My trunk leaks/got a leak in me boot
 

My '81 300SD, 126 of course, has a leaky trunk. Can't tell exactly how the water's getting in. The back window and rubber could use replacing but this rig's not worth that sort of investment, not yet anyway, so I carefully applied Sikaflex to both sides of the rubber. When I open the trunk, water has condensed on the underside of the trunk lid, unless it's somehow leaking directly onto that surface, under the weather stripping.

Any experience with this?

I also have an 81 300SD which had a VERY wet trunk when I bought it. Now keep in mind, this is my first older Mercedes deisel and I knew nothing of the chronic ailments of this car let alone the existence of this forum! So, first I installed a new real window seal, it helped a little. After that, I climbed into the trunk with a flashlight and had the wife hose down various parts of the trunk area. Low and behold, very leaky tail light seals! So, I removed both lights, discarded all old seals and cleaned all surfaces. Then came the black silicone sealant! Keep in mind, this car is my driver, I wouldn't do this to a nice car. Well the sealant worked wonders, my trunk is now dry as can be!!!!

You sir, are a gentleman and a schoolbus, uhh... I mean, scholar. I was thinking about trying the getting in the trunk for a good hosing routine myself. I'll check out the tail-light seals first. Makes sense.

Cmac, glad to pass along the small amount of Mercedes knowledge I have accumulated so far! Let me know what the outcome is.

Don't forget the taillights has 2 seals. 1 between the light assembly and the body and another between the lens and the black plastic. I know because I had to do them twice.

We had a puddle in the well on the passenger side and I found that the drain hose from the gas flap had plugged. Reamed it out and it appears the problem is gone. It's easy to check, open the gas door and pour a cup of water to see if the drain works.

Excellent advice. I'll post results on this thread before too long.

I use my Benz for work a lot and I like the big trunk for tools. Don't like getting them wet, though.

I tried hosing the lighting area copiously with some paper towels inside to indicate if water had flowed. Doesn't seem to be it.

One thing I've noticed, whenever I open the trunk (during the wet months) there's a lot of condensate on the underside of the trunk lid. This will be happening even if the rest of the trunk doesn't seemt that wet. In the bottom edge of the trunk lid is a small opening you can sorta get your fingers into and it usually has standing water. This is probably some of the condensate that just runs down into the space.

I'm also thinking it might be indication that water is leaking in via the holes that attach the "300 SD" and "DIESEL" and 3 pointed star insignia, though I might be grasping at anything here.

Take a close look at the trunk seal. One of mine has a crease in it. Kind of looks like some previous owner may have routed a CB antenna cable or something diagonally across the seal. I am going to have to replace the seal in order to cure the wet trunk problem. This one also has dampness and evidence of rust on the bottom of the trunk lid.

Cmac, apply a thin film of petrolium jelly to the trunk seal and close it.Now open the trunk and see if the jelly transfered to the lid. A neat little trick!

now on the
 

climbing in the trunk with your wife hosing down the back end of the car.... just be sure you havent pissed her off anytime in the last year or so.

tom w

I had an 82 300SD and it leaked into the trunk. It was the rear window molding. I did a lot of searching for a good price and found it for about $65 several years ago.

Good rule of thumb: if you lift up the windshild rubber and it doesn't snap back ... it should be replaced soon...by how fast the rubber returns is a great gauge to how old the rubber is.

If you decide to do it, be very careful of the rear window defogger wires going through the rubber window molding on each side. The electrical connections are VERY easily broken, very easily .... don't ask me how I know this.

The rear tailights housing also are known to leak. Also check in the trunk wells for missing plugs and for junk accumulated in the sunroof drains.

Haasman

My trunk seal looks a bit rough. When I got it, part of the metal rail the seal is attached to had rusted out. I fashioned a piece of thin steel to bridge the gap and attached it with mucho JB Weld. It's hard to figure the trunk seal. Even if it's not perfect, the little channel around it ought to drain out most all of the water. The trunk on my Bimmer is almost loose around the seal -- doesn't seem to close super tight but it hardly leaks at all. Just a few drops in one spot.

I went to see a 300SD that looked real good in the Craigslist picture. Looked good up close too but had many little bugs. The owner said he was a mechanic.... well, maybe, hard to say. His trunk was pretty wet also. He'd replaced the trunk seal and there must be some tricks to it he didn't know about. At the two sharpest turns, the stuff kinda puckered out. Definitely not the way it comes from the factory.

Not to be a wet blanket, just a word of caution.

THAT is a neat li'l trick. I'll try it.

:D :D
HONEY!! C'mon baby... no really, I like your hair like that. I was just trying to make you laugh. No, really I was. And that dress you wore to the party the other night? Smashing! Really smashing! Now come on sweetheart, this was funny for the first 5 minutes...

Honey? HONEY!!

There are very few places on a car where petrolium jelly should/could be used. Do not use it on or leave it on ANY rubber parts. It will eat it fast!

Use petrolium jelly on your ashtray glides.

In my experience, the trunk seal rarely leaks. If you want to test it, use the Dollar Test (also good for refrigerators). Close the trunk on a dollar bill. If it is easy to pull out, then either the seal is bad or it simply may need an adjustment.

Lift the window molding: If it doesn't snap back it's bad.

Haasman

Whoa, thanks for the tip.

I'm thinking my problem might be the sunrood drains. There are watermarks now and then on the ceiling liner. I'll dig into it tomorrow.

You managed to replace the rear window molding yourself? How tough was that? I was under the impression that it was one of those tasks that required special knowledge and tools to pull off.

My rear window defroster only works on the top half. Oh man, if I could somehow stop the leak and get the entire window to defrost/defog, THAT would be a good day.

It isn't really that hard if you know how to do it.

If your rear window is only defogging on the upper half of it, I beleive that means that the connections are broken. You might be able to repair that using a liquid solder but .... very iffy.

The key to the rear window molding is handling the aluminum trim carefully and not pulling the wires off the window sides.

Installing isn't hard if you know how to install auto glass using a 1/4 nylon rope, lots of patience and silicone spray.

Haasman

i have had good
 

luck cauliking tired windshield front and back with black 100% silicone. clean joint with alcohol and caulk a small bead on the joint between the glass and rubber. i sometimes cut a small part of the edge of the rubber off about 1/8" and form a groove for the silicone.

i 've been doing it for about 20 years first time with my 51 caddy. sometimes i have had to do it after a new gasket is installed to seal it up.

tom w

Oh man, that's what I was afraid of... I don't know about the 1/4 inch rope method or even lots of patience.:D

If only the car was closer to a cherry, I'd buy a new rear window and have it done professional-like. I could just see me breaking the wire to the part of the window that does defrost... and then not being able to get it back in.

Hate to be so pessimistic...

I tried that already with black Sikaflex but it didn't seem to work. Now I see some of the Sika is degrading in the UV.

I was thinking silcone might be better. This car would be just fine w/ a slightly big and crude looking silicone enhanced window bushing.

My dad used silicone once on a mid 70s Mazda -- worked fine.

I'll try it. I discovered a leak today after a rain in the trunk right under the rear window. Don't know why I couldn't find that before.

I also had a leaky trunk on my 1986 300E ( 124 series ). I thought it was the rubber trunk seal, but instead found that the weld between the inner panel and outer lid was no longer sealed. That allowed water to enter the lid itself and accumulate in the rear. Upon opening the lid, water would spill out from the lid.

So caulking that weld all around the trunk lid worked well for me.

- michael

Good tip, I'll check it out.

I had a wet trunk problem on the wifes Caddy several years ago. One of the sunroof drain tubes was not draining properly and dumping water in the trunk. Check yours closely, look for cracks in the rubber tube and make sure it exits the trunk properly. I farted around for over a year with this, constantly taking it in to the dealer. They never did find it. After about the 6th visit, I decided to find it myself, which I did in 20 minutes. So much for Mr Goodwrench!

I'm sure it's been mentioned, but shut yourself in the trunk and have someone spray with a hose. Start at the lights then move up to the antenna, trunk, rear window and sunroof. If it leaks, you'll see it. Oh, and take a flashlight with you!

Er... Does this mean the entire window rattling in the opening isn't a good thing?

It goes thumpa thumpa while I'm scrubbing it on the inside.:eek:

Michael

I took my 1971 250C to a glass shop and requested a quote for new glass and rubber. He pretty much refused to give me a quote but did offer to try to seal it for me.

He gave me a plastic tool and sent me home with instructions to clean the gap between glass and rubber with a blast of water from a garden hose.

When I returned, he used an industrial caulking gun loaded with bedding compound to run a bead between glass and rubber. He shoved the nozzle well under the rubber and filled it up. Afterward, he hosed it down with foaming glass cleaner and wiped away the excess. When he was done you couldn't tell he'd done it, it came so clean. I figured if I tried it I'd have compound on the roof, hood and me!

He refused payment as he didn't "want to be married to the job".

Hasn't leaked since.

Michael

Uhh.. lemme see, it would cost me how much to get up to Des Moines? :D (Long time Seattle - former - resident here)

Damn, I hope you gave him a six-pack or something. That's some wild stuff.

Any idea what the bedding compound was?

cmac,

I think it was this stuff,

"3M™ Auto Bedding and Glazing Compound, 08509, 1/10 Gallon (US) Cartridge, 12 per case

Non-hardening, pliable, water-resistant, medium-bodied sealer for sealing auto seams and between windshield rubber and car body. Can be used as a supplementary sealer for auto glass installation.


Buyer's Part Number : 08509
3M Id : 62-5562-5209-6
GTIN(UPC/EAN) : 0 00 51135 08509 7

Remains permanently soft. Has non-sag consistency for vertical and overhead applications. Cleans up with dry rag."



Probably get it at auto paint stores and maybe NAPA.

Michael

You the man.

This is ironic. When I opened the trunk on my newly acquired 85' Mercedes, I too noticed some moisture inside the trunk lid on Thursday morning. It had came a very heavy rain storm on Wednesday night. The trunk seemed very dry however. I could not feel any wet spots. I have not driven it, because I have not had my plates transferred, so the car has been setting. Now what is interesting is that my rear window has condensation on the inside of it. It was sunny that next day, then cold again that night. I have not noticed any "musty" smells inside of the car and there appears to be no leaks inside of it (passenger cabin). Could that just be where it is air tight and the temperature change caused it, or is it likely that my trunk is leaking somewhere. I have been reading things like sunroof drains, taillamp gaskets, fuel filler door drains, etc. I am thinking perhaps sunroof drains. It looks to be sealed good. How could water drip down in there? Where are the drain outlet for those at? These cars are totally new to me.

Thanks!