stevepaa

I want ot add a rear wiper to my 92 C2. Anybody know how to drill hole in windshield. Otherwise, I would have to buy a new rear windshield, ~$800. Ouch

C4Russ

You can likely get someone here to trade you. Many don't want a rear wiper.

last toy

Steve, not sure but I think you could have a problem doing that and cause a stress fracture or future stress fracture. The glass is heat tempered from the factory which means that the surface tension is set up to hold the inner glass stress to prevent shattering. I'm relying on my ex-GE engineering days in their lighting business so I could be wrong. You should go to a glass repair shop like Harmon and ask them. They can do all kinds of things with tempered glass these days. They may have tools that can relieve the tension while drilling the hole you need. If they can inject chemicals into a stone chip windshield to stop it from spreading into a crack, they may be able to help you with this. Just make sure you are confortable with their expertise. Good Luck

pete000

I would think it would be much easier just to replace it with an OEM unit.

KirkF

Option A:
Buy the rear wiper.
Attach factory wiring.
Fire Brick through rear window
Make insurance claim.

Option B:
Get rear window with wiper shipped from junkyard.

Option C: (as per info from the internet.)
Drilling Tempered Glass - Not Recommended

Tempered glass can be drilled, however, breakage may run as high as 80% to 90% depending upon the degree of temper in the glass. We do not recommend trying to drill tempered glass.

The manufacturing process of making tempered glass results in the glass having a large amount of stress between various portions of the glass. The stress points might look much like a piece of wood containing lots of "knots", however, there is no outward appearance to indicate the hidden stress. Highly tempered glass will often crack at the stress points near the hole. Since the amount of hidden stress increases with the degree of temper, the success rate of drilling tempered glass reduces with the increase in glass temper.

There is no way to know the amount of temper in a piece of tempered glass, so there is no way to evaluate the amount of risk involved in trying to drill it. Therefore, we DO NOT RECOMMEND attempting to drill tempered glass.



Kirk

last toy

Key Kirk, thanks. You made me feel good that my aging mind still retains some useful knowledge. Love your Option A thta has to be the best . By the way, what kind of spoiler do you have on your C4. I am thinking about doing the same to mine but not sure which is best. I was hoping there would be one on the market that could be integrated with the exiating factory spoiler to avoid replacing the engine hood.

KirkF

Don,

When the topic came up I was curious enough about it myself to go digging. Its something I never thought of before. I suspect they form the rear glass, then drill the hole then temper it. Several online resources claimed they could cut glass and temper the glass on the spot.

My wing was on the car when I bought it. Its an RS 3.8 adjustable rear wing. It completely replaces the motorized wing. Very easy to install, just 4 bolts and unplug your motor wiring. (And then add a jumper wire to keep the car happy)

I am often of two minds on it. Sometimes I like it, but sometimes I think it looks to large for the back of the car. (Maybe more suitable to the widebody cars)

http://www.gt-racing.com/catalog/default.htm

Shows it under 911 wings.

Kirk

last toy

Thanks for the info and site. Not cheap are they. Before i go there, I need to do a suspension mod this spring, lower the car and get it all aligned. I always did like the RS 3.8 wing. Guess it depends on how aggressive you want the car to look. Not crazy about the turbo wing, but like the subtle GT 3 wing. But don't think that will fit a 964. Thanks

stevepaa

Thanks, Kirk and Don. I won't drill.

Now, if I can just pull a brick out of the chimney.

KirkF

On a 'similar' topic, I have to change my front windshield soon.

The layers between the glass are separating in one corner, and the plastic safetyshield between the glass is turning milky white. (6" so far and expanding). I have never seen anything like it before.

Can I borrow that brick once you get it chipped out?

Kirk

last toy

$500 for a replacement, I got s star crack from a stone right at the seal between the windshield and dashboard. Hate to replace it because the window and seals are near perfect. Hope my shop can do a good job. I think it was always there as a glass dink and started to fracture the first cold morning when I hit the defroster. And I thought kids were expensive.