[Digmenow]

In another thread, I had an electrical issue which was eventually discovered to be caused by water that had entered the passenger side floor and corroded a connection. That thread is here and explains what took place up to this point.

FIXED! 2005 S500 4Matic: Key will not turn in EIS


This thread picks up from the above thread as I try to save the car from suspected reed valve blockage.

While discussing the outcome of my previous issue with my indie, he strongly suggested drilling a drain hole through the plastic electrical cable channel that contained the corroded harness connection and out through the bottom of the car. I have my doubts about the ability of water to drip from a hole in a plastic box directly into the additional hole in the steel car floor to the outside. I'm imagining a very soggy outcome but...is it really a dumb idea if it works?

I'll begin with the usual suspect, that damned drain and if it is indeed clogged, I'll simply have to be more vigilant in the future.

 

[wallyp]

I most certainly would NOT do that! It might be possible that you have actually fixed the problem - but in most cases, moisture-caused corrosion is harder than that to fix.

Quit screwing around with the drain. The suggested fix - from Mercedes Benz! - is to drill a hole near the bottom of the plastic plenum to drain overflow from a clogged drain out and down to the ground.

BUT once water gets into the car and flows back under the carpet, it is absorbed by the thick foam carpet padding, and there it releases moisture forever, causing continuing corrosion and major problems. There will be no sign of water on top of the carpet! The ONLY permanent cure is to pull the carpet and padding from that side and thoroughly dry the carpet and the padding underneath, and to disassemble, clean and treat every electrical part under there, all the way to, and inside, the rear SAM. If you don't do those completely and correctly, your car will continue to deteriorate and eventually die.

If you can see no trace of moisture in the padding, you might have the problem cured - but it usually isn't that easy.

 

[tusabes]

Yep, the recommended fix by Mercedes is to draw a hole in the plastic reservoir in the engine compartment, so the water can never pool so much to leak into the cabin

 

[Digmenow]

Okay, then.

I pulled up the back seat and lifted up the carpet a bit in the rear footwell and the padding was dripping wet on the bottom. The electronics under the seat appear to be dry at this time. There is no standing water in the floor pan.

Some fella that appears to know what he's talking about over to another M-B site said this is how you get the carpet out to dry it. I guess that's next. Also I'll be popping open the plastic channel for the cable to dry that out if necessary.

Unbolt front passenger seat

lift up rear seat bottom cushion using tabs at each end

after that the carpet simply lifts from the front under the dash all the way back

Meanwhile, under the hood, I took the screen off. The valve is gone. It's just a hole. I poked a stick as far down as I could and it came up wet on the last three inches. It does NOT go through to the bottom of the car so I have to look into THAT.

I will be drilling a hole in the air box as an emergency drain.

 

[tusabes]

The thick foam under the carpet absorbs lots of water and the only way to dry it out is to take out the carpet with its attached foam, squish all the water out , then use dryers to fully dry it . You can’t dry it from the carpet top

 

[Digmenow]

The thick foam under the carpet absorbs lots of water and the only way to dry it out is to take out the carpet with its attached foam, squish all the water out , then use dryers to fully dry it . You can’t dry it from the carpet top

It'll be chilly tomorrow but I'll pull the front seat and the carpet as best I can in the morning. I found a fella who is selling 3 of these at a VERY good price on FB Marketplace a bit down the road so hopefully, by mid afternoon, 1600+ CFM will be blowing against the underside of the foam from whichever one I buy.

With the carpet out of the way, I'll pop open the plastic wiring channel to dry out the inside and clean up whatever doesn't belong. Electrical cleaner spray will be liberally applied after everything gets brushed/wiped down.

 

[cowboyt]

Oh, you've got wet foam? Yeah, been there, done that. I'm afraid you've got to pull that carpet completely out of the car and let it dry. There's no shortcut way to do it. When it happened to me, it took several days out in the hot summer sun. Now, our summers are a bit more humid than in, say, Arizona, Nevada, New Mexico, or Southern California, so it may take a day or two less in those locales. But it's still going to take several days even in summer. Now that it's winter, you're looking at a week, minimum. This is with you helping the drying process every day or so by squeezing water out of the foam.

Like I said, been there, done that. It ain't fun. But on the positive site, you actually will be able to access the whole floor, including all the wiring and such. You'll be able to make sure everything's clean, dry, and ready to rock for another 15-20 years. Be sure to get EVERYTHING electrical down there, including both left and right CANBUS connections.

And while you're at it, you might as well take some warm, soapy water and scrub the carpet clean, since you've got to dry it out anyway.

 

[Digmenow]

I am unable to disconnect this vacuum line that attaches to the front of the passenger front seat. It's the last disconnect before removing the seat from the car. If anyone has a hint, I'll give it a shot.

Meanwhile, I was able to unbolt and pull the seat forward enough to feel under the carpet as far back as the floor vent and everything is dry.

Starting from the rear however, the right rear passenger footwell foam is soaked and I can't remove it until I get the front seat out. The left rear footwell feels dry.

I tried squeezing some water out of it but it splashed onto the electrical channel and I didn't want it to get wetter than it already is or was.

I pulled the carpet off the footwell floor and blocked it up about 4 inches off the floor in the whole area. Then I set up a 2250 CFM carpet dryer (the Facebook seller sold me a heavier duty fan at the same price!) blowing directly on the foam. It's similar to professional units and it's creating a healthy, steady wind against the foam and the floor area. I'll check it again in 2 hours before it gets dark to see if there is progress and report back.

The cool weather is working against me and it will probably be slow going at a sunny 40° F. They're calling for similar weather tomorrow so 8 or 9 hours should put a dent in the drying process. Rain is expected on Thursday so everything will be on hold. The sun returns Saturday and Christmas so if it still needs it, I'll continue to use the blower.

When I feel that it is dry, I'll investigate the wiring harness channel in that part of the car to see if anything needs to be cleaned.

One last thing for the moment, having poked a stick down the drain pipe to clear out any debris, I poured a few ounces of water down the chamber through the (currently missing) reed valve and the water dribbled out beneath the car as it should.

 

[Deplore]

I am unable to disconnect this vacuum line that attaches to the front of the passenger front seat.

Ever work on american cars, and have to disconnect the fuel lines with the special tool?

Same principle. Spray a bit of wd40 or silicon spray to lubricate it beforehand so it doesnt break.

 

[Digmenow]

Ever work on american cars, and have to disconnect the fuel lines with the special tool?

View attachment 2797651

Same principle. Spray a bit of wd40 or silicon spray to lubricate it beforehand so it doesnt break.

That looks like just the ticket. I tried using dental picks but I needed 4 hands. A quick search yielded nothing but I'll keep looking unless you have a link.

 

[cowboyt]

Those tools that Deplore points out? Good principle. I've tried those before, and unfortunately they didn't work too well for me on those air fittings. My guess is that I probably A.) didn't have quite the right size, and/or B.) was doing something wrong. So, I took one of those computer "roach door" things at the back of most desktop computers and bent it to shape, like this (thumbnails are clickable). Note: this is the replacement since I lost the computer roach door (it's a grouting tool for ceramic tile), but the principle is the same.

On the other side, I use a flathead screwdriver.

This combination does a good job for me unpopping those air connectors.

 

[Deplore]

A quick search yielded nothing but I'll keep looking unless you have a link.

Fuel line disconnect tool. You can rent one from autozone or something.

You shove it in, then pry it open slightly.

 

[Digmenow]

Fuel line disconnect tool. You can rent one from autozone or something.

You shove it in, then pry it open slightly.

This air line is VERY small. Maybe half the size of a fuel line or smaller.

I have to say that there is a significant improvement with just two hours of high volume blower air. There's a long way to go but I've got time and the less that I have to destroy through ham-handed disassembly, the better. Sad to say that the clips that fit over the ends of the seat rails on the floor did not fare well.

More this time tomorrow.

 

[tusabes]

The right rear corner of the carpeting that you have pulled up is the real problem area where the water gathers, so if you squeeze out that foam tightly with your hands, and use the air dryer, you might be able to get away with out, taking out the front seat

 

[pinkster]

Cut a piece of stiff plastic 1” x 2” . Roll the plastic to get it to curl, start with a corner of the plastic under 1 of the clips on the hose and work it around gently until it is under all 4 clips. The hose then undoes with ease.

 

[Digmenow]

The fan was turned on at 9 AM (I was feeling a bit lazy) and I just turned it off at 5 ish so figure 8 solid hours in mid 30's F temps with low humidity. The section closest to the fan (right rear corner) and moving across to the center of the foot well is dry to the touch. I pinched it pretty hard and only got a small damp spot.

Farther forward, however, is still wet through and through. I'll need to raise the carpet and padding higher off the floor so that the air moves under it better.

We're getting rain all day tomorrow into the next morning so I'll try relocating the fan so that I can close the door and continue to blast air on it. If not, it'll go on hold until it dries up outside.

I am feeling encouraged that the blower will dry everything completely without removing the seat so I'll hold off on the air line for now. Expect another progress report around the same time tomorrow unless the day is a washout.

 

[Digmenow]

Well, that was refreshing!

It took a bit longer to finish up than I had expected. Cold weather, wet weather and then this held all of my attention recently.

The empty space on the concrete pad I put in over 10 years ago is where I took the interior apart, found and fixed my electrical issue...

...and here's what took its place over the last few weeks!

There was a short break during the construction where I was able to park the car inside for a day and put the interior back together. The carpet and foam underlay had dried completely thanks to the carpet fan and some moderate weather. I checked the left rear footwell and it had never gotten wet so all of my focus was on the right rear side. The fuse box and everything else under the rear seat was dry with no sign of previous water incursion.

Here's a couple of pics of the plastic channel running through the rear footwell. It was completely dry inside and there was none of that green crud under the wires like I found in the front footwell.

I reassembled everything and took the car down to the indie and he blew shots of air through the sunroof drains. Not sure if that helped or not.

I'll keep a close eye on the drain under the hood. I still don't know where the water came from.

It's raining as I type this so I'm open to any suggestions.

 

[Witek_M]

It's raining as I type this so I'm open to any suggestions.

Keep it in the garage.

 

[Arhippa]

Great news and great garage!

 

[Digmenow]

Keep it in the garage.

Why didn't I think of that?