1985 1/2 rear hatch leak

[Dean Gurko]

I've noticed that the metal strip around the outside of my rear hatch is seperating from the glass. This must be where the air and water leak is coming from (one of my back seats is soaked).

Is there an easy way to fix this without removing the hatch itself? Can some please provide tips and/or web site info on this?

If it's repairable, I'm confident that I can do it (ie: I swapped out engines earlier this year and am mechanically inclined).

Thanks very much,
Dean
Dean_Gurko@yahoo.com

[lordgrommit]

I've had some luck the hatch comes off with just a couple of bolts. I then used glass pvc and stuck it in seems to work pretty well and it cost $4

Matt

[Dean Gurko]

Thanks for the tips guys. I used some DAP Qwik Seal (clear) caulking last night to fill in the gaps. This is just a band-aid until I decide whether or not to swap the hatch between my two cars, or take off the gapped one, and repair it like lordgrommit did...

Dean

[Gordon Rankin]

Dean,
There was a tech article in this tech forum a few months back that discusses this. It has to do with removing the glass from the car and separating the metel moulding from the glass and gluing it back together with a form of super adhesive. Anyway I will try to find it again and send it to you.
Gordon

[species]

I just took mine to a glass shop and they removed it from the frame and resealed it for $40.

[1.2gees]

Let us know if it lasts!
Ahmet

------------------
It's all the driver...

[Gordon Rankin]

From www.Porsche.Org. Tech Tips:


1 - Rear Hatch Reseal
The rear hatch seal of the thin aluminum frame to the heavy glass, a design used on all of the 924/944/968 series, has one major flaw. Very strong struts are used to lift the heavy (est. 80 lbs) piece of glass with it's corresponding frame. These exert a lot of force when fully compressed, with the hatch closed. Due to the design of the hatch, with the aluminum frame representing only a small portion of the hatch structure and weight, the entire extent of that force is transferred to the bond between the glass and the aluminum frame. Over time, this bond will deteriorate and separate, resulting in a leaking, rattling hatch. The only option is to reseal the hatch with 3M's windsheild adhesive, either by following the procedure outlined below or by taking the vehicle to a glass shop that will perform the work. The hatch can be removed as per the instructions in the Haynes manual; open the hatch, disconnect the struts, and remove the four socket head screws at the hinges, under plastic caps in the rear of the roof lining. What follows is an article from Jim Demas describing the process:



Hatch Reseal Procedure
I have seen posts regarding help on subjects such as rebonding the rear hatch frame to the glass. I will outline here what I have used in many concours restorations.

The procedure is almost the same as for setting bonded windshields... and uses the same material... a super strong isocyanate urethane bonding caulk from 3M. 3M claims that it "Exceeds OEM strength requirements." They are truly not kidding. I have used this stuff for precisely these two uses... and a word of caution is on order at this point... it is the strongest pliable sealant around. Unbelievable stuff... as you cannot tear a dried 3 inch long piece from the cartridge nozzle later.

Make sure that you put it where you want it before it dries... it is tremendously tough stuff... and very hard to remove from improper areas once cured!

What is it? 3M "Window-Weld Primerless Super Fast Urethane Auto Glass Sealant." It is part #08609... and comes in a cartridge gun tube of 10 fl. oz. (295.7ml). It is made by their Automotive Trades Division... and is sold by companies who supply body shops and auto glass shops (almost all auto paint wholesalers carry it). One tube is sufficient for one hatch, with a little left over.


Directions...


1. The bonding surface on the frame (or in the case of windshield, the pinchweld) should be clean and dry (remove dirt and as much of the old sealant as possible). A heat gun may ease removal of the old sealant.

2. Prime any bare metal with 3M Super Fast Urethane Primer, Part #08608

3. Clean glass with 3M Glass Cleaner, part #08968. Windshields (or rear windows) that do not have a black ceramic band on the perimeter (to hide the sealant) will require priming with 3M Super Fast Urethane Primer, part #08608, for UV protection of the bond (this is one reason why the bond fails in many of the hatch frame separations).

4. With sealant cartridge in a cartridge gun, and the nozzle cut to the desired bead size you wish (1/4" is preferable)... apply the sealant to the frame (if a windshield)... or to the glass(if a hatch... you can apply it to the frame if you wish... whatever is easier for you).

5. Position the glass or the frame onto the surface which has had the sealant put on it... place in final location... and gently press for proper fitting. You may paddle the sealant around the edges if desired.

6. Clean up using 3M General Purpose Adhesive Cleaner (great for removing old decal and pinstriping glue residue, too)... part #08984 or 08986.

7. Let cure. Higher temperature and humidity makes the sealant cure faster... lower cures slower. Though it firms up in a few hours and sooner than this... 24 hours is a good timeframe for proper curing. If you can... give a hatch 48 hours before using to give it the extra strength of a very full cure. The hatch is a very stressed unit... much more than a windshield (remember: a windshield sits on the glue... the hatch does just the opposite). Avoid reconnecting the hatch struts for as long as you can bear.

8. You are now done! And you have fixed the windshield or hatch as good as new or better. This stuff is amazingly strong and tough. - Jim Demas

And Russ Bullock also shared his experience with a slight twist:

Well folks, I finally got the glass separated from the frame. The two feet
of
snow that we got last week had just about everything shut down, and I
finally
had time to work in this project. I've not yet obtained the proper
re-sealing
material (3M "Window-Weld Primerless Super Fast Urethane Auto Glass
Sealant - part #08609)due to the abovementioned snow storm, but here are
a few tips that I developed by trial and error that might help with the
separation.

1) If you have the rear hatch wiper, getting the hatch off involves an
additional
step that even the factory manual doesn't mention. The power and control
wires for the wiper must be disconnected from the wiring harness. This
connection is not anywhere near where the wires feed into the rear body
pillar. It is accessable thru the side panel. Then these wires must be
withdrawn thru the hole in the rear pillar near the top of the hatch. I
nearly
yanked them out in a bad sort of way when I first tried to remove the hatch.

2) Removing the spoiler trim is a royal PITA! The top trim was a snap.
The side trim is attached with what I would call knurled-knob nuts which
have nearly useless flat-blade slots in the top of them. The factory must
use a special tool to fit over the stud and engage these slots on each
side of the nut. I used brute force (i.e., a pair of vise-grips). The rear
spoiler is attached with phillips head machine screws with a hardness
rating similar to that of warm butter. I actually got a couple of them off
with a screw driver, but most had to be drilled out.

3) The sealing compound had completely let go from the glass at the
left hinge, which was the motivating factor behind this project, but the
remainder of the seal was still very much intact. Separating the glass
from the frame is the toughest part of the job. I started with a 1.5"
wide flexible putty knife to slip between the glass and the seal. The
metal blade and the amazing rubber-kryptonite sealant did not want
to slip past each other without considerable force and a variety of
four-letter words. WD-40 applied to the working surfaces helped greatly.
I also sharpened the end of the blade by grinding on only one side
(like scissors) and used the unground side on the glass side of the bond.
In addition to this putty knife operation, draw your attention to the top
side
of the hatch and use a good sharp utility knife to cut the outer edge of the
glass from the sealant. WD-40 comes in handy here too. Cutting this
edge bond first allows the putty knife operation on the other side of the
glass to go a little more smoothly. I kept a thin block of wood wedged
between the glass and frame where I had already achieved separation.
This helped to force open the gap so that the putty knife could do its job.
Take care with the wedge block so that the frame is flexed, but not bent.
Overall, it took me four hours to separate the glass from the frame.

4) Once separated, I cleaned the glass of remaining sealant with a razor
blade scraper followed by 4X steel wool. I tried using a Scrub-Brite pad,
but found that it left slight scratches in the glass surface. I used
some fine polishing compound and a cotton cloth to remove scratches
that might be seen after the glass is re-bonded. I might actually grind or
sand a rough surface into the glass at the bonding surfaces near the hinges
to make a stronger bond there. Any thoughts or warnings about this idea
would be most appreciated.

5) Concerning the use of solvents to soften the sealant: GOOD LUCK!
I even went so far as to try GumOut carb cleaner, the stuff with Xylene
and other possibly carcinogenic (and definitely flamable) solvents.
That sealant took everything I could throw at it, then threatened to taunt
me a second time. Apparently the only thing that can make this stuff
turn loose is 20 years of UV solar radiation.

Well, that's about as far as I got with the job before my electricity went
off
due to the ice storm which followed the snow storm. We enjoy a little snow
now and then here in North Carolina, but this is getting ridiculous!

Good luck to all those with a similar condition to their 924/931/944/951/968
rear hatch. Porsche AG obviously did not intend these hatches to be a
repairable item. I guess they just expect us to buy another one, another
Porsche that is.



[This message has been edited by Gordon Rankin (edited 04-01-2001).]

[Dean Gurko]

All that replied, a big thanks to you!
Cost wise it looks like getting the metal sealed back onto the glass isn't an issue. Getting the glass off the and into the shop will be the most difficult part, and I don't mean really the labor itself, just being careful with that heavy glass!

Dean