84 300td windshield reseal - PeachParts Mercedes-Benz Forum

chrisgt · #1 09-13-2016, 08:07 AM

Pretty sure my windshield gasket is leaking, since I park on a hill water is running under the front floor mats and turning the back seat foot wells into a swimming pool. Not good.

Can I just have autolite or some glass company pull the windshield and reseal it, or are they likely to screw it up?

Also, should I spring for the (kind of expensive) mercedes windshield gasket, or will whatever aftermarket one they supply be fine?

vonsmog · #2 09-13-2016, 08:22 AM

I put one of the aftermarket gaskets in my 85' TD with a new windshield after restoring the car. We used the sticky stuff that is like a rope for the contact between seal and car. And used the sealer with a caulk gun between seal and glass. It has been only a few months, but all is fine so far. Car has been outside for a few weeks, while the garage is full of stuff for a few weeks.

koooop · #3 09-13-2016, 09:14 AM

There was crap in the drain under the hood next to the spring in mine. The blocked drain hole was my culprit.

funola · #4 09-13-2016, 09:32 AM

I'd verify the windshield is leaking (and not elsewhere) before replacing it. I'd suggest removing the dash for easier inspection, stuffing the bottom edge with bath towel and wait for it to rain and see where and if the towel gets wet.

ah-kay · #5 09-13-2016, 01:08 PM

I just fixed mine. It was leaking at the lower right hand corner of the windshield glass. I removed the under dash panel and used a 2 gallons pressured water bottle to spray water onto the windshield, mainly near the corner area. I saw damp patch on the felt under the dash, right underneath the glass corner.

I cleaned the corner well and sealed it with silicon sealant. Redid the test and no more damp patch. Put the under dash panel back and keep my finger crossed. Your leak may differ but it is worth a try,

Demothen · #6 09-13-2016, 01:20 PM

If you used silicone in contact with the metal, I would strongly consider removing that and replacing it with something else. Silicone releases something corrosive as it cures, i forget exactly what though.

ah-kay · #7 09-13-2016, 01:36 PM

Quote:

Originally Posted by Demothen

If you used silicone in contact with the metal, I would strongly consider removing that and replacing it with something else. Silicone releases something corrosive as it cures, i forget exactly what though.

You want water ingress and corrode all metal or a little of silicon sealant which fix the problem. If you don't remember or have the facts, please refrain from posting useless info.

Diesel911 · #8 09-13-2016, 01:39 PM

If there is rusted through area under the Windshield Gasket who is going to fix that?

ah-kay · #9 09-13-2016, 01:46 PM

Quote:

Originally Posted by Diesel911

If there is rusted through area under the Windshield Gasket who is going to fix that?

NO ONE. I am not a perfectionist. Why would someone remove the windshield to get rid of some rust underneath it? There are a lot of places in a 30+ years old car with rust - all in hidden positions. Am I going to fix them? No.

Demothen · #10 09-13-2016, 01:56 PM

Have you ever seen what happens when silicone is used to seal a windshield? Because I certainly have, that as well as silicone sealant at the bottom of door frames on an old VW I owned had caused enough rust to seriously impact the ability to restore the car, and lead to me selling it to someone who wanted to build a dune buggy. There are alternative sealants that arent corrosive.

Whether you like my advice or not, I am well within my rights to offer it. You may not agree, thats great, but someone else might find the information useful.

As far as "all the facts" - I'm sorry, I'm not a chemist, but here's a little research.
http://forum.w116.org/auto-torque/silicone-sealants-and-rust/
http://www.jeepsunlimited.com/forums/showthread.php?141742-RTV-sealant-can-cause-rust
https://en.wikipedia.org/wiki/RTV_silicone "Certain types of RTV release acetic acid during the curing process, and this can attack solder joints, causing the solder to detach from the copper wire."

And I would remove a windshield to fix rust under it. I'm dreading that job on my W123 and hoping I don't have any major rust.

rocky raccoon · #11 09-13-2016, 02:04 PM

is a common problem on old cars. Any competent body shop can repair/rebuild that channel. I had it done on the rear windshield of my coupe. In that case I paid a glass shop to r&r the windshields since coupe rear windows are as rare as a hens teeth and I wanted to take no chances.

After the channel is repaired, use a new gasket rather than trying to replace the old one.

Demothen · #12 09-13-2016, 02:06 PM

Quote:

Originally Posted by rocky raccoon

is a common problem on old cars. Any competent body shop can repair/rebuild that channel. I had it done on the rear windshield of my coupe. In that case I paid a glass shop to r&r the windshields since coupe rear windows are as rare as a Hens teeth and I wanted to take no chances.

After the channel is repaired, use a new gasket rather than trying to replace the old one.

How do they typically repair it? I'd think welding would probably ruin the paint. I was thinking por15 and epoxy putty possibly, if I find any rust through - otherwise just cleaning it up and using por15. Or is this something that's typically done on cars in need of paint jobs?

ah-kay · #13 09-13-2016, 02:20 PM

Quote:

Originally Posted by Demothen

Have you ever seen what happens when silicone is used to seal a windshield? Because I certainly have, that as well as silicone sealant at the bottom of door frames on an old VW I owned had caused enough rust to seriously impact the ability to restore the car, and lead to me selling it to someone who wanted to build a dune buggy. There are alternative sealants that arent corrosive.

Whether you like my advice or not, I am well within my rights to offer it. You may not agree, thats great, but someone else might find the information useful.

As far as "all the facts" - I'm sorry, I'm not a chemist, but here's a little research.
Silicone sealants and rust
RTV sealant can cause rust?
https://en.wikipedia.org/wiki/RTV_silicone "Certain types of RTV release acetic acid during the curing process, and this can attack solder joints, causing the solder to detach from the copper wire."

And I would remove a windshield to fix rust under it. I'm dreading that job on my W123 and hoping I don't have any major rust.

I am offering my 'been there done it' experience, diagnostic, fix and retest procedures to the OP. You offer nothing of value to the OP except to remove the windshield, fix all rust underneath, reinstall with new everything with professional help at $$$. The car may or may not be museum quality, mine is not, so silicon is the way to go. If it fixes it then all is well, if not then I will think of something else.

btw: I do not think silicon sealant will ruin any metal or paint or cannot be reversed. Good luck guys.

Demothen · #14 09-13-2016, 02:26 PM

Actually I never suggested anything other than don't use silicone, using something else would probably be fine.

rocky raccoon · #15 09-13-2016, 02:27 PM

Demothen: Yes, a new channel must be built up and welded in. Part of the job is to paint the repair.

Those that counsel gobbing on sealants and the like are satisfied with a temporary repair. It will not last very long. If you like your car and daily-drive it as I do I recommend doing it the right way. Not very expensive as body work goes. Cost me about $350 including the $90 to the glass shop for r&r. Oh, of course plus the new gasket which was horribly expensive for my coupe, much, much less expensive for a sedan.

Been about 3 years now. No leaks.