Winter is here, and I have leaks.

[jt20]

Instead of replacing seals on rear wagon windows and winshield.. has anyone had success caulking? What brand did you use and how did you apply it?
I am very adept w/ caulking and the proper application.

[Pete Geither]

My personal opinion is forget about the caulking. I have never seen a good seal or repair made without pulling the window out and putting the factory seal or proper sealants in place. Ask any good glass shop.

[Chad300tdt]

Before I replaced my quarter window seals and repaired the rust, I stopped all the leaks with Butyl Rubber Sealant and Flowable Silicone.

I used the butyl between the seal and the car. I used the silicone between the window and the seal. DON'T USE SILICONE AGAINST ANY METAL. It traps corrosive moisture as it cures and causes rust.

Use Painter's tape around the seal to protect your paint and squeeze a bead of butyl under the seal just until it fills the void. Then wipe up the excess with mineral spirits and peel off the tape. Run a bead of the silicone between the glass and seal and once it cures go back with a razor blade and trim off any globs that form. It will be nearly impossible to get any sealant around the seal at the top of the quarter windows, but they don't usually leak from up there anyway. Just get the bottom edge and the rear most corner thoroughly and go up as far on the sides as you can. The rear window is easy.

You have to use sealant even on new seals or they will leak. The correct sealant to use according to MB is "MB Window Sealing Compound" part # 001 989 31 20. It stays flexible like the butyl rubber sealant and doesn't promote rot like silicone.

Good luck.


EDIT: Here's the thread I did when I worked on my quarter windows:
http://www.peachparts.com/shopforum/diesel-discussion/201820-300td-quarter-window-removal-w-pics-post1937709.html?posted=1#post1937709

You'll need to pull the horizontal trim at the base of the window to gain access to the bottom edge of the seal. I would try the sealant between the glass and seal first. If that doesn't seal your leaks, then move forward with sealing between the seal and car. You will almost definitely rip one or two clips out of the car due to rotted rivets. I actually ended up just drilling all of them out and using new rivets before I reinstalled that trim piece.

ALSO: I used butyl between the glass and seal with my new seal because silicone glues the seal to the glass and makes it difficult to remove later if needed. The butyl is easier to deal with in the future as is the MB Window Sealing Compound.