Cracked rear glass


Cobraguy

GT Owner
So..as many Rally attendees are aware we experienced around 5-6 rear bulkhead glass fractures at the Rally. Mine failed while on the way to the track on the interstate. Several suggestions have surfaced as to the cause; heat, altitude, and stress are the most common. None of these apply to my case. Possibly those of you that have returned from the Rally with cracked or shattered glass can chime in so maybe we can figure out what the common denominator is here?
And BTW... whatta Rally eh!?!
 

dbk

The Favor Factory™
Staff member
Le Mans 2010 Supporter
Jul 30, 2005
15,187
Metro Detroit
I have inquiries in to figure out what the hell that was all about. It's not like we've never been at altitude or in heat before. So bizarre. At least one cracked on the way before hitting the SLC area.
 

FlagstaffGT

GT Owner
Mark II Lifetime
Is it the inner cabin pane, engine side, middle ( I think it is three layered)?
 

Awsum GT

GT Owner '18
Mark IV Lifetime
Sep 17, 2005
3,985
Carmel & Cntrl Ca
Mine cracked as well on the cruise... I'm thinking it has something to do with aliens
 

davidn

GT Owner
Mar 11, 2007
125
Carrollton,Texas
I have the " Ford GT Window Savers " from cooltech installed in my car....wonder if that would have helped....

http://www.cooltechllc.com/ford-gt-...t-window-savers-torx-socket-not-included.html
 

Mike Mosing

GT Owner
Mark II Lifetime
Aug 9, 2009
970
Florisiana
One possible scenario Inheard was sliding the seat back too hard with the vertical portion of the seat tilted back far enough to hit the glass. In Too Awsomes 's case this looked like it as it started in the driver side lower corner. Bizarre that many.
 

GTJack

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Oct 1, 2006
1,728
Saddlebrooke, MO
I had the same problem at Rally VI in Salt Lake. I had the window savers installed before it happened. Was driving it and hear a loud "pop" behind me, and looked in mirror to see a big crack in the mid-light.
 

Mike Mosing

GT Owner
Mark II Lifetime
Aug 9, 2009
970
Florisiana
Mine cracked as well on the cruise... I'm thinking it has something to do with aliens

Sure that was the window cracking??? :biggrin
 

Spirit

Heritage GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
I have inquiries in to figure out what the hell that was all about. It's not like we've never been at altitude or in heat before. So bizarre. At least one cracked on the way before hitting the SLC area.

Yes, mine cracked while driving to Rally 12 in Cortez Colorado [another high altitude location].
Heard a pop, and could see a “halo” in the rear view mirror [it was night time].
At the time I saw the “halo” I thought it was a reflection of dust on the rear window; however when I got stopped and could check it out, a crack across the bulkhead glass was apparent.
It is the center pane that has cracked; cabin side of glass is smooth NOT CRACKED and the same is true on the engine side of the glass.
Yes, this is a VERY VERY strange phenomenon with so many windows cracking in the same way and in a similar time frame.
I would really like to understand what the cause is so as to avoid having this happen again.
This will be another pricey fix - just what I need.:frown
 

AJB

GT
Mark II Lifetime
Le Mans 2010 Supporter
Jun 28, 2006
2,942
Bloomfield Hills, Michigan
Yes. Mine cracked too. A very clean, horizontal cracking in the center pane. Happened in the early morning driving to UMC in the dark. On the construction areas of I-80.
So perfect and horizontal , it looks like a defroster wire.
Andy (ajb)
 

JWZ

GT Owner
Mark IV Lifetime
Nov 17, 2013
747
Texas
Mine cracked too. At the track. Have subscribed to this thread.
 

GKW05GT

GT Owner
Mark II Lifetime
May 28, 2011
2,754
Fayetteville, Ga.
Can it be age of glass related? There seems to be no common denominator.
 

07XL0027

GT Owner
Mark IV Lifetime
May 20, 2012
1,546
Austin TX
I spoke to Rich Brooks about it at the track. I'm going to paraphrase and I'm sure I'm butchering his response but here it goes. Rich said something like it has to do with how the rear bulkhead was welded together. If the glass was placed to close to a weld, then when the frame flexed over a bump or under strain at the track, the weld could come into contact with the glass and cause it to crack. I'm sure when Rich sees the thread he will explain it much better than I did.


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Mike Mosing

GT Owner
Mark II Lifetime
Aug 9, 2009
970
Florisiana
I spoke to Rich Brooks about it at the track. I'm going to paraphrase and I'm sure I'm butchering his response but here it goes. Rich said something like it has to do with how the rear bulkhead was welded together. If the glass was placed to close to a weld, then when the frame flexed over a bump or under strain at the track, the weld could come into contact with the glass and cause it to crack. I'm sure when Rich sees the thread he will explain it much better than I did.


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I would prefer to blame it on the eclips....:willy:willy
 

ultrasportracing

GT Owner
Aug 31, 2011
488
Perth Western Australia
Hi sounds expensive. I had one made at a local glass manufacturer. for $700. you couldn't tell the difference. Maybe you need to check the welds and a slight buff to diminish the weld fillet protrusion.
 

BIGFOOT

GT Owner
Jan 18, 2012
739
Northeast
Totally bizarre.
I've seen how hot water on frozen glass can melt ice.....
But if you pour cold water on really Hot glass it will crack the glass....

Was there a weird cold hot rain thing ?
 

Special K

GT Owner
Mark IV Lifetime
Aug 23, 2016
1,775
Franklinton, LA
Time seems to be the common denominator, but too many incidents to be a coincidence. I was thinking maybe: over time there was air/moisture penetrating into the laminates and heat/high altitude caused a rapid expansion? I dunno... isn't all glass made to be broken?


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2112

Blue/white 06'
Mark II Lifetime
I have to assume to replace it is either engine out or back-half of the interior coming out.
 

TACHY

GT Owner
Mark II Lifetime
Aug 4, 2006
490
Fort Myers, Florida
Mine is similar: center pane of glass with linear slightly arched crack across the entire width in lower half of the pane. Believe mine probably cracked on the drive to the track; there was a rough patch of highway, but had the stereo up and didn't hear the event.
 

Cobraguy

GT Owner
From the replies so far it appears that in most cases there is one horizontal crack across the glass located in more or less the middle of the panel. Mine is different in that it appears as a "ribbon " of several cracks, 2-3" wide, that runs clear across the pane somewhat diagonally with the individual cracks almost merging in the middle resulting in a horizontal sunburst pattern.It's as if the widow was impacted in the centre but the subsequent sunburst pattern only travelled east and west.
The stretch of pavement on the way to the track was rough but definitely not near as bad as a lot of other surfaces the car has seen in 20,000 m of travel. Perplexing.......