looking for help with finding leak in 84 300td. After rain water will collect in right rear footwell it does not come door seals or window seals. it seams to come from under tha back seat. But the trunk carpeting is not wet. car is in good shape no rust in the area. thank ful for any sugestions.

On the sedan there are some inspection ports for the shocks in that area...not sure on the wagon, but it is worth a look.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

May also be from the sunroof. There is a drain on each side, goes down the "B" pillar to empty under the car. If the drain plugs, the water ends up somewhere else, including in the rear footwells.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

If you haven't, check your front passenger floor for water. Water tends to run back to the rear floors from the front. If your carpet pads are soggy, the water is coming from the front, not the rear.

Which means either a leak at the windshield gasket, or more likely a leak at the seam in the hood hinge area or battery box area.

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

This was my problem. My car was rust free from Texas, except a nice 4 inch hole under the battery. I still have a dry stream of battery acid running down the passenger floor boards into the back. The hole has since been fixed.

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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

Check windshield seal. Mine is fried and will make a nice wet passenger floormat after a good torrential downpour.

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1982 300TD 210K miles ("The Replacement" aka "The Anvil") - SOLD
1979 300SD 245K miles (never ending project)
2007 Pinarello F3:13
1995 Ducati 916 (SOLD, sniff)
1999 Ducati 900SSie (SOLD)

I have 2 with windshield seal issues, and both puddle water in the back. Easily the most common cause.
You also have drains right under your hood hinges that get clogged with leaves and dirt and stuff. Battery tray leak is on the list also.......
Usually you can find wetness in front floorboard outter corners which lets you know it then made it's way to the back.
Good luck, it's maddening sometimes.
BTW, with the dash out it is really easy to see the windshield leaking. Ask me how I know.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

check the wells that the hood hinges are mounted in. there i s a drain in them which gets clogged easily. also, under this drain is another one which drains into the wheel well. it can be found undereath, to the rear of the tire. a rubber boot about 1" dia, 4" long. on my car this was also clogged. that, coupled with a small rust hole under the battery tray = wet floor on the pass. side.

maybe a good idea to pull the battery and tray, just to have a look and clean it up. 10mm socket and ratchet is about all you need, once the batt. is unhooked.

these cars, the rear floor is lower than the front, as there are air ducts under the front carpet. however, if you peel up the carpet when its wet, you should be able to determine if it is coming from the front.

also, on these wagons, the sunroof drains way at the back a arm. if you stand at the back of the car, look behind the rear side window trim. you can see the drains. i sprayed mine out the last time i washed the car.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

I have a 1985 TD with the same problem. My windshield has been replaced since I owned the car and I still get a puddle in the rear passenger side. I haven'e checked under the battery, or really anywhere else, but I feel sure it is not the windshield. The meatballs that installed it did not do a very good job, but they used enough caulk for two windshields so I think they got it all sealed up.

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Doug

1987 300TD x 3
2005 E320CDI

Definately look under the battery tray. Both of my 85's had rust issues under the battery that caused the rear passenger floor to get wet. Other wise these two are rust free. My two rusty 123's dont have any rust under the battery. Go figure.

Take a look at the 'hinge wells' under the hood. I had a hole near the fuse box and lots of water in rear floor. I patched the hole and added another (stock unit is iffy) drain.
Winshield leaks should yield small amounts of water. I had around a gallon after a good rain.

There is plenty of proof that rust is a big problem in the areas described. There is a seam in the hood hinge well that also works its way open with high mileage, rust or no, and my current opinion is that it is probably a good idea to butter that area up with your favorite sealant. Check those drain holes regularly, and reach inside the wheel well to pull the plastic drain out a bit to get the crud in there unstuck. Do this regularly. I am glad they put the drain holes there, but this was not German engineering at its best!

I have a very non-rusty wagon, and I still have a leak on the driver's side. I have pulled the battery, and tray, sanded primed and painted under the battery; I cleaned, scraped and cleaned again, and used rain gutter sealant ( great stuff) in the hinge well area. I checked and cleaned the cowl vent areas and drains. My sunroof drains seem to work fine.

I also just had my windshield seal replaced (robbed for $160 by an outfit that wanted to sell me new glass and did not want to put the metal trim pieces in, the topic of a whole other post) so there is new rubber there. MB FSM apparently says to put sealant on the vertical sides of the glass, not around the whole thing. There is a school of thought that says the sealant hardens to a flexibility different from the gasket rubber, and causes leaks. The glass tech agrees, saying the new rubber will fit itself to the glass and frame, so no goop in there now. I think my next move is to follow the FSM procedure and see.

The water buildup is less now, only enough for the front pad to get soaked if the car is sitting, but I am not sure I have replicated the long drive in heavy rain which seemed to produce the most water.

It is EXTREMELY aggravating to find a solid rust-free body only to have to keep pulling the carpets and drying the floors. Winter means sometimes I am resting my feet on frozen carpet pads, not fun!

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

Also, as far as the windshield is concerned, it's a good idea to check and make sure the drains on the sides of the car are screwed in properly. I'm talking about the drains above the doors that channel water down along either side of the windshield.

When my windshield was replaced, they only put two of the three screws back in on the passenger side. The crud washing down eventually ripped a hole in my seal. This leak was fixed when I got that third screw back in.

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Ralph

1985 300D Turbo, CA model
248,650 miles and counting...

had similar problems as you ...wet back well.pulled carpets found hole at the base of the b- pillar.I recently purchased a new fender(pass.) and after pulling the old one,I found significant rust under the bottom of the fender.the very front of the frame rail? was rusted away.formed up some metal and fixed.while fender was off and getting painted,the new patch got very rained on....no water in the back.yay.hopefully this will help you find your leak.good luck.

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1984 300D turbo 155k

www.interactivepainmanagement.com

great advice as im having some of the same problems. in my case the drivers side is far worse. i just got my 300DT and after a couple downpours here in boston its downright swampy in there. bummer.

is there a good way to dry out the under floor area after removing the carpets? my car is fairly rust free (Texas) and id love to keep it that way. a good bit of water has gotten in between the floor pans and the plasticky under carpet material (technical term).

is there a summary somewhere of where the potential problems drains are (pics)?


-dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car