When I reassembled the windshield it was fine until I put it on the car. Now it seams that its separating, so I'll have to remove it come spring time. I used the sealer that CC sell 3M 08509 which is a beading and glazing compound. Its very messy to use and doesn't set up say like a silicone (modern) type adhesive. Prior to taking the car apart, the windshield was fine and didn't pull away from the frame. Is the sealer you mentioned better than the crap I bought from CC? I laso notice that CC is now selling the supposedly correct windshield gasket. Back ordered already. Has anyone had any experience with this supposedly new gasket?

[Keith R.]

Re: Major setback on installing my windshield

I removed the windshield, disassembled it and cleaned up the parts. I compared the height of the new Pilkington windshield with the old one (which never gave me issues) and they both measured exactly 18" tall at the center. Both tabs were intact and were not broken.

I think that part of the problem was the sealant I used or lack thereof. I cleaned out the gasket with acetone and noticed that there wasn't much sealant in the gasket and what was there was rather dry and crumbly. When I first put it together, I applied it sparingly along the outside of the glass by pulling the gasket away from the glass and squeezing it out of the tube per Rich Mozzetta's assembly procedure. The sealant had been on the shelf for many years and perhaps it was too old. I also think that the glass was sitting too far down in the lower u-channel and not far up enough into the top frame.

This time, I think that I will take Mike McCagh's advice and use urethane sealant (3M 08693 - available at NAPA) so that the gasket bonds more to the glass. I am hesitant however, to use it to bond the gasket to the frame as he recommends as it would likely be difficult to disassemble the frame assembly should I need to pull it apart a third time.

[Keith R.]

Re: Major setback on installing my windshield

I saw that CC is now selling the ribbed gasket but I wouldn't trust it unless it was made by Corvette Rubber and is the "short" version. There have been many past forum discussions regarding the gasket being too long and causing rippling and wrinkles in the corners of the windshield.

[Pat H.]

Re: Major setback on installing my windshield

Keith,
I bought a windshield gasket about 20 years ago from on of the Corvette retailers and did not have the winkle issue that you mentioned, I also understand that CC had issues with the product they use to sell. From what I researched there are 2 gasket suppliers, one being Corvette Rubber and Missaukee Molded Rubber in Lake City MI. Apparently, Troy Piles & Rich Mozzetta worked had some conversations with the latter company with regards to the siziing/wrinkle issue. I saw some where that the original rubber measured 122" and the repro was much larger supposedly for installation ease on to the glass. BTW, my windshield came from Auto City Glass 20 years ago.

As for the sealer that Mike mentioned, I'll try that one 3M 08693. I believe that is what the guy that first did my windshied used. If you have to take it apart again, I guess that also another gasket purchase.

[Richard M.]

Re: Major setback on installing my windshield

Keith,
I bought a windshield gasket about 20 years ago from on of the Corvette retailers and did not have the winkle issue that you mentioned, I also understand that CC had issues with the product they use to sell. From what I researched there are 2 gasket suppliers, one being Corvette Rubber and Missaukee Molded Rubber in Lake City MI. Apparently, Troy Piles & Rich Mozzetta worked had some conversations with the latter company with regards to the siziing/wrinkle issue. I saw some where that the original rubber measured 122" and the repro was much larger supposedly for installation ease on to the glass. BTW, my windshield came from Auto City Glass 20 years ago.

As for the sealer that Mike mentioned, I'll try that one 3M 08693. I believe that is what the guy that first did my windshied used. If you have to take it apart again, I guess that also another gasket purchase.

Pat, I always thought they were 2 companies but they are one in the same. MMR is the manufacturer of all CRC rubber.

Tom Hoyer and I worked with them about 3 or 4 years ago. They had a period where they increased the length, then went back shorter to what it is today. Tom and I got these new samples from them and test fit them and all was good. I have a thread in here somewhere that has all of the details. Edit..... Here.

As far as the sealer, yes the urethane is best. I use a NAPA sealer, that I think is just a repackaged 3M urethane product. It can get messy for sure.

Rich

[Patrick T.]

Re: Major setback on installing my windshield

My set back was even worse. I tried to bend the glass to fit into the moulding. CRACK! Glass don't bend.

Later I discovered the glass was upside down and that's why it didn't fit so good.

To solve your problem or reduce it you need to fill the lower channel to raise the glass up.

24 years Navy.

Troy, I share your grief and frustration because that very same thing happened to me when I tried to install a new windshield on my '67.

[Keith R.]

Re: Major setback on installing my windshield

Okay, so I finished putting the windshield assembly back together and this time I used the 3M 08693 gasket adhesive which was relatively easy to use. It has a good medium viscosity so it's not slippery and doesn't get all over the place like the previous stuff I used. I first positioned the gasket on the windshield making sure that the wider lower flap was evenly spaced then I pulled the gasket away from the glass a bit at a time and laid a 1/4" bead of the urethane at the bottom of the gasket channel with a caulk gun. Working time of the product was good and after 24 hours, the gasket is tightly adhered to the glass so hopefully it won't pull away as it did before when I tighten down the bolts. I'm still not quite clear what the purpose of adding or subtracting the rubber post seals is unless it is to adjust the gap between the windshield post and the door post. Right now with two seals in place, the gap was uniform at roughly 3/16"

[Richard M.]

Re: Major setback on installing my windshield

Okay, so I finished putting the windshield assembly back together and this time I used the 3M 08693 gasket adhesive which was relatively easy to use. It has a good medium viscosity so it's not slippery and doesn't get all over the place like the previous stuff I used. I first positioned the gasket on the windshield making sure that the wider lower flap was evenly spaced then I pulled the gasket away from the glass a bit at a time and laid a 1/4" bead of the urethane at the bottom of the gasket channel with a caulk gun. Working time of the product was good and after 24 hours, the gasket is tightly adhered to the glass so hopefully it won't pull away as it did before when I tighten down the bolts. I'm still not quite clear what the purpose of adding or subtracting the rubber post seals is unless it is to adjust the gap between the windshield post and the door post. Right now with two seals in place, the gap was uniform at roughly 3/16"

Keith, It sounds like it'll be a much better result.

When you reinstall the windshield assembly I suggest you add some "telltale" tape on the glass at edge of top frame along the rubber. Attach several strips of masking tape along the glass. Place the tape so it's horizontal edges are right at the edge of the rubber so you don't see glass at the tape joint. When you tighten the T-Bolts and Side Post stud nuts, go slowly and check the tape on the glass as you tighten. If you start to see separation and see glass appearing at your tape markers, stop and investigate.

Shims: I usually start with 2 Side post shims each side. Your 3/16" gap to Door posts may be a little too much and may be part of the reason your glass separated before. You may have to add more post shims if you start to see glass separation when you tighten the nuts. If you do, cut slots along the side of the shims so they can be inserted from the sides after loosening the hardware and slightly raising the posts. This way you don't have to remove the windshield to add them. Also keep in mind that the T-bolt and Side post nuts don't need to be extremely tight. Just snug is best.

I also use this "telltape" tape procedure when I install a soft top so I can see if the header pulls on the frame as I adjust the header latches and vinyl attachment to the header. You can see the tape on the glass below. If I start to see clear glass between the tape and the rubber, I stop and readjust.

[Pat H.]

Re: Major setback on installing my windshield

Thans guys. I just got some great tips from the experts. I also noted that there are some fille strip in the upper windshield frame. I can't remember if I installed them when I did it the last time. If there is any filler strips, what was used? I hate to go back to and order some filler strips that you can buy at HD or Lowes

[Richard M.]

Re: Major setback on installing my windshield

Thans guys. I just got some great tips from the experts. I also noted that there are some fille strip in the upper windshield frame. I can't remember if I installed them when I did it the last time. If there is any filler strips, what was used? I hate to go back to and order some filler strips that you can buy at HD or Lowes

Pat, Any dense foam strip cut to fit the width of the channel will work. I make my own from foam used to seal truck bed caps. Something similar can be purchased at a hardware store, etc. It's apx 3/8"" thick and runs the full length of the channel just inside the nutplates. Pics below.

This foam filler strip in the upper channel is used to fill the gap between the backside of the glass rubber seal and the deep channel. I would think it was used to act as a stop aid when installing the upper channel to the glass/seal. It doesn't have any structural significance so I wouldn't bother taking anything apart to install it.
Rich