Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

[Roger W.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

This is a very good discussion. I was planning to assemble my 59 windshield in the near future with rubber that I purchased from CC last year. It will be interesting to see what the final outcome of the rubber length will be. Thanks to all who have worked on this project.

[Richard M.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Those corners look nice. Get that slack out and I think you have a winner. Were you able to take an overall measurement?

Mine came today and I'm going to start "playing" with it tonight.......... Pictures later.

Tom

Hi Tom, No I didn't have time earlier but I'll try to get a measurement tomorrow. I'm also going to measure the glass circumference. This one I have here on this '61 is noticeably thicker than the last one I got from Auto City Glass last year for a '59. Theirs is thinner than the old replacement that was in that car. This one for the '61 is marked PPG and I think came it from OEM Glass several years ago.

I'm eager to see how that new rubber works for yours. Is your glass new, and where is it from?

Rich

[Dan B.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

I have assembled a few of these using NOS GM weatherstrips, they always fit tight and perfect. As far as functionality, had some premature cracking on the outer face only (Cosmetics) but they otherwise looked as original. I don't see why CRC is having such a problem withthe repros. The Glass is the glass, it has not changed in length. Get A tape measure, measure it, then make one to specs. Am I missing something here?? Sorry for the rant, but too many poorly fitting parts out there. Dan

[Richard M.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

I have assembled a few of these using NOS GM weatherstrips, they always fit tight and perfect. As far as functionality, had some premature cracking on the outer face only (Cosmetics) but they otherwise looked as original. I don't see why CRC is having such a problem withthe repros. The Glass is the glass, it has not changed in length. Get A tape measure, measure it, then make one to specs. Am I missing something here?? Sorry for the rant, but too many poorly fitting parts out there. Dan

Dan, Total agreement with your comments. How this happens is always a mystery, but to err is human I guess. Poor fit is a commonality, unfortunate as it is, but we have no choice sometimes. Frustrating. Believe me, I know. We all know.

But I understand somewhat why CRC changed it. They had complaints it was too tight, so they changed it. In actuality, the glass in fact has changed. Thickness, overall circumference, height, etc. I've seen several variations, maybe not big differences, but a little here and there may make a difference.

In hindsight Mike feels they tried to help a few (over tight)cases that maybe were not that critical. He now knows he kinda' broke it when wasn't broke. But he's fixing it again now. I'm just happy that we have a supplier like CRC that's willing to work with us to resolve this. In the past I've had several other vendors just blow me off with no regard for customer service. If it's not high volume, high margin, high profit, some just don't care.

My top vendors, past and present, equally for excellent CS policies are: Zip Corvette, Dewitt's, Paragon, Grossmullers, Dave Sokolowski Parts, my local NAPA, and now CRC. If you want my list of the WORST companies that I've totally removed from doing business with, feel free to send me a PM.

Rich

[Dan B.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

I recently purchased a CRC W/S which I was going to use to replace the NOS GM one (someday) after cracks developed on the exterior radius. Car sits covered in the garage most of the time, so I have to believe this is due to a chemical breakdown of the original rubber due to age since it was obviously not exposure. Just curious, do you know what the correct spec is for the windshield radius around ?? I'd like to check the CRC part I have and get the revised smaller one so I don't end up with "The Battle of the Bulge".

[Richard M.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Dan, I do not have the circumference spec, if there is one. The rubber cannot be exactly the same circumference as the glas, becasue if it was, the dashpad corners would still wrinkle. In order to eliminate wrinkles there, the rubber must be stretched to overcome the inside radius "tucking" which causes the wrinkle.

If your rubber was purchased within the last 2 or 3 years, it is too long and will absolutely bulge at the top when you get the lower section stretched, as my photos showed above.

Tom Hoyer and I are getting the first new version samples. Tom has his now but hasn't checked in yet with results. I expect to get mine next week. If you can wait a week or so, we'll have results on the new rubber fit. If it works well, I recommend you contact Mike at CRC and swap yours out.

Rich

[Dan B.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Thanks for the reply. Might I suggest using the original specs of an NOS GM Weatherstrip. I know there are still several floating around out there. Maybe someone could lend theirs to the cause because I know they DID fit properly. I am confident that with those measurements and new improved CRC rubber an excellent result should be achievable. Dan

[Richard M.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Dan I don't think a NOS GM rubber today is the same overall length as it was when it was originally made. The rubber must shrink with time. I say this because I had one a year or so ago, and it was SO tight, it wouldn't stay on the glass. It had a orange Ecklers label on the blue/white paper envelope dated around mid/late 80's IIRC. It kept slipping off the glass it was so tight. I was a bit worried it was so tight that it was going to break the glass at the sweeping curves on the sides.

So I left it out in the sun for hours, tied with rope across fence posts to stretch it out. After it stretched I was able to get it to stay put over the glass. I built the frame/glass assembly and left it on the bench overnight. Installed it on the car next day. It looked great, but as mentioned in a previous post somewhere, a few days later it split at the bond seam.

Rich

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

A quick update. I received the new gasket on Friday. I want to put a bit more detailed response together (the holiday responsibilities seem to be cutting into my Corvette time), but I have a few minutes now so a brief summary..........

I had three issues with the two older gaskets I had tried over the last few weeks. wrinkling along the inside radius of the flap, the inside flap too short not covering windshield post and excess length.

I'm very pleased to say that the new gasket has addressed each issue. I have taken some measurements and pictures and will post them later, but I can say that the new gasket was about 3" shorter then the longest old gasket I was trying.

Right now I have the upper and lower parts of the frame mounted to the windshield. I hope to have some time later today to get the posts installed and survey the whole installation.

Updates to follow............

Tom

[Richard M.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

That is great news Tom! 3" is right on the money based on my tests of the longer one the other day in my post above......I had that 3" amount of slack when it fit better. Perfect!

I feel quite good now about Mike's modifications.

Rich

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Ok, here goes.......... this gets kind of long, but........

We know the following; wrinkles along inside flap, flap not covering bottom of windshield post, excess length.

With the new "prototype" gasket from CRC, I first measured it and compared it to my existing two gaskets. Results:
CRC prototype; Overall, 67 1/2" with a flap length of 65 5/8"
Gasket #1; Overall, 69" with a flap length of 66 1/2"
Gasket #2; Overall, 70 1/4" with a flap length of 67 5/8"
(Keep in mind these lengths are approx. as I tried not to stretch the gasket. They were all done the same way so the delta between the measurements should be accurate.)
So this shows that the prototype gasket is almost 3" shorter then the longest one I have (Gasket #2)

I found the mid point of the top section and started installing the gasket from the top center towards each end. When I got to the ends, you could see where the shorter length came into play as the gasket was now fairly taught between the ends. Starting at one end and working towards the other in about 8" increments, the gasket installed easily and was tight around the entire perimeter of the windshield. At this point it was immediately noticeable that there were NO wrinkles and the flap section would easily cover the bottom of the windshield post.

Assembling the windshield frame is pretty straight forward (since I have done this about a dozen times over the last few weeks..........). I rubbed some bar soap along the gasket edge to help the parts slide on. I first installed the bottom, then the top and then each side. Everything seems to fit well but another issue seems to have cropped up. I noticed that the gasket is not fully seated in the upright portion of the windshield post. I can push it in with my fingers, but it slips right back to where it was. It is almost like the windshield isn't long enough to hold the gasket in the post.

The reason I had to replace the gasket is that when I got the car, the windshield was broken. I ordered a new windshield form Auto City and it was damaged during shipping so I just happen to have two windshields laying outside that I could compare. One original, one reproduction. Since the one is pretty well busted up on one end, I only have one good end to work with. I laid the new one inside the original and lined up the bottom edge. Sure enough, the reproduction one does not follow the contour of the original in the windshield post area and at one point is about 1/4" smaller. They both line up top and bottom as well as the end, but the problem is at its max in the middle of the upright section. I believe that if the new windshield followed the contour of the original, the gasket would be fully seated in the windshield post as it should be.

While I was messing with the two windshields I also took some thickness measurements. I picked two points to measure, one near the corner radius and one along the top edge. The corner of the original was nominally 0.230" and the new one was nominally 0.220. About a 0.010" difference. The top of the original measured 0.240" and the new one was 0.220". There appears to be some thickness change in the original and the new one is fairly consistent. Again, I wasn't taking all out absolute measurements, just a few points for comparison but it would be safe to say that the newer windshield is between 0.010 - 0.020" thinner in some areas.

Summarizing, I believe that the gasket issue has been addressed by CRC, but more data from other installations would be helpful before they lock down the dimension. Like I told Mike, a sample of one doesn't mean much if you plan on making hundreds or thousands. Hopefully Mike and a few others will have similar results. I do need to talk to Mike about the area where the top section is joined to the bottom section as the one I have has been trimmed a bit aggressively in this area. You'll have this with prototypes.........

A few pictures starting with the identified problem areas to follow.

Tom

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

A few more pics showing flap gap and measuring

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Some more showing new gasket flap to post overlap and NO WRINKLES!

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Last batch, measuring glass

[Thomas H.]

Re: Corvette Rubber Company - C1 1956 to 1962 Windshield Rubber Weatherstrip Issues

Just kidding, a couple more. One showing gasket during mid-install, where the stretching begins.