Front quadrant leak - onto my passengers' feet... - PeachParts Mercedes-Benz Forum

DrLou · #1 12-08-2014, 01:59 PM

OK, needing to collect experience and expertise here...

'83 model 126 (300 SD) has developed a water leak which drips into the passenger side (drive side right) footwell. The drip occurs from a point just to the right of the glovebox.

The right side 'catch basin' appears to drain - ( but perhaps not fast enough? Clogged? )

Other note: The windshield was replaced 10+ years ago, and has never leaked. However, I've now noted that the windshield's lower protective sealing bar (name?) (it's a rubberized joint cover thingy covering the lower edge of windshield) is coming unglued on the right side.

Before heading out into the freezing cold to start disassembling everything, what should be the areas of focus/concern? Anybody else run into this?

shertex · #2 12-08-2014, 02:13 PM

Does the leak occur regardless of whether the car is sitting or moving....or only while moving?

leathermang · #3 12-08-2014, 03:26 PM

So we are assuming this is related to RAIN ?
Catch basin.... so that is somewhere sorta under the windshield wiper area ?

DrLou · #4 12-08-2014, 03:48 PM

Yes, this is related to rain* - and only in pretty heavy rain, or in snow melt. I suspect it's been leaking for some time now, if a bit less - even imperceptibly - in lighter rain.

Do the windshield catch basin wells drain into some sort of container underneath? - I've never disassembled this stuff...

leathermang: Yes, there are plastic-screened drains in each corner, on each side of the firewall; these are essentially right under the back of the hood. These are famous for trapping all kinds of crap - like the leaves from the monstrous oak in our back yard. I've been pretty good about keeping these drains clean, however.

* I should have been explicit!

leathermang · #5 12-08-2014, 03:52 PM

I think the lack of cleaning out the catch basin wells....... right under the springs for the hood.... is the source of much of the rust in Mercedes... at least the 123... just in front of the door .
so cleaning out that water ' exit' would be the first thing.. a long tube attached to a vacuum cleaner perhaps... or blow it out with air compressor....
then temporarily spray Fluid Film there to hold the rust till you can decide how to fix the situation....

Dan Stokes · #6 12-08-2014, 03:59 PM

If it's anything like 99% of the other cars in the world it'll have a sort of 1 way rubber valve at the bottom of the "catch basin". If you pick up a leaf or any other obstruction it'll plug and hold water. Reach up from underneath and slide a screwdriver up into the rubber valve. You'll probably get a rush of funky water out of it. It's best if you can pull the valve and rinse out the basin so you can get the chunks out of there then reinstall the valve. The reason for the valve is to keep junk, critters, etc. from crawling in there.

NOW - if you look from underneath and see rust you have a different issue. They CAN rust out such that the water runs directly from the windshield base to the passenger's footwell. Still fixable but refer to the various "Body Work" threads.

Dan

DrLou · #7 12-08-2014, 04:05 PM

Oh, there's definitely rust - around the exit of the swaybar...

Compressor cleanout was to be next step anyway - I just wanted to confirm my suspicions that it was likely the basin port getting clogged.

More important (and expensively) to see how I can be sure it's not the windshield itself leaking in any way...

leathermang · #8 12-08-2014, 05:51 PM

There are some very thin liquids ... in tubes I think.... designed to seal around windshields.... how long they last I do not know... but you can reapply....

toomany MBZ · #9 12-09-2014, 08:13 AM

May be a failed windshield seal, happened to me, but at the top. MB used a trick (imagine that) seal, a gasket with two wires, set the gasket in place, apply 12v to melt the seal in place. My new seal/gasket and as it turned out, new windshield is held in place with "goop" of some kind.

But, check under the battery tray for any rust through.

leathermang · #10 12-09-2014, 08:20 AM

That particular ' goop ' is specified in the FSM.....

toomany MBZ · #11 12-09-2014, 08:25 AM

Yeah, butyl tape.

funola · #12 12-09-2014, 10:13 AM

An easy way to find water leaks is to stuff pieces of white (more easily to see stains) bath towel and stuff it under suspect leak areas (dash and windshield, under battery tray of interior etc), wait for next rain and inspect.