Most people have heard of SID Syndrome - Sudden Infant Death Syndrome. Some have heard of SBGD syndrome, but probably not by that name, Sudden Back Glass Death Syndrome.

One day I was standing under a shade tree talking to a guy whose pickup was also there in the shade. He was standing behind the truck with his back to it. I was facing him. I just happened to be looking at the back window of the truck when suddenly, with a pop, it developed a million cracks all in a split second.

I'd heard of this happening for no apparent reason, but never dreamed I'd be looking straight at one when it happened. Nor had I dreamed that I'd walk out and find the same development on my '65 Valiant this morning.

Does anybody know - if I get a used back glass, is it anything more than a crap shoot knowing whether it might do the same thing? That is, are old, reinstalled windows more likely to do it?

Does this also happen with camera lens.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Don't be looking at my car's glass!
I may have a used BW, any know the years, I think it's all 63-65 Valiants, Hardtops & Sedans.
DD

There are two kinds of safety glass used in cars. Laminated glass is two sheets of glass with a layer of soft plastic in between. It is marked "AS-1" and is used in windshields. Tempered glass is one single layer of glass that has been specially heat treated such that it contains specific kinds of internal stresses. This is done so that if it breaks, it breaks into relatively safe granules rather than jagged, dangerous shards. It is used in side and rear glass and is marked "AS-2". Occasionally, the internal stresses of a piece of tempered glass will combine with other factors (ambient temperature, for instance) and the glass will spontaneously break as you describe. The exact manner and speed with which the glass is tempered can make this kind of failure more likely. Chrysler had a problem with this on certain of their North American-market minivan backglasses, 1991-1995. But outside of that, it will happen from time to time on a random basis (or perhaps Doc is right and your secret superpower is the ability to break glass with nothing more than your gaze), there's no relationship between age and likelihood of spontaneous breakage. What will increase this likelihood is any kind of localised stress on the glass. If any part of the body "fence" or gasket is unduly pinching, squeezing or bearing against the glass, the odds of spontaneous breakage go way up, so it pays to pay very careful attention during the R&R.

Interchange on that glass is indeed '63-'65 Valiant (only) sedan and hardtop.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

my car has tempered glass on the sides and laminated on the front and rear windshields. I do recall some people waking up to find out that their side glasses was broken (especially on central areas of the country where the absence of water produces extreme temp ranges during the day) I had 8 sedans and 4 hardtops and the only time I had a broken glass was during a mountain road trip, a truck picked up a stone with it's tire's threads and throwed it at my windshield and it broke. Laminated, so no really big deal.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

It's also more likely if the shade tree you are parked under happens to contain black walnuts.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

That's pretty cool. Laminated has pretty much been confined (by custom, not by law) to front windshields in the US and Europe for quite a few years. It's thinner and less costly. But, back in the '50s, laminated-all-around was common. There were some articles in the early 1960s claiming significant safety advantages to laminated over tempered, and there might be some practical merit to that argument.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

No. I'm much prettier than that.

So it's essentially a built-in feature, especially in some cases. There was an obvious stress point at the bottom edge from which a sort of pattern went a ways.

I knew there was stress in treated glass and, in the case of house glass which I've had a lot of experience with, wondered how they get away with it. (Of course some glass is inherently stronger than others, based on its composition.) The answer would seem to be more how long they get away with it. Virtually forever in most cases.

Thanks

also it might be have been stressed by some under weatherstripping rust, maybe. One thing I always do before installing my glasses (i do it myself, since stupid kids at automotive glass shops down here doesn't know how to deal with real weatherstripping instead of jap cars glued on glasses, and they end up damaging the rubber or breaking the winshield or leaving it leaking like my nose right now...) is drop the glass in the lip w/o the rubber and check for evenness of spacing or potentially stress points like a corner or curve that doesn't follow the body shape or stuff like that.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Not bloody likely if I don't start having better luck getting this thing long haul worthy. I'll check the place where I got my 10" drums, altho I'm not sure I'd trust them pulling one out. Car-Part.com shows a couple about 90 miles away, believe it or not.

Thanks

Good advice. I won't tell you about the first time I installed a back glass in 1963. It was on a 1962 Dart that had been hit in the rear. Car was nice. Installation was not. I did great on the windshield, but the back glass was a horror story to match my first timer skill.

Thanks

my first installation sucked on the front winshield! we can team up I broke the piece of weatherstripping 3 times. when I finally got to install it right, leaked like niagara falls.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

You must have just about drowned before you got out of the car!

Little different circumstances but it happened to me once too. while I was working at the dealership. Middle of winter, about -10*F outside, about an hour before quitting time, (I was on the noon to 9PM shift) my co worker and I decided to pull our vehicles in to thaw and warm up before the drive home. Him 1st, then I went and got my truck. AS SOON as I got inside the building and shut it off I got out and by the time I walked to the back of the truck the back window in my cap shattered to a million pieces. Loud pop when it went too. 79 D 100 shortbed.