Windshield seal leak => Rear floor puddle?
 

Hi all,
I've noticed a little puddle in the back of my 84 and I keep looking around from time to time for things it could be. I noticed my rear window (rear windshield?!) has a new seal, also my front windshield has a new window but an old seal?! :confused: So I just rinsed the ole' benz off at a quarter wash and noticed three beads of water rolled down on the inside?!? Could this contribute to my rear passenger side water puddle or is this another battle? So far I've cleaned all my vents and fixed the rust spot by the battery but it's still wet at times back there. Also how hard is it to change the seal myself (maybe with another helper...)? I like to do ALL the work myself instead of the stealership or some mechanic....

Thanks,
Jeff M.

I had a new windshield and seal installed in my 240D about a year ago, and shortly thereafter noted the "old water in the rear floor" syndrome (drivers side). I cleared all of the drains and figured that this had cured my problem, however, it did not help. I noticed during a pretty heavy downpour that I was getting a leak at the driver side corner of the windshield. So I bought some silicone sealer at Advance Auto and carefully sealed about 25% of the windshield at the suspect area.

Problem resolved...no more leaks or water in the floor. Just completed one of the wettest months on record in Alabama (I garage car at night, but park it at work during the day). So....yes windshield leaks can easily be the reason for the "old water in the rear floor" syndrome....and several other reasons that you can find using the search key in this forum.

Good luck.

Yepper, probably the windshield. My '84 300D leaked when I got it. Water ran down the sheet metal at the passenger side kick panel, under the carpet, then back to collect at the low point...passenger side, rear footwell. New windshield seal (when I got new glass) fixed it.

fmb

You should most definitely clear the four drains and remove the battery tray to check for rust before disturbing the windshield.

There is a drain below each hood hinge, another under/behind the master cylinder and another under/behind the battery. I have been there, done that and this is the most common source of leaks of water into the rear floorboards.

Good luck,

As have I, that is why I'm blaiming the windshield. :) All my vents can take down a gallon of water in a minute or less. I also had a little hole which turned into a inch round hole under the battery, it is repaired now. While all my side window seals are all cracked up I don't think they are leaking at all in normal rain. So I guess I'll replace the windshield seal next. Thanks for all the replies so far, has anyone changed the seal themselves? Or is this not worth the effort and I should just take it to a glass shop?

Thanks again,
Jeff M.

I would rate a windshield seal replacement as a very difficult DIY job. My experience shows that even a professional can install a new seal such that it will leak. I have installed windshields in other vehicles and it is a real pain. For the fee a glass shop would charge (probably <$100) it's not worth the hassel.

If the seal is not in bad shape...I would take a stab at sealing it with silicone sealant....its cheap and effective.

It isn't very pliable and looks like crap. Well the thing which concerns me is the car was repainted by some animal, it looks like it used to have some sealant there that he painted over. I have a feeling if I hire it out they'll hack it and I'll still have a leak. Maybe I'll have to cobble or, gulp, repaint the roof in order to get it to seal correctly. Maybe I should go snap a pic.

~jm

Most self explaining picture.

notice the crap gummed up that was painted over

I did my rear glass, successfully I might add. I wasn't easy and required 3 people. The windshield looks more difficult. I would worry in your case that there is rust or areas that aren't smooth under the seal that need attention to allow the new seal to work properly. Paying for a seal replacement may not result in damage being repaired correctly. I would remove the glass myself and fix any damage, paint whatever is necessary, etc. Order the seal yourself. If you don't think you can handle the reinstallation then pay someone else. Get the correct sealant from MB. Don't let the glass monkeys tell you otherwise. RT

I doubt there would be rust underneath as it was a southern car, then again nothing suprises me anymore. I almost think I will try it, do you use the sealant on both sides? I can't imagine the seal just setting on the car inorder to make its waterproof seal.

~jm

btw- tonight driving in the rain more water started down the inside of the windshield so I suppose I better fix this pretty quick.

From the pictures it looks like a bad molding. Check the window rubber- Does it lift in the corners? Does it snap back quickly when you lift it?

I posted the following last November, regarding windshield molding, but also about replacing the gasket:

You can remove them but there is a good chance they will get bent. You have to use a tool that helps you gently lift them out. They are soft aluminum. Only a slight angle at a time. They have a slight bulb at the bottom of where they are inserted into the rubber gasket. You have to lift this bulb section out of the rubber holding it. You do just a little at a time. NOT all the way out all at once.

If your windshield gasket is old and hard, just cut it out as suggested and replace it.

A good quick test of the gasket is to lift a flap. If it snaps back it is probably good. If it falls back slowly (anything other than snapping back) it is aged and will eventually start leaking.

And installing the window: Definitely put the gasket around the window, install the metal frame, lube with something like spray silicone both to insert the molding into the gasket and to help the gasket's rubber flap slide over the corresponding metal channel of the body of the car. Use a nylon rope, greater than 1/4", better 3/8" which is inserted all around the the deep channel in the rubber gasket and have it overlap at the bottom.

Insert this assembly into the car (from the outside) with the top into the metal channel first. Make sure the sides are aligned, push the top against and into the channel at the top first

Have a friend help by applying even and light to moderate pressure just to hold the glass against the metal body channel at the bottom. Nothing intense, just holding it down. Start pulling the rope and have the assistant *gently* slap the glass as you pull, going all the way around the glass. In this process you can adjust a little bit. If you are way off, start over.

To help the rubber flap of the gasket get over the metal channel of the body, you can use a *very* soft headed, rounded end, metal or plastic tool. You can buy cheap auto glass tools just about anywhere.

I have done four windshields/back glass this way and each have worked out great. An old glassman showed me all this years ago.

Hopefully this was clear.

Haasman

Benz boot,

I did my W123 rear glass last month. IT was easy!! Ok- my wrists were a little sore from working with the rubber seal.

I'd be happy to give input if you have problems. My wife was only there to help push on the glass during installation and moving the glass on removal/getting it ready for the new seal.


Michael

The rubber is indeed bad, you can almost drive a truck through the gap it left ;), and isn't one sharp edge anymore but pieces. Great thanks for the instructions Haasman, so I put sealant just where the glass sets or there and where it meets the car? So it mainly seals on a fairly sharp edge of the roof then?

That is great to hear that it was easy, did you use the rope method that Haasman details? Thanks for the offer Samiam4, hopefully things go smoothly. Next time I order some parts I guess I'll get that as well. It already ruined the foamish piece with the sun visors, I just figured that was from a previous leak.

Thanks for all the replies so far, maybe in a month or so I'll dig this thread up and tell how it went or any complications.

I used the rope method- just be gentle and take your time. I measured the center point of the body and marked it with a grease pencil and did the same for the glass.

Start at the bottom having a helper push. Sealant is generally a bad thing. A new seal will seal. Sealant can trap water and creat rust. I would not use RTV, because when it cures it creates acid, and hence rust.

My wife just put her weight against the glass, I pulled a little, then checked for progress on centering, height etc.. Push and pulled a little, then continued. Once the bottom is done, it's not going to move much.
In mine, it did dribble water for about the first week- then we had some warm days, and the seal settled into place.

It's rewarding when it's done. Can't believe I ever paid someone $50-100 when it is easy. I was always parinoid about breaking the glass.
Front is more difficult, because you fight the dash and trim stuff more. Back window is cake!!

Michael