Exploding Rear Window - another victim
12-15-2007, 03:32 PM
#16
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I'm no expert but I think the speed warning is for the action of opening the sunroof at speeds over 50 mph, not having it open at higher speed. My guess is the preasure created as you crack it open could rip the headliner loose (heck it peels off by itself sometimes!)
12-15-2007, 03:42 PM
#17
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I've also seen a guy use a sledge hammer on a Camaro back glass and nearly kill himself trying to break it. The hammer just keep bouncing back until he hit it near a corner and it finally exploded. The strength is in the center of the glass. I've also broken one just taping the edge with a small screwdriver. The edge is the weakest point.
So tempered glass is very strong and can be very flexible, but it can also explode unexpectedly due to many different factors.
Just my $0.02.
So tempered glass is very strong and can be very flexible, but it can also explode unexpectedly due to many different factors.
Just my $0.02.
So, short story long, my thoughts on the rear window failures in the 993 make me wonder if some of these cars rear window framings, or apertures have either a sharp metal protrusion, sliver or burr that is near the glass edge when installed (under the rubber seal)? The car twists and forces a sharp feature into the edge of the glass? Just a theory. Or, is the sheet metal aperture a little on the small side therefore pinching the window? Dont know really.
12-15-2007, 08:59 PM
#20
I'm Still Jenny
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I've read many post on the exploding rear window, and I having some experience in the glass industry, I thought I might be of some help, although my back glass is plastic.
The back glass exploding problem is not just with 993's or Porsche's IMO. I've seen tempered glass (Back glasses, door glasses ect...) break on many different cars for no apparent reason. We sold and replaced many in Ford, Chevy, Dodge, Toyota, and just about all the mfgs. I've also seen a guy use a sledge hammer on a Camaro back glass and nearly kill himself trying to break it. The hammer just keep bouncing back until he hit it near a corner and it finally exploded. We replaced more Camaro / Firebird Back Glasses than any (talk about a problem, these cars had a major issue with the glass breaking). The strength is in the center of the glass. I've also broken one just taping the edge with a small screwdriver. I cringe anytime I see someone near the edge of a door glass with a metal object. The edge is the weakest point. I've also seen a guy take a door glass and throw it like a Frisbee across a parking lot and it was only scratched. And I've also taken a back glass from a pickup and set it on a table and nearly bent it over 90deg. and it didn't break. And I've seen a guy walk out of our shop in the winter, going from 70 deg. to say 15 deg. with a new door glass under his arm and it exploded before he could get to his car.
So tempered glass is very strong and can be very flexible, but it can also explode unexpectedly due to many different factors.
Just my $0.02.
The back glass exploding problem is not just with 993's or Porsche's IMO. I've seen tempered glass (Back glasses, door glasses ect...) break on many different cars for no apparent reason. We sold and replaced many in Ford, Chevy, Dodge, Toyota, and just about all the mfgs. I've also seen a guy use a sledge hammer on a Camaro back glass and nearly kill himself trying to break it. The hammer just keep bouncing back until he hit it near a corner and it finally exploded. We replaced more Camaro / Firebird Back Glasses than any (talk about a problem, these cars had a major issue with the glass breaking). The strength is in the center of the glass. I've also broken one just taping the edge with a small screwdriver. I cringe anytime I see someone near the edge of a door glass with a metal object. The edge is the weakest point. I've also seen a guy take a door glass and throw it like a Frisbee across a parking lot and it was only scratched. And I've also taken a back glass from a pickup and set it on a table and nearly bent it over 90deg. and it didn't break. And I've seen a guy walk out of our shop in the winter, going from 70 deg. to say 15 deg. with a new door glass under his arm and it exploded before he could get to his car.
So tempered glass is very strong and can be very flexible, but it can also explode unexpectedly due to many different factors.
Just my $0.02.
12-15-2007, 11:39 PM
#21
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I used to hang around a body shop a lot and I've seen the same thing happen...Beat the crap out of one piece of glass trying to get it out and it won't break for anything. Let a hand tool slip and lightly tap a piece you want to stay whole and it crumbles on contact.
I truly believe that there is a Murphy's Law kind of negative correlation between breakage and the need to preserve the glass...The more you need the glass, the less likely it is to resist breakage.
12-16-2007, 04:33 PM
#22
Alright one more glass story.
I started working for a auto glass shop during college in 1989. The big craze back then was the sliding back glass in pickups. We would remove the old rubber set glass, mark make, model, and year, and put them in the corner for later. Some customers would come in with one section of the slider broken and think you could just replace one section, when told they needed a whole new unit ($85 to 90 for a new one) they would want a regular glass reinstalled. We usually gave them a used one and charged $40 to install it. It was first day on the job for me, cocky 19 year old, thought I knew everything and really knew nothing, but eager just to work on cars. My supervisor with the mullet and the dip of Skoal in his mouth in his mid 30's, thought I always needed to pay my dues and learn a lesson (a ton of funny stories with this guy). Yes it's Arkansas so all you thoughts on this guy are correct. Well, maybe not with his sister!
So he ask me to get one of these back glasses out of the corner for a certain model P/U and I start digging through the stack, once, then twice, still can't find it, and on the third time, you guessed it; KKAAAPOWWW I lightly bounced one on the concrete floor and it shattered everywhere. I didn't at this time know these were free and of course Johnny wasn't going to let me know about it either. He had me on egg shells all week long. I thought I was for sure fired. He had the owner come talk to me and it was the biggest joke that week for everyone. I remember I was so worried the boss would never let me touch another one of his classic cars again. See he was a Barrett Jackson kind of collector, and I was his grunt even before I got the job. I cleaned and polished his classics at his home on the weekends and after school. Bob was the man!
I sure do have some funny stories from those years, but learned a lot from those rednecks. From the trucking companies to the body shops to the car lots, I got to see some of the best work to the worst rebuilds ever. You sure can learn a lot from the car business. Once it's in your blood it stays.
I started working for a auto glass shop during college in 1989. The big craze back then was the sliding back glass in pickups. We would remove the old rubber set glass, mark make, model, and year, and put them in the corner for later. Some customers would come in with one section of the slider broken and think you could just replace one section, when told they needed a whole new unit ($85 to 90 for a new one) they would want a regular glass reinstalled. We usually gave them a used one and charged $40 to install it. It was first day on the job for me, cocky 19 year old, thought I knew everything and really knew nothing, but eager just to work on cars. My supervisor with the mullet and the dip of Skoal in his mouth in his mid 30's, thought I always needed to pay my dues and learn a lesson (a ton of funny stories with this guy). Yes it's Arkansas so all you thoughts on this guy are correct. Well, maybe not with his sister!
So he ask me to get one of these back glasses out of the corner for a certain model P/U and I start digging through the stack, once, then twice, still can't find it, and on the third time, you guessed it; KKAAAPOWWW I lightly bounced one on the concrete floor and it shattered everywhere. I didn't at this time know these were free and of course Johnny wasn't going to let me know about it either. He had me on egg shells all week long. I thought I was for sure fired. He had the owner come talk to me and it was the biggest joke that week for everyone. I remember I was so worried the boss would never let me touch another one of his classic cars again. See he was a Barrett Jackson kind of collector, and I was his grunt even before I got the job. I cleaned and polished his classics at his home on the weekends and after school. Bob was the man!
I sure do have some funny stories from those years, but learned a lot from those rednecks. From the trucking companies to the body shops to the car lots, I got to see some of the best work to the worst rebuilds ever. You sure can learn a lot from the car business. Once it's in your blood it stays.
12-16-2007, 10:31 PM
#27
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Speaking of windows that are hard to break, thought you guys would enjoy a demonstration:
http://www.youtube.com/watch?v=PuySmopuwL4
Looks like Chris could have given them some lessons!!
http://www.youtube.com/watch?v=PuySmopuwL4
Looks like Chris could have given them some lessons!!
09-19-2023, 08:55 AM
#30
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Exploding rear window repair
Many users have described the exploding rear window phenomenon in their 993’s. It happened to me the other day for no apparent reason. Now the problem is getting it replaced. I’ve called every window glass shop with in a 50 mile radius. They all refuse to do the job. I live in northeast New York State. Does any one know who will do this job? The local Porsche dealer can get the glass and gave me the number of the shop they use. They refused the job too