Chronic Windshield Cracking---96 Super Stock Camaro

Rusty Davenport · 12-14-2007, 09:50 AM

I have replaced my windshield on two occassions for cracks. Body flex ???? I don't think so---if that were the case the vertical body struts to the roof on each side of the windshield would be bent or twisted plus the roll cage has to offer some degree of structural help. The break always occurs from right to left starting at the passenger side. Anybody care to comment ????

SSDiv6 · 12-14-2007, 10:28 AM

Quote:

Originally Posted by Rusty Davenport

I have replaced my windshield on two occassions for cracks. Body flex ???? I don't think so---if that were the case the vertical body struts to the roof on each side of the windshield would be bent or twisted plus the roll cage has to offer some degree of structural help. The break always occurs from right to left starting at the passenger side. Anybody care to comment ????

The struts will not show signs of distortion, they will distort along with the roof duirng the launch only. You need to revisit the frame connectors, how they were made and welded and how the cage structure was welded to the frames. Do you have a roll bar or cage?

njk53 · 12-14-2007, 10:44 AM

Sheet metal has some resiliance and can flex and move back to it's original position so as long as you do not pass a theshold where it will begin to bend and stay bent. You may not think so but I'll bet the windshield frame is flexing more than you think.
I had a brand new 2001 Camaro as a rental car in Phoenix (130 miles on the odometer) that sat in the 112 degree heat for most of the day. When I came out to leave the windshield was cracked. A technician from the GM Proving Grounds said that windshield cracking could happen from time to time because it wasn't installed from the factory properly and coupled with the thermal action on the sheet metal made it flex enough to crack it. Make sure the dimensions of the windshield and the widshield frame allow for ample tolerance. Make sure the window frame is free of burrs, nicks, spot weld residue, and old windshield sealant that can pinch the windshield when the body flexes. Also, use a good quality automotive urethane sealer when you install the new windshield.

1slowformula · 12-20-2007, 11:04 PM

rusty is it a hardtop or T-top car? I have seen a lot of guys crack windshield in T-top cars and not show any flex in the sheetmetal, btu I have also seen it the other way around too, dimpled sheetmetal but no cracks, but the dimpled sheetmetal cars all dimpled on the driver side...

SSDiv6 · 12-20-2007, 11:23 PM

Quote:

Originally Posted by 1slowformula

rusty is it a hardtop or T-top car? I have seen a lot of guys crack windshield in T-top cars and not show any flex in the sheetmetal, btu I have also seen it the other way around too, dimpled sheetmetal but no cracks, but the dimpled sheetmetal cars all dimpled on the driver side...

...and the reason why I welded all the seams while building the car.

Philip Saran · 12-21-2007, 01:18 AM

Back to the rental car....if all the windows were closed tight in 112 degree weather the heat
build up alone can be enough to crack the windshield (supposedly the weak point).
I used to live in Palm Springs (116 degrees in June coming out of class's) YOU left the
windows down a bit.

Gordon Boven (DECON) · 12-21-2007, 03:47 AM

njk53 has just about covered it. But, You mite want to weld a piece of metal from the cage to the pillar on both sides. This should help the twisting of the body on the cage.

Dave Casey · 12-21-2007, 06:03 PM

Rusty,
As a racer and auto glass shop owner/operator for 30 + years, here are my suggestions.

The windshield will flex some with the body of the car, more than you may think. It should not break.

Remove the broken windshield and look for a tight spot(s),any place that the windshield(or molding that goes around it) is tight to the body or trim.

Look to see if that the amount of urethane sealant that is around the windshield is got some depth to it. You don't want to have the urethane thin, or squezed out , as the windshield will be almost resting on the metal and the chances of a stress crack greatly increase.

There are some urethanes that are more rigid than others, i would suggest using a less rigid one and make sure that when you install the new windshield that it doesn't get pushed to far into the sealant. The factories use differant methods to keep the windshield from being pushed to far into the urethane. The most common one is to use foam tape 1/4 - 5/16 thick to keep the windshield at the correct hight.The windshield in your car has a three sided molding and the top side of the molding should keep the hight of the top of the windshield correct, but the lower section of the windshield could get pushed in to low, so use some foam on the bottom and sides.

Hope that helps, Dave Casey, 413 734 5277 days at my shop if you have any questions

Ed Wright · 12-21-2007, 09:01 PM

This makes me a lttle nervous. I've bracket raced my '96 Fiebird for three years (going faster than it will now in SS/JA) with no problems, and mine is a T top car. How often does your Camaro crack them?

76 RACER · 12-22-2007, 01:01 PM

I would say the way to stop it is to use a 5/16 tape kit to set the shield. Then back seal it with Urethane. That is really the right way to do a shield. The old school way. Now days a mobil installer comes out and just barely scrapes the pinch weld enough so he can primer it and run a bead of Urethane to set the glass. Make sure no moulding clips are touching the glass on the top or the sides and make sure the rubber stops on the bottom of the glass are there.

12-14-2007, 09:50 AM	#1
Rusty Davenport Senior Member Join Date: Jun 2005 Location: Nashville N.C. Posts: 506 Likes: 4 Liked 101 Times in 27 Posts	Chronic Windshield Cracking---96 Super Stock Camaro I have replaced my windshield on two occassions for cracks. Body flex ???? I don't think so---if that were the case the vertical body struts to the roof on each side of the windshield would be bent or twisted plus the roll cage has to offer some degree of structural help. The break always occurs from right to left starting at the passenger side. Anybody care to comment ????

12-14-2007, 10:44 AM	#3
njk53 Senior Member Join Date: Jul 2007 Location: East China, MI Posts: 504 Likes: 0 Liked 0 Times in 0 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro Sheet metal has some resiliance and can flex and move back to it's original position so as long as you do not pass a theshold where it will begin to bend and stay bent. You may not think so but I'll bet the windshield frame is flexing more than you think. I had a brand new 2001 Camaro as a rental car in Phoenix (130 miles on the odometer) that sat in the 112 degree heat for most of the day. When I came out to leave the windshield was cracked. A technician from the GM Proving Grounds said that windshield cracking could happen from time to time because it wasn't installed from the factory properly and coupled with the thermal action on the sheet metal made it flex enough to crack it. Make sure the dimensions of the windshield and the widshield frame allow for ample tolerance. Make sure the window frame is free of burrs, nicks, spot weld residue, and old windshield sealant that can pinch the windshield when the body flexes. Also, use a good quality automotive urethane sealer when you install the new windshield.

12-20-2007, 11:04 PM	#4
1slowformula Junior Member Join Date: Dec 2007 Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro rusty is it a hardtop or T-top car? I have seen a lot of guys crack windshield in T-top cars and not show any flex in the sheetmetal, btu I have also seen it the other way around too, dimpled sheetmetal but no cracks, but the dimpled sheetmetal cars all dimpled on the driver side...

12-21-2007, 01:18 AM	#6
Philip Saran Senior Member Join Date: Oct 2006 Location: Parker, CO. Posts: 728 Likes: 163 Liked 14 Times in 11 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro Back to the rental car....if all the windows were closed tight in 112 degree weather the heat build up alone can be enough to crack the windshield (supposedly the weak point). I used to live in Palm Springs (116 degrees in June coming out of class's) YOU left the windows down a bit. __________________ Phil Saran Parker, Colorado

12-21-2007, 03:47 AM	#7
Gordon Boven (DECON) Junior Member Join Date: Sep 2007 Location: Boise ID Posts: 20 Likes: 0 Liked 0 Times in 0 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro njk53 has just about covered it. But, You mite want to weld a piece of metal from the cage to the pillar on both sides. This should help the twisting of the body on the cage. __________________ Gordon Boven 670 S/ST

12-21-2007, 06:03 PM	#8
Dave Casey VIP Member Join Date: Dec 2002 Location: Hampden, MA Posts: 1,198 Likes: 233 Liked 769 Times in 162 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro Rusty, As a racer and auto glass shop owner/operator for 30 + years, here are my suggestions. The windshield will flex some with the body of the car, more than you may think. It should not break. Remove the broken windshield and look for a tight spot(s),any place that the windshield(or molding that goes around it) is tight to the body or trim. Look to see if that the amount of urethane sealant that is around the windshield is got some depth to it. You don't want to have the urethane thin, or squezed out , as the windshield will be almost resting on the metal and the chances of a stress crack greatly increase. There are some urethanes that are more rigid than others, i would suggest using a less rigid one and make sure that when you install the new windshield that it doesn't get pushed to far into the sealant. The factories use differant methods to keep the windshield from being pushed to far into the urethane. The most common one is to use foam tape 1/4 - 5/16 thick to keep the windshield at the correct hight.The windshield in your car has a three sided molding and the top side of the molding should keep the hight of the top of the windshield correct, but the lower section of the windshield could get pushed in to low, so use some foam on the bottom and sides. Hope that helps, Dave Casey, 413 734 5277 days at my shop if you have any questions __________________ Dave Casey 1330 STK

12-21-2007, 09:01 PM	#9
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro This makes me a lttle nervous. I've bracket raced my '96 Fiebird for three years (going faster than it will now in SS/JA) with no problems, and mine is a T top car. How often does your Camaro crack them? __________________ Ed Wright 4156 SS/JA

12-22-2007, 01:01 PM	#10
76 RACER Member Join Date: Mar 2007 Posts: 247 Likes: 0 Liked 0 Times in 0 Posts	Re: Chronic Windshield Cracking---96 Super Stock Camaro I would say the way to stop it is to use a 5/16 tape kit to set the shield. Then back seal it with Urethane. That is really the right way to do a shield. The old school way. Now days a mobil installer comes out and just barely scrapes the pinch weld enough so he can primer it and run a bead of Urethane to set the glass. Make sure no moulding clips are touching the glass on the top or the sides and make sure the rubber stops on the bottom of the glass are there. Last edited by 76 RACER; 12-22-2007 at 04:07 PM.