rich5962

FYI....a reprint of what I posted over on the NCRS site tonight...

Several of us have had issues with the windshield rubber leaving wrinkles in both inside corners where they lay over the dashpad, as well as gaps in the lower section where it's supposed to fit over the chrome flanges of the bottom horizontal section of the windshield posts.

This morning I spoke with Mike at CRC and discovered why some of us have had these problems. Coincidentally, he told me he just got off the phone with Corvette Central over the exact same issue earlier in the morning. The problem is that the rubber is too long. Different glass circumferences can also cause variations in the installation of the rubber. Some may fit better than others.

Mike said that a few years ago they were getting many complaints that the rubber was too tight going onto the glass.The original length was 132" then and there were complaints is was too tight for some installers. At that time they decided to increase the overall length of the rubber, by as much as 8".

He said they receive the extruded rubber pieces from their supplier and bond and fabricate the final product in-house. The extrusion is a "straight" type and has no bends in the corners.

When I told him about my latest difficulties, and similar issues that Tom has had in the in the above thread, and that the wrinkles re-appear after using a heat gun, he offered to have me return the wrinkled rubber from mine here, and also the replacement I have coming from my supplier if that does not fit properly either. He said they have "shorter" versions of the rubber and will swap them out no charge. Mike was very understanding and helpful with this issue. He knows the C1 windshield is a difficult one and wants to make our jobs easier.

I then explained that many of us here, as well as on other technical Corvette forums, have had issues. He then offered that if any of you feel that your windshield rubber from CRC is too long and will cause wrinkles, he told me to have you contact him directly to help resolve this problem. He explained that CRC wants to provide a properly fitting product and wants to work with customers to resolve issues. He sounded quite sincere and concerned about the problems we've been having and wants to help us fix them.

Additionally, Mike said they are going to rethink their fabrication process and try to come up with a new overall length of the rubber to correct the problems on future product.

Mike can be reached there at CRC at 231-839-7725.

Corvette Rubber Parts
Missaukee Molded Rubber, Inc.
6400 W Blue Rd
Lake City, MI 49651

http://www.mmri-crc.com/
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Rich
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p.s.
Reference thread on NCRS site.....
http://www.ncrs.org/forums/showthrea...Gasket-Overlap

mike coletta

Thanks for all that Rich. I just threw 2 brand new ones away because they fit like crap. Waaayyyy to long. They both came from Grossmuellers (Corvette Central parts). I had an old one in the back room, and used it. It fits like a glove.

Mike Coletta

wmf62

i can't imagine that the circumference of a windshield varies by as much as 8".... no way....



Bill

rich5962

Bill, I had the same reaction, but he explained that their earlier rubber had to be stretched much onto the glass. When they increased the rubber 8" it then didn't need to be stretched so much over the glass. In fact, it fits too loosely now.... which is the problem and why the tabs don't meet and why the wrinkles appear.

wmf62

makes me want to consider reusing my old rubber, which fits perfectly, when i replace the windshield....
Bill

Frankie the Fink

This must have started just a few years back - my windshield was replaced on the '61 in 2009 and the rubber along the dash pad is PERFECT; it was purchased from Corvette Central brand new at the time...

I also can't imagine why tight fitting rubber would prompt somebody to add an add'l 8" to its length - way overkill for a minor problem...

rich5962

Mike told me they changed the length 2+ years ago, and 3 years ago I put one in a '59 and had to stretch it out quite a bit to get it on the glass. End result was perfect for me. CC buys from CRC, along with just about all of the vendors, Zip included.

The problem according to Mike was that there were some folks breaking their glass trying to get them on. I agree they obviously added too much and "overcorrected", and now have to go back some the other way.

One thing that makes me feel good about this issue is that as a vendor, and as a wholesaler at that, Mike took some serious time to talk to me about it. Many other wholesale vendors wouldn't even call me back when I had some "constructive" info for them to consider.

I always considerd CRC products top on my list. I've used their rubber on '50's to '70's cars I've worked on and never had a problem. They're standing behind it which is a good thing.

C-1 Generation 2

I replaced mine in 2009 with new Pilkington glass after getting the 62 painted. I bought the weather stripping from CC. No sign of wrinkles on mine.

rich5962

Bill, It'll probably be a mess when you remove it, or it may split at the joints at the base of the posts. The other issue is that the new glass from Auto City Classic Glass, made by Pilkington, is a tad bit thinner and dimentionally different from original glass. This difference may give you rubber trouble.

BTW, if you ever find a NOS GM w/s rubber, throw it out. I tried using one a few years ago. Really had to stretch that one out due to shrinkage over time. Got it on, assembled frame, back on the car, and it looked great.

3 days later I walked by, and saw the big split in the seam at the base of the post. Re-do.

rich5962

Mike at CRC is sending a new version of the rubber for me to test out on a '61 windshield I have here. Tom H is getting one also so we'll compare notes and let you know how it looks.

Rich

rich5962

Update......Tom H. installed the new shorter version rubber he got from Mike at CRC today for his '58 windshield and it fit much better. No wrinkles and the tabs over the bottom flange of the w/s posts cover properly. This new version is 3" shorter than the previous version.

I did a few experiments the other day with the new longer version I had shipped before all this contact work happened. I got it to fit perfect at the corners and tabs when I stretched it out, leaving a 3" slack at the top.

I think it's going to work. More info when I get my shorter version this week........so I can get this '61 back together for even more assembly fun.

Rich

thoyer

As Rich said, I completed my assessment of the new gasket. Here are the gory details that I put up on the NCRS board yesterday

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















Here is a link to some more pics on photobucket
http://s21.photobucket.com/user/tmh4...?sort=3&page=1

rich5962

I finally got time to install the new CRC rubber seal from Mike. See this post for pics etc.

Fits perfectly.

http://forums.corvetteforum.com/c1-a...-tutorial.html

VG30jtin

Good morning Thoyer,

Did you every find a solution to your fit issue....ie: "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."

I seem to be having the exact same issue with a Pilkington glass and seal...both supplied from Zip.

Thanks so much, Chip

VG30jtin

Good morning Rich,

I responded to Thoyer's issue and thought that maybe you might have a suggestion. His issue's: " 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."

I also have wrinkling and not enough coverage from the lower inside flap

Thanks so much. Looking forward to your reply

Chip

rich5962

It may be that you didn't stretch the seal enough at the lower corners to cover the lower tabs in the posts. Doing this also eliminates the horizontal wrinkles in the corners at the dashpad. This is based on you having a seal from CRC made recently, long beyond the time when they had the longer version previously discussed.

This stretching will add some looseness along the posts and along the upper horizontal channel, but you can cheat that by pushing the seal from side to side towards center at the top joint. The sealant will help to keep it in place.

The other issues regarding the looseness along the vertical joints at the posts is quite common. The design geometry of this joint area promotes this issue. You could add additional sealer there afterwards to help hold the seal in place.

Rich

VG30jtin

Rich,

Thanks so much. You make sense. I'll disassemble today and give it another shot