BrickBoard Archives
The files contained in this listing have been automatically archived from the active forums. Because the vast majority of posts are now in one place, this archive is considered legacy. You should use the SEARCH feature OR choose your topic and select date tabs within the forum you choose.
Rear window goes bye-bye...[200/1989] posted by Kyle Sullivan on
Friday, 29 October 1999, at 12:49 p.m.
Hello-
I had a pleasant surprise yesterday on the ride to work. I was on Route 95 and my rear window all of a sudden shattered. A sniper? No...
Upon the loud noise of stress, I peered back to see a completely shattered window, but no holes. Soon small pieces started to fall out of the window puzzel onto the road behind me. I then pulled over and pushed the window into my back seat. I was luck enough to find someone to put a new one last night. Cost: $300, the best price I could find.
My question for our helpful experts here is: What the heck caused it? All I can recall is that I cracked open the side-rear windows a bit about 5 minutes before it happened. Is this related?
The guy from the glass shop said that sometimes a shorted rear-defroster relay will blow out the rear window. I don't recall my rear-defroster staying on a long time. Has anyone heard of this? Are there any issues with the rear windows?
-Kyle Sullivan
Re: I think it's called "Cabin Pop" or ??...[200/1989] posted by Tom Irwin on
Friday, 29 October 1999, at 1:33 p.m.
I heard about this once from a Volvo guy.
Under certain circumstances, with the rear windows partially opened, a resonant, oscillating pressure change or 'POP' will develop at the lower end of highway speed.
Sometimes, if you hit it just right, you can blow out the rear glass!
Swear to God!
There are baffles and traps in the body that are suppose to disperse that phenomenon as well as the ear drum popping that might otherwise occur in the passenger compartment when a door is slammed.
Sometimes it just don't work I guess.
You can hear this thing develop in almost any car under the circumstances listed above. It sounds kind of like a cross between a "Whump-Whump-Whump" and a "Thwacketa-Thwacketa-Thwacketa" (Take THAT to your Service Advisor)
Anyway, Sorry.
Tom
Tom Irwin 95 960, 94 940 Los Angeles, CA
Re: Rear window goes bye-bye...[200/1989] posted by Kyle Sullivan on
Friday, 29 October 1999, at 5:56 p.m.
Thanks for the responses. Very interesting.
I guess this phenomena seldom occurs.
-Kyle Sullivan
'89 240DL 143k miles
'88 740 Turbo 105k miles
Re: Rear window goes bye-bye...[200/1989] posted by Zee on
Saturday, 30 October 1999, at 8:15 p.m.
Kyle,
Adding to the discussion is the nature of the buytl-rubber rope sealant used on older models that didn't have the rubber gasket on the glass. From my recent research into how to install a windshield on my '84GL, I learned that this rope sealant has a very low ability to hold fast a windshield. It is not even used now since the mid-1980's, having given way to the urethane that "glues" the glass to the body.
This urethane has such a higher holding strength, engineers even count on it now for structural integrity for safety in case of a collision.
Not so, with the rope sealant. The only purpose for this now is as a "dam" or backing to one type of the urethane. A second type of the urethane is called "high viscosity" or "high volume" and will stand thick enough on the pinchweld to accept the edge of the glass without needing the "dam".
The specific difficulty with the old rope sealant that has bearing on your condition, is its tendency to dry out and begin cracking with old age. It is not unheard of that a glass pops out with a good slam of the door.
Finally, the use of these new urethanes on installation jobs requires a curing time of about 24 hours before the car should be moved. Until the sealant is set, this pop out can occur.
Zee. Easton, PA '86 244DL, 154K, all synthetic, turbo swaybars, Tociko shocks / '84 244GL (junkyard project car)