mike cap

One of the idiosyncrasies (some would say crappy design) of the 993 is the space under the trim seal on the front and rear windshields designed to hold water and create a rust problem. This is particularly a problem at the left and right windshield's lower corners where water can sit

There is a Porsche service bulletin that addresses filling the cavity with a Bostic silastic product and there are several great RL posts that detail how to do this. Wurth Bond and Seal was used in one post and it is possible to do a beautiful job following the posts and service bulletin.

The only potential downside I see to the "bond and seal" product is that it is there to stay. If the need arrives to replace a front or rear windshield, I think getting the ws out would be difficult and removing the bond and seal product from the body near impossible.

One option that I investigated was using a semi-permanent filler. I settled on the 3M Window Weld Auto Glass Ribbon Sealer in 1/4" and 5/16" diameter. This product is designed to fill gaps and bond windshields to body work. It has the consistency of warm bubble gum and will stay flexible and removable. Once installed it will be impervious to moisture but if the worst happens getting it back out of the space around the ws is possible - not a fun job given the consistency of this product and its stickiness, but doable.

I used the two different diameters and took my time working the product into the cavities. High tech instruments like stir sticks were used. A soapy "slip" solution is a help to smooth out the install and 3M Adhesive Remover solvent to clean up any residue. The Window Weld is tough to work with and tacky. I did a section at a time over a few days for my sanity. The Porsche factory rubber trim fits over perfectly just like it would with the bond and seal fill.

Photos below.....

Mr Swed

Nice find, I may try this! wonder if it will help against the creeking that can come from the rubber trim?

rlme36

What about a combo of the two? Using "the rope" as filler rod so that that less goop is needed. I guess some concern could be that water retains between the goop and the rope. hmm (que jeopardy theme music).

goofballdeluxe

Sorry Mike, but I think that looks pretty terrible, unless of course, all that goop is going to be hidden underneath the window trim seal?

I went with the Porsche OEM windshield "rope" that not only filled in the cavity, but also had the intended effect of killing any creaking/squeaking sound.

The rope filled the entire cavity, and is completely invisible since it's tucked in underneath.

Here's the link to my fix that I posted a few years ago, if you're interested:

https://rennlist.com/forums/993-foru...ield-rope.html

ble2011

My concern with doing something like this is with the caulk or rope, how do you know you've actually filled the entire cavity without leaving a gap of some kind? If water were to enter the newly created gap, your back to the same problem and maybe worse because the water may not be able to dry out as well as before.

mike cap

The 3M filler is completely covered by the window trim seal so it will never be seen.

If done with a little care there is no way that water will penetrate the cavity and collect. If you buy a roll of the product and play with doing the fill you'll see what I mean. It is made to fill gaps, adhere to virtually anything and mold itself to any surface variations.

mike cap

Also the 3M product fill should do a great job of eliminating the window creak.

Top-Gun

Seems to serve the same purpose as the Bostic sealant in the Porsche TSB, but a little friendlier to remove later.

Another option I've adopted is to spray a non-drying anti corrosion wax in the channel around the window. Something like Dinitrol or Fluidfilm that dries to a wax rather than remaining viscous. Water still gets in but the wax seals everything up and prevents corrosion from starting. Still a good idea to periodically blow some compressed air in there to clear it out.

mike cap

That is a good idea. I actually bought a product called Waxoyl and was going to do the same thing and then stumbled on the 3M product. I am going to use the Bostic (Wurth actually) on the rear ws since the likelihood of having to replace it and remove the permanent sealant is much less

nine9six

Bruce7 did a very nice DIY using the Wurth product, on both the front and rear windows.

Mike J

Is that stuff actually that sticky that it bonds to each painted surface as not to let any water pass? If any water gets past it, its actually worse than it being open, evaporation and venting will be much harder ...

CaptainGSR

Does the window trim seal just pull out? Or, is it sandwiched between the window and the body, like the rear side windows for example?
I want to replace mine because the fitment is marginal and I have a 1 mm gap on the lower driver's side corner that lets water accumulate in the cavity...

Mike J

It is removable but you need to be careful - for instance you do not want pull a lot on it and stretch it too much, the seal will be too long then (which you find out about 5" from the end. You can reinstall it, but it takes strong fingers - I usually use soap water as a lube when I do one. As far as position goes, there is a joint in the seal, I put that at the lower center of the window to center the entire seal.

Cheers,

Mike

Aaron 993C2

I am getting some rust fixed this winter in my rear window seal, I've heard mixed results with the rope that Porsche recommends, this might be the better option that I'm looking for to prevent the rust from returning. Thanks!

Mr Swed

correct me if I´m wrong, but the roping is a 996 TSB that some use on the 993. The TSB for the 993 was to fill the gap with a Bostic silastic product. I´v tryed that years ago but there´s still issue with moisture traping under the sealent.

if you want to rust protect I would not seal the gap, but use a wax based rust protector.
If you got creeking, well thats an other issue !!