Rear window question, what am I getting myself into?

[DonDavis]

So, I can be the worst at starting a project and saying “Oh, while I’m in there I’ll do this extra thing too…”

When I started my interior last summer, I planned on taking about 2 months to get it done. Lots of things came up and wham, bam here we are 10 months later. One of the holdups was the rust I discovered. Nothing too major but it needed to be addressed before proceeding. I talked to a couple shops and will most likely use the same place that did Joeaska’s backdate (Patrick Motorsports).

The rear window gasket has an issue that bugs me and I also wonder about its watertight integrity. It's on both upper corners and it turns down. If I remove the rear window and quarter windows, it makes access a lot easier for the shop to do their work. I can then address the gasket issue.




My big question is… how difficult is the R/R of the rear window? My headliner is ok but could eventually warrant replacing so do I do the headliner while the rear window is out? That would mean R/R the windshield as well. A bit of a slippery slope, IYKWIM!

Comments?
Thoughts?
Complaints?

[Noel]

The photos make it look like the seal is just folded under itself. Have you tried using a putty knife wrapped in duct tape to try to pop it out? I bet if you just run it along the seal toward the corner, it will pop right out.

[dd74]

I have the same problem as Don on my front windshield. No matter what I do, the gasket/seal folds under. The seal itself looks to be in good shape. The only thing I can think of is some sort of deformity in a part of the seal that I can't see.

As for the headliner, decide quickly what you want to do while the rear windshield is out. Also, I believe, the front windshield has to come out. So, yes, it would probably be a good "while you're in there" project.

[DonDavis]

Not driving my car the last few months has been tough. Our spring weather has been untypically nice. It's usually hitting the 100's by now and yesterday it was 77. I need to get this pig back on the road.

I was hoping someone that has removed their rear window would offer their experience. I think I read where Wayne was involved with one and he said it was a real PITA.

Anyone?
Bueller?

[widebody911]

Try warming it up and using a popsicle stick

[no substitute]

The wires to the heating element amplify the difficulty considerably. Other than fitting the wiring in the channel of the gasket, it is quite easy. I haven't seen the tucking on the back before, front yes. Perhaps a bit of rubber cement after popping out the corners. It looks like there is sufficient rubber there, odd that it tucks under.

[DonDavis]

No sub,
What about the headliner? Does that get hosed easily? Can the window be removed/replaced without "opening a can of worms"?

And Thom, you are talking about my window gasket, right?
I'll get it a shot.

[no substitute]

I had no problems with the headliner at all. If yours is good and you're careful not to accidentally tear it (unlikely), I'd leave it alone for now. I hear headliners are somewhat difficult, and my understanding is that you must remove both front and rear windows. If the headliner ain't broke...
The only can of worms you'll open with the rear window is the wiring to the heating element. You will in all likelihood employ colorful language. It is however, doable by the home mechanic. I suspect a second set of hands would be helpful. If the radius of the rubber in the corners matches the curve of the sheetmetal (not under tension when pulled out), I'd give the "Barge rubber cement under the corners" thing a try.

[GeorgeK]

Don, That is typical in my experience. If the seal is new enough and not the source of the folding (an old seal shrinks enough to do just that), try and find some "dum dum" paste or string. The dealer has that.
The openings on the shell are sometimes a wee bit too large and allow the seal to fold in. Nothing really helps other than putting whatever is necessary there. On my 930 the factory did put some such string in the corners to keep the seal in place.

[no substitute]

Almost forgot, the metal trim strip can be difficult to get to match the window contour.

[Harlan Chinn]

Use nothing sharp while probing around under the rubber seals, and if you end up removing the seals do your self a favor and don't cut all the way through and nick any of the body work as someone may have done before if your car has ever had either windshield replaced. You may find a rust spot at those areas and would be a good time to attend to those before they rust through. Both winshields and side trim must be removed to replace the headliner.
If your car has a two stage defroster, you'll have two pair of wires that will trace around the rubber seal and exit at two spots on the lower driverside corner. If you remove the seal cutting from the right corners you can preserve the proper locations in the old seal for you to reference when you buy the new seal and learn that none of these exit holes exist. Set the wires into the new seal following the same path as the old, set the windshield into the seal and get a rope ready to reinstall this sub-assembly back into the opening.

[Jim Sims]

Using the term "dum dum" for the filler material to add to the body at windshield and rear glass corner areas (my '76 came from the factory with filler in all the lower corners, front and back) only produced dumb stares at auto supply stores and dealerships. What you want is 3M Seam Sealer Caulking Strip (part number 08578). It is available at NAPA (although they may have to order it in overnight from their warehouse). The NAPA Part number is MMM08578 and they charge $13.99 a box; a box is plenty to install windshield and rear glass. Also, use only Porsche OEM glass gaskets; the reproduction gaskets do not fit properly.



Jim

[Hetmann]

I've had my rear window out a couple of times. Taking it out ia a snap. Just push from the inside and out it comes. Getting it back in is a bear. You need to put a rope in the seal and work it in. Two man job (at least) with lots of persuasion to get it just right. I would recommend letting a glass shop put it back in for you.

[jazzbass]

Originally posted by Hetmann
I've had my rear window out a couple of times. Taking it out ia a snap. Just push from the inside and out it comes. Getting it back in is a bear. You need to put a rope in the seal and work it in. Two man job (at least) with lots of persuasion to get it just right. I would recommend letting a glass shop put it back in for you.

What he said. Easy to get out, PITA to get back in. If you can pay someone to do it for you, do it. I'm having a hard time finding someone who'll do it for a reasonable price. Last estimate was $300.

If you R&R don't bend the trim in any way, shape or form. Cut as much rubber away as necessary to remove the trim without disturbing it, unless you want to buy new trim (ask me how I know). And ditto on the advise to buy on Porsche OEM rubber.

[Aussie]

Mine was exactly the same.

Just take it to a car window place and they should be able to fix it for free for you, if they are a good bloke.

It took them like 2 minutes, they have a special tool for pulling up the rubber, so as not to damage the paint, and then they just put some more sealer under the rubber.

Mines good as new now.

[Zeke]

This thread is useful. Definitely what he said about the PCNA seal. Good info on the dum-dum (old fashioned term).

The problem with taking it to someone is finding someone with specific 911 glass experience. Since the advent of mobile glass installers, it seems like the real pros have all disappeared.

[RussianBlue]

Wow, some interesting advice - no offense.

Anyhow this job is rather a PITA BUT if you undertake it please do it to the quality that Porsche would do it.

To address your main concern ie: the floppy edges:

The last thing I want to see on any car I might buy is any type of putty/past/silicone underneath a seal.... that said here's the complete job for you:

It is a 2 man job.

Cut the old rubber out so that you can simply lift the window out

Leave the inside half with the wiring on the car until you can lay the NEW rubber on top of it to guide where you will cut tiny holes for the defroster wires

Once the holes are cut then remove the rest of the rubber

Okay - outside the car FIRST lube up the seal w/ STP stuff or armorall or similar - spray the biatch down!

Put the defroster wires into there proper location in the rubber at the car

Here is where the second person is a must
Place the window inside of the rubber in it's proper channel hooking in the wire terminals

The HARD part - tease the chrome into it's proper channel - takes a special 2 thumb technique - HA not funny

Find the proper WAXED string (home depot) and place it in it's proper channel overlapping a good foot or so

Center the window as best as you can then ram it as high as you can

Now one person inside and one out

Inside guy pulls the string and guides person #2
Person #2 follows string carefully - and carefully pushes mainly on the chrome and rubber NOT the window

The corners are TRICKY - make a tool out of wood with a channel the shape of the chrome semi-dome top and use this in the corners to push judiciously while the string is doing it's thing there.

If you can keep the chrome in check things will go better.

Once you got the beast in and if you properly lubed the crap out of it at the begininng - you can grab the window from inside and out and move it around - side to side or up and down - whatever

There is your problem - move your window up using TWO people on both sides - it will seem as if you are doing nothing but it will fix your problem.

You will still need to use a thin metal or plastic semi-rigid tool to uncurl the edges BUT they will stay if the window is centered properly!!!!!!!

Porsche winodw rubber is a complicated part indeed - and it is designed to fit as I have described WITHOUT the use of fillers!

Do it right or don't do it at all - and not every "glass shop" can do it right either.

Do you need pics??

Hope this long a$$ post helps if you decide to undertake this PITA job.

[kycarguy 935]

I also have done the rear many many times myself and I think its the easiest of the windows. The front windshield scares the crap out of me because I broke a brand new windshield once. They are fragile but the rear windows are pretty strong. I need to add I use the factory rubber only.

I poke small holes where the wires go then poke the wires through then add some black weather goop then soap up the rubber with your choice of lubricant, use the pull rope and it usually goes in right the first try. Good luck.

I thought I posted to this thread already but it was another asking about the rear glass R and R.

PS: If you have some help its much easier and I always make sure the rear 1/4 glass is out so I can reach through myself and pull the rope with one hand and press down with the other.

[GeorgeK]

"Porsche winodw rubber is a complicated part indeed - and it is designed to fit as I have described WITHOUT the use of fillers!"

While the rest of the contribution is spot on, I take exception to that. The factory did *frequently* use caulking material on the corners of window openings. I take that from taking more than one original glass out (from cars that are known to have their original glass). The tolerances for these corners were not the best from the factory.
Now if the outer lip "falls in", it is for a reason: too much space there. No puling of the seal at this precise location will solve the problem. The lip will fall back precisely for the reason it fell in the first time: too much space there. You can try to wiggle the window into place (with suction cups to hold the glass), and sometimes it works. But not always. Then lifting the lip and injecting glass putty can sometimes help.

But trust me on this one: the factory did use caulking material in quite some cars. To quote Dave (dtw):

-Last word on factory using adhesives: (?) we just pulled an original windshield from a '78 Turbo with 50,000 miles. There was a great deal of adhesive material in the windshield channel, especially in the corners. We had no reason to believe this was not a factory install.

[kycarguy 935]

-Last word on factory using adhesives: (?) we just pulled an original windshield from a '78 Turbo with 50,000 miles. There was a great deal of adhesive material in the windshield channel, especially in the corners. We had no reason to believe this was not a factory install. [/B]

George,

I found the same on my factory 79 turbo when I took the windshield out about a year ago.