Having problems with windshield upgrade to 964 style.

[scarceller]

I just changed my 84 911 windshield and decided to purchase the 964 and the 911 (with trim) seals both OEM Factory Porsche seals. The glass is new PPG aftermarket.

First, the PPG glass is slightly smaller all around than the factory Sigla glass by 5/16", all glass is not the same so be very careful with aftermarket windshields.

Then I inspected and measured both seals carefully and the bottom line is that the 964 seal uses larger glass. I don't have 964 glass to measure but can tell from inspecting the 2 seals that the 964 seal would require glass about 9mm larger all around, meaning 18mm larger in height and width. The 964 seal allows the glass to come much closer to the body, meaning the distance from the edge of the glass to the outside edge of the seal (the edge that touches and seals against the body) is 6mm on the 964 seal. But on the 911 seal it's 15mm! way different. Bottom line is that the 964 seal requires the 964 glass. I'm not saying others haven't had success using the 964 seal with 911 glass but if you do you'll never get that setup to seal properly.

Another area that's different is the channel where you put the rope into. The channel in the 911 is 10mm but in the 964 is 14mm this implies that the 964 must have had more metal tab in the frame than the 911 cars. I'm sure this won't be a show stopper but it implies the 964 seal and glass in the 911 car won't install as tightly as it would in the 964.

If I did it again I certainly would have spent more time sourcing the glass and to insure the glass was as close as possible in size to the factory Sigla window.

I now have a spare factory 964 seal. Maybe someday I'll find factory 964 glass cheap, if I do I'll redo the install.

[abisel]

After all the talk regarding what glass and what seal to use on what year cars, is this the consensus?

• All cars with the 10mm pinch weld flange were designed for the early 911 glass and seal with the aluminum/plastic trim. These cars will accept the 964 glass and seal but the fit may be a little loose because of the seal dimensions. These cars will also accept the 993 glass and 2-piece seal but again, the fit may be a little loose because the glued area between glass and inner seal is smaller.

• All cars with the 15mm pinch weld flange will not accept the earlier 911 glass and seal. These cars will accept the 964 glass and seal as well as the 993 glass and 2-piece seal.

• The same hold true for the rear back-glass on coupes.

The only issue with the 993 glass in the early 911 is the location of the VIN plate. At least up to a certain year, the VIN plate is on the A-pillar whereas the 993 glass has an open area at the bottom for the VIN plate.

Now, how do the 996 glass/seal and the 997 glass/seal fit into the picture? Or do we care?

[onboost]

Originally Posted by abisel

now, how do the 996 glass/seal and the 997 glass/seal fit into the picture? Or do we care?

not !!

[brcorp]

Subscribed

[abisel]

I though I would share a few pictures of my test fit of a 964 windshield and 964 factory rubber into my RSR project.

Here's the roof skin ready to install. It is a later model skin with the 15mm pinch weld flange.



Since I don't have the magic windshield template that the factory uses to check windshield opening dimensions prior to welding the roof skin into place, I just clamped the roof skin in place and then installed the windshield to check the fit.



Also, I installed the windshield without any assistance or rubber lube. I was worried it would be a PIA, but not so. A large braided pull cord, slaping the glass with the an open hand and light taps with a piece of wood and rubber mallet on the rubber only. The corners and A-piller required caution so as not to tear the rubber.

















Bottom line: With the windshield installed, I was able to find one place where the pinch weld sheet metal needs some work. The bottom right corner of the roof frame support and the bottom right corner of the roof skin. There is a slight twist in this area. But hey, using the windshield as a template works fine.

[fat cab]

great project your working on! looking forward to seeing it around town..

[DG624]

I did the same thing with my 86 Carrera...the only problem I have noticed is a slight pulling away from the windshield by the weatherstrip at the corners of the windshield. I can adjust this by pulling the weatherstrip down and toward the car body. Have you noticed this also?

[scarceller]

Am I correct that you need both the 964 Glass and the 964 Rubber to install into a 84-89? In other words you can't use 84-89 glass with 964 rubber?

I'm under the assumption that the 964 glass is slightly larger than the 84-89 glass.

[abisel]

DG624: I did not notice any pulling away of the rubber from the glass. Maybe your pinch weld is bent a little in those areas. Make sure the pinch weld is 90 degrees to the body.

scarceller: Yes, you would need both a 964 glass and 964 rubber to install in pre-89 cars with a pinch weld of 10mm. The 964 has a 15mm pinch weld. Thus, the 964 glass is slightly smaller than the pre-89 glass because of the larger pinch weld and the 964 rubber has a deeper channel for the 15mm pinch weld.

There has also been some questions regarding using urethane adhesive on 964 windshields/rubber. The factory work shop manual says to use the adhesive. Both in the channel for the glass and in the corner of the pinch weld/body all around the opening. Not much, but enough to seal.

[abisel]

Here are pages from the 964 shop manual:

[DG624]

I can't adjust the mounting trim without removing the glass and weatherstrip...its is not worth it. The weatherstrip seems to shrink back from the car body slightly and leaves a depression along the edge of the weatherstrip. I can adjust it by pulling it back toward the windshield. If this means that the windshield is lose it may be worth it to adjust it tighter by removing the glass again. Why do the instructions say to cut the weatherstrip?

[abisel]

Me thinks the reason the instructions say to cut the old rubber seal is because it was originally glued in place.

[HiWind]

I have a 993 and a 993 glass which had to come out due to the same old rust infront of the a-pillar/on cowl issue ... I see PET/Pelican only lists 2 rubber pieces for the front screen - wondering what to do if the aluminium/hard plastic frame moulded onto the windscreen is broken in parts?

Its not too bad as it seems the frame only provides a slot for the outer trim to clip into .. right?
So can the glass stick to the inner rubber with just the right adhesive?

If not, is there anywhere I can buy that moulded frame piece?

thanks all!

Matt

[Rodsrsr]

I tried this mod as well and the 964 glass didnt work, it was simply too small. I had the exact problem that Sal described.

[Cobalt]

Not sure if this helps after so many years of this thread running but I recently purchased a later style carrera windshield with antenna for $225. It was Sekurit which I believe was factory. Unfortunately I needed it for my 964 so it did not fit. from what i can tell the 911 3.2 windshield was 3/8" smaller on all 4 sides than the 964 windshield. The best I could find for the 964 was Sekurit for $425 but the car came with Sigla from the factory which run around $1200. I will say that the shape of the windshield is identical other than being smaller all around. The 964 also has the black band across the bottom.

Not sure why the 964 windshield would be an improvement for rust. The 964's still suffered from rust in the lower right hand corner.

[Rodsrsr]

Okay I had to rethink this as it was a few years back. The 964 windshield was too large for the 911 opening. I remember because the installer could barely get it to fit, and when he did the rubber gasket didnt hold. I've heard that it may or may not work but usually will not fit. In my case it definitely did not work.

[DG624]

I used the 964 windshield in my 86 Carrera with the 964 weatherstrip. It has been OK but like I said the weatherstrip tends to shrink back away from the glass at the corners of the windshield. It seems OK except for that and it is smoother without the metal weatherstrip insert. It looks good too.

CIMG0184_zps97b93259.jpg Photo by DAVEG-01 | Photobucket