W126 water in trunk - PeachParts Mercedes-Benz Forum

bschwar · #1 11-08-2005, 04:45 PM

Hi all, I'm trying to figure out where the water is coming from in the left (drivers) side trunk well of my 84 300SD. I've got a minor case of the rear glass delaminating, so that is a suspect. Before I spring for new glass, I'd like to cover my bases. There is some form of a drain in the well, but the top of it is not connected to anything. Where is this supposed to go? Is it a water drain? I was wondering if it could be the sunroof drain. If so, that could explain things.
Barry

donbryce · #2 11-08-2005, 05:47 PM

'85 380SE, same problem. I get water in both wells, left and right of spare tire well. I've ruled out the trunk weatherstrip, as I can't see any penetration anywhere.
I ran a good bead of silicone under the sides and bottom rubber flanges of the rear window seal too, thinking it was seeping in somewhere around the sides/bottom of the glass (BTW, glass was replaced last year, bad delamination both corners, but they re-used the old rubber seal. The new glass wasn't OEM and a bit thinner I thought, so may not have sealed properly) Didn't help.
There's a water drain hole in the bottom of both wells in my model. The left one accomodates the drain tube from the power antenna, which the lack of, or positioning of, may be your problem, especially if you have a non-original power antenna that either lacks this tube or fits poorly at the fender grommet.
I believe my sunroof drains exit at the rear of the rear wheel wells, outside the trunk, so are not suspect. All I can think of now is to get inside the trunk and have my son spray the area liberally with the garden hose. Maybe I can see where it's coming from if the carpet liners are out....but that may not happen until spring. Hope my comments help.

andmoon · #3 11-08-2005, 07:01 PM

Mine were leaking from the rear lights. A hose to the lights while looking in might show the leak. There are 2 hgaskets per side involved. 1 is between the light assembly and body. 2 is the red white and yellow portion of the light and the black body of the assembly.

raymr · #4 11-08-2005, 10:35 PM

Mine was leaking heavily from the forward area below the rear window. I sealed the ENTIRE back window glass-to-rubber union with black marine sealant. Also sealed the top and sides where the rubber contacts the body with the same material. No leaks since. Prep is very important, as a lot of gunk settles in there which will make the sealant not work. Several hours of cleaning with rags, alcohol, and popsicle sticks is required.

Hatterasguy · #5 11-08-2005, 10:36 PM

If you are getting water on the drivers side replace this seal:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1MB12FET61NN1CBMXU&year=1987&make=MB&model=300-SDL-001&category=Z&part=Antenna+Seal

It costs nothing takes a few minutes and is usually the suspect.

Water can also come in from behind your tail lights.

Now water should not come in from the rear glass regardless of the glass or its seals condition. Their is a metal lip under the glass that will not let water into the trunk, unless it is rusted through. So if you are getting water in your trunk from the rear glass you have a hidden rust problem. I sudjest pulling the glass and dealing with it if you plan on keeping the car.

PaulH · #6 11-08-2005, 10:49 PM

A friend of mine replaced the rear window seal on his '85 300 SD and that stopped the leak in his trunk.

Hatterasguy · #7 11-08-2005, 10:53 PM

It shouldn't have their is just plain sheet metal under the seal. However in each corner their is a hole that the factory made for some reason when they were building the cars. They are usually filled with paint and body filler, it is possible that one could have come un plugged.

raymr · #8 11-08-2005, 10:58 PM

Quote:

Originally Posted by Hatterasguy

Now water should not come in from the rear glass regardless of the glass or its seals condition. Their is a metal lip under the glass that will not let water into the trunk, unless it is rusted through. So if you are getting water in your trunk from the rear glass you have a hidden rust problem. I sudjest pulling the glass and dealing with it if you plan on keeping the car.

This is my problem, as water was coming down thru what looks like 2 spotwelded pieces. The prices I got to replace the glass and seal were very high (over $1000), not counting fixing the damage underneath. Sad to say I can't justify the expense. I'm hoping that by stopping the leak, the rust won't progress, or else progress very slowly.

bschwar · #9 11-09-2005, 08:34 AM

I do have an aftermarket antenna, so that explains where that drain was supposed to go. I did get the original antenna handed to me when I bought the car, but I didn't see where the drain would connect to it. I may try putting that back with a new mast and new seal.

I hadn't looked at the tail lights because the water seems to be comming from the front. I may take a closer look, though, because as the saying goes, things are not always as they seem.

I did also have water in the right (passenger) side wheel well. I think I pinned that down to a cracked bellows seal around the fuel fill, and a leaking fuel fill overflow drain tube. Time will tell if I really fixed the water on that side.

As for the rear window, I guess it would be worth it to try sealing it first. How do I go about removing the trim without damaging it, and how tough is it to do?

Thanks again for all the advice
Barry

raymr · #10 11-09-2005, 08:51 AM

If your car is like mine, the aluminum trim cannot be removed unless the whole window is pulled. Instead, I used a popsicle stick (or use anything that general shape) with cloth over it. Force it under the rubber to clean out the crap that collected there. I used alcohol as a solvent. Keep going until the cloth comes out clean. Then seal it by raising the rubber slightly and force a bead of sealant in between as you move along. Better too much than too little, as the extra can be trimmed away. Mask the painted areas though.

Before you do any of that, make you really have a problem there. Rust and/or moisture under the window in the trunk are a dead giveaway. And once again, the correct way to fix this is to reinstall the window with a new seal and repair the rust areas. The above is a low-cost shortcut.

bschwar · #11 11-09-2005, 09:28 AM

Ah, so the rear window is in a rubber seal and not glued in, eh? Interesting. Sounds like old school. So how tough is it to remove the window and replace the seal? How would I go about doing this?
Barry

bschwar · #12 11-09-2005, 11:42 PM

Rain today so I took another look. I found the antenna is loose and I was able to feel some moisture around it. I still don't see any trace where water is flowing, though. I guess I'm 90% convinced it's the antenna that's the problem. I took a good look at the old antenna. It needs more than a mast. Anyone know any good antenna repair/parts threads?

I also found the right side is still getting some water. I now can see water coming from the tail light (the smoking gun) on that side.

Thanks to all.
Barry

Hatterasguy · #13 11-10-2005, 12:32 PM

Pulling the rear window isn't to hard I did mine in a couple of hours. Total cost was $130 for the gasket and MB sealent.

I posted how to a while back so a search should turn it up. But basicaly don't even look at the trim until the window is out of the car. The trim just fits into the gasket as you are fitting it around the rear window.

Anyone who is charging $1k to remove and replace a rear window is way overpriced or doesn't want to work on your car.

hdexpert · #14 11-10-2005, 01:31 PM

I had a few leaks in my 81 300SD and found the easiest way to locate them was to get in the trunk with a flashlight while the wife sprayed various parts of the trunk area. Mine was leaking from the taillight seals,so,being a daily driver,I removed both sides,cleaned them with alcohol and sealed the ****e out of them with black silicone.Worked great,I now have a dry trunk!

86560SEL · #15 01-22-2006, 04:12 PM

OK. Here we go again. This seems like a very common problem on the early W126 cars. As mentioned, I have moisture in my trunk, (1985 380SE - which seems to be a popular car here) as well as my right rear floor panel. I KNOW that my antenna seal is bad - I have a new one, ready to install. I am going to do a search to figure out how to change it. I know water is getting in there, because it rained heavily today and when I looked, I saw beads of water down the antenna motor.

I also know that my right taillight seal is bad, because there is some water in that lens. Today, I noticed heavy condensation on the inside of the trunk lid. Also, as mentioned before, I have some rust spots on the inside of the trunk- under the window. I felt around there and felt some water.

My car is a southern car, with no rust issues, but on the lower driverside of the rear windshield, I noticed a small rust spot lurking out from under the seal.

I am thinking that this is likely one of my problems.

I am going to post some photos of these mentioned problems shortly.

Off to figure out how to change the antenna seal.....