My rear window project

[Hnichols]

Hi everybody,
Thought I'd share my experience of my rear window ordeal -- er, installation. Thanks to all here who helped with advice.

Edit: Since posting I removed the window and installed it a third time. Here are some things I learned along the way. If I had known them before I started it would have been a much easier project. Maybe they'll help future generations ...

1. Before tearing into the rear window, make sure your leaks aren't caused by the water intake holes, otherwise known as roof vents (on the coupe). Even when filled with new foam insulation they let in an astonishing amount of water. I can only guess that their point was to instill humility in us coupe owners towards our targa brethren. I put a strip of duct tape across the holes that looks unobtrusive. Fortunately my car is silver.
2. Don't reuse old trim if it's bent. Not worth the trouble.
3. Even though Wayne's instructions (rightly) tell you to PLACE the rear window in top first, you should should seat the window from the bottom. (Porschenut -- see comments -- is right!) If you do that, there's no need for a second string.
4. You don't need to cut the plug for the defroster wires; it will pass through the hole between the parcel shelf and the engine compartment if you pull up the rubber sleeve first. (Duh!)
5. A good technique that saves your headliner is to press a thin putty knife (2" wide or so) against the headliner as you draw the string over it. The seal will fall over the knife, and then you drop the knife straight down. The string cuts across the edge of the knife, not the headliner. Wish I had thought of this the first two times I installed the thing. My poor headliner took a beating.
6. Don't remove the black dum-dum putty that is in the corners (see bugmeat's comment below). It probably was put there at the factory, not by the PO to compensate for a half-assed window install.
7. A good auto glass shop can put a bead of sealant between the seal and the glass if the seal isn't tight. No need to do it all over if the window was positioned correctly.

First, here's what the window looked like before. A thoroughly botched job; the trim in the lower corners was totally mangled. Why was I surprised it leaked?!?





My greatest fear, naturally, that years of damp insulation would have resulted in rust. Good news is that there was none -- thank God for galvanzation!

[Hnichols]

In the 101 Projects book, Wayne wisely devotes a separate section on removal -- knowing that people have a tendency to rush the job and make costly mistakes. At the same time it is not difficult -- certainly not the three stars of difficulty he assigns the task. Installation, however, is another story ...



Removing the defroster wires is a bit of a pain. The two ground wires connect to a bolt behind the fuel filter in the engine compartment. The others connect to a plug near the rear fuse box. I had to cut off the plug to get the wires out through the hole in the interior.


As you can see, the headliner took a beating during the previous installation.

[Hnichols]

If your headliner is in good shape, and your careful, I don't see any reason why it should get damaged during installation. If, on the other hand, it looks like mine, you do what you can (I used some black duct tape in some places to discourage tearing.)

Threading in the defroster wires for the new seal requires surgical patience and care. Cutting holes into the rubber is also a bit tricky. But overall I found this aspect of the job pretty straightforward.

Installing the trim I found to be one of the more challenging parts of this project. Your hands will be sore for a weak. The plastic trim in the '88 and '89s is much harder to install because it has two "barbs," one on the inside, one on the outside. The aluminum trim hooks only on the outside.

[Hnichols]

Installing the rope: For the bottom end of the window, I used two ropes. That's because you don't have any room to work the seal if the rope pulls out without pulling the seal over the lip. The reserve rope saved me from starting over.

I also put a piece of rope at the corners to prevent the upper part of the seal from curling under.


Installation took a couple of tries. Make sure the window is really pushed up when you start (you start at the tip of the window, not the bottom).

What you DON'T want to happen after installation: the trim comes unseated. Then you have to start over. I made the mistake of using old trim and bending it into shape. If the old trim, buy new trim. Trust me, it's worth the money if it spares you a second installation.

[Hnichols]

The final result: generally pretty good, I think. The lower corners are the trickiest. The inside part of the trim isn't flush with the seal -- I don't even know that is possible!


This shot of the beautiful profile of the 911 explains why the rear window can be so tricky. At the bottom the window is higher than the frame; at the top it goes under. The seal and the trim have to undergo some contortions to follow the lines of the car.


I'm glad this job is behind me!

[porschenut]

Originally Posted by Hnichols

The plastic trim in the '88 and '89s

Is it '89 too? I thought the plastic trim was one year only, '88.

Another question - are you sure it's easier to start pulling the rope at the top instead of starting at the bottom? It seems to me that if you start at the bottom, it would make sure the window isn't too low. If you start at the top, it might not be far up enough to draw the seal in once you get to the bottom.

[Hnichols]

You might be right: they may have gone back to aluminum in '89. That would explain why I wasn't able to get the plastic trim from the dealer.

As for starting from the top: I took this on authority from what I read; I didn't try it from the bottom. It may be that it would require too much pressure on the bottom if you were to start there (?).

[tirwin]

Hnichols,

That looks way better than it looked than when you first started. Congratulations on a fantastic job!

[Hnichols]

tirwin: thanks for the compliment -- but it turned out to be not so fantastic. It flunked the water test. I don't know how the devil the water got in, but it did.
I beat the trim flush with the seal in the lower corners, so now it looks nearly perfect. But, to be honest, I'm not that hopeful. Man, I did everything by the book -- I was SO careful. I have no idea what I did wrong -- if anything.

[bugmeat]

When you removed the window was there any dum-dum (sealing putty) in the lower corners? My car had a strip in each corner, and as far as I can tell it was there since new. I'm thinking it is necessary to fill up/seal any gaps that are there.

[Hnichols]

Good question! Yes, there was (black) putty there, but I removed it. I figured it was put there by the PO to compensate for a poor installation. And it didn't prevent leaks either.
There are gaps in the corners, but I would be surprised if that stuff is there from the factory. Could be wrong, of course.

I think the problem is that for some reason the lower end of the glass sunk in -- it didn't do that on the previous installation. Maybe has to do with the "north/south" positioning (?) or maybe the seal has only a few tries in it.
Today I brought it to a guy who has done alot of old car windows, VWs mostly. We'll see if he can make it work.

[Hnichols]

For anyone who might read this thread: Turns out that the window seal is NOT leaking. The water is coming -- actually pouring -- through the roof vents. Makes me feel better about my window installation. On the other hand, I can't see how stuffing foam in those holes is going to make them waterproof. On the other hand, they're completely open (the original foam has completely disintegrated).
So we move on to another phase in this saga. Hopefully this part won't be as arduous as the window replacement. ...

[porschenut]

I think the purpose of the foam is to keep out bats and centipedes, not necessarily water.

[911-32]

FYI, 89s don't have any trim, metal or plastic. They use the 964 seal for both front and rear screens (and also 964 size glass). Hence, the screens on an 89 look a little more flush.