POR-15 to prevent delamination on W126 rear window prior to install. Will it work??? - PeachParts Mercedes-Benz Forum

pwogaman · #1 11-05-2006, 02:24 PM

I just pulled a rear window out of a 1988 560SEL that I intend to install in my 1985 300SD as soon as I get a new rubber seal. My current rear window is badly delaminated and I want to prevent this from happening on the replacement. Getting a new rubber seal and using the proper MB sealant I believe is a good start, but as evidenced by the failure of so many windows through delamination out there it is obviously not enough.

My thought as an extra measure of protection is to use a "Q-tip" to apply a thin amount of POR-15 around the outer edge of the window (not on the flat inside or outside) thus covering the seam at the laminated glass sheets prior to installing the rubber seal.

Anybody ever tried it? Any reason not to do it? Any down sides anyone can think of? Would I be wasting my time?

Rick76 · #2 11-05-2006, 04:20 PM

I've never tried POR-15 on glass - not sure how it would stick over time. Sure sticks to rust and skin!
I treat the edge as one would if installing a front window with urethane. Apply the clear prep then paint the edge with the black urethane primer. I then apply a very thin coat of urethane to the edge with a finger (wearing gloves of course). Watch out for slivers of glass. After the urethane has cured, take a razor blade and cut off any excess.

Hatterasguy · #3 11-05-2006, 06:29 PM

The plastic that holds the glass together fails with age. Not much you can do about it.

raymr · #4 11-05-2006, 07:04 PM

Mine has the delamination problem also. I found that after i recaulked the rubber seal around the glass, the fogginess slowly went away, but half the defroster element is still gone.

pwogaman · #5 11-05-2006, 11:17 PM

Quote:

Originally Posted by raymr

Mine has the delamination problem also. I found that after i recaulked the rubber seal around the glass, the fogginess slowly went away, but half the defroster element is still gone.

Are you serious? The cloudiness actually went away?

I can understand the defroster not coming back to life, but I also thought for sure the cloudiness would linger on as well. If that is the case then I might just hang onto the window I am going to remove as a spare.

Rick76 · #6 11-06-2006, 04:12 AM

I once sent a rear window from an SLC to a glass manufacturing company where they heated the glass in clay. The fogging around the edges disappeared completely. Unfortunately they heated it too much and some of the heater wires melted.

The fogging of the plastic layer is caused by moisture exposure, so sealing the edge will prevent it.

DrLou · #7 11-13-2006, 02:30 PM

Guys,

I am about to replace my rear window and, as it looks like you are all in the same boat, thought this might be a place to start. I have the well-known fogging problem, as well as a wet trunk issue.

A couple of ?s, if I may:

Has anyone yet replaced his rear window himself? Are there any big gotchas or other stuff to look out for? Any reinstall tips? Had no trouble getting the replacement out of a cemetery car; suspect reinstalling it will be a bit trickier... I do have the new MB rubber seals for the job, both for window and trunk.

Is the trunk water likely coming from my poor rear window seal? Or is it more likely from (my springtime project) a leaky sunroof?

Any insights are greatly appreciated, preferably before I wind up with a gaping hole in the back of the car as winter rolls around!

Lou

raymr · #8 11-13-2006, 02:58 PM

You have to be careful with the aluminum trim, as it may kink and you can't unkink it. Lots of search references are available regarding rear window replacement.

Also check the seal around the antenna base for seepage. Its easily replaced.

pwogaman · #9 11-13-2006, 03:10 PM

Yet another source for water in the trunk is through the top of the tail light. Water drains down from the top of the car and gets in the trunk fender seam. From there if flows back to the rear of the car directly on top of the tail lights. It should then flow towards the middle of the car by the license plate and onto the ground. If you've got gunk on top of your taillight and the seal is old then it can get in your trunk that way.

TX76513 · #10 11-13-2006, 03:16 PM

You shouldn't have a delamination problem with the newer style glass. Manufacturing has come a few steps in twenty one years.