Author Topic: Major leak coming into drivers side floorboard  (Read 7718 times)

jtwoods4

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Major leak coming into drivers side floorboard
« on: 01 October 2012, 12:29 PM »
Today we had a very bad rain storm. The drivers side floorboard is soaked on my 1980 300SD. Any idea where the water would be coming from or how to fix this? It appears to be coming down the side of wall of the floor board.
1980 300SD

jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #1 on: 01 October 2012, 12:47 PM »
Just did a more detailed inspection and it appears to be coming down from under the dash, above the drivers left leg.  :-\
1980 300SD

s class

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Re: Major leak coming into drivers side floorboard
« Reply #2 on: 01 October 2012, 12:50 PM »
Probably a rust hole in the firewall behind the fuse box. 

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jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #3 on: 01 October 2012, 01:00 PM »
So I guess I need to remove the fuse box and inspect?
1980 300SD

jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #4 on: 01 October 2012, 02:58 PM »
Does anyone have a diagram that shows the location of the drivers side drain tubes? There may be a blockage but I have no idea where they are.
1980 300SD

Big_Richard

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Re: Major leak coming into drivers side floorboard
« Reply #5 on: 01 October 2012, 03:05 PM »
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« Last Edit: 21 January 2013, 03:01 PM by Major Tom 6.9 »

jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #6 on: 01 October 2012, 03:07 PM »
Hmmmm, so it looks like I have to remove the fuse box to pull back the insulative material on the drivers side. The passenger side is fine. Arrrg, anyone removed a fuse box?
1980 300SD

jbrasile

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Re: Major leak coming into drivers side floorboard
« Reply #7 on: 01 October 2012, 06:34 PM »
jtwoods4,

This is a chronic problem on 116's. If the water is coming from the left in the direction of the fuse box, it is possible you have a firewall rust issue. I had the same thing happen with my 450SEL.

See image below of what we found once the fuse box was moved.





Repair:












To remove the fuse box you need to take out all the panels under the dash. You will see  4 10mm nuts that hold the box to the firewall. Once those are removed you can move the fusebox far enough to inspect under the firewall insulation.

Repairs are tricky to do correctly but if damage is not too extensive I suppose you can seal any rust holes.

Good luck and keep us posted.

Tks

Joe


jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #8 on: 02 October 2012, 04:03 AM »
Very nice detail. Thank you. My car was garage kept and has 100k miles so I doubt there is a rust issue. Is there any other way water could be draining into the drivers floorboard. I have heard people talk about drain holes and darin tubes but I have no idea where these are located.
1980 300SD

Kjhall65

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Re: Major leak coming into drivers side floorboard
« Reply #9 on: 02 October 2012, 05:05 AM »
Could be the windscreen rubber.  I had that with my 115. It let a lot of water in during short trips in the rain.
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jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #10 on: 02 October 2012, 05:33 AM »
Interesting I will need to check that. How did you fix the issue?
1980 300SD

jbrasile

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Re: Major leak coming into drivers side floorboard
« Reply #11 on: 02 October 2012, 06:17 AM »
jtwoods4,

So was mine...but it can happen even on very well kept garaged cars.

Yes water could be coming in through the windshield gasket or the cowl drain hoses might be incorrectly positioned, they will dump water right on top of the steering column cover plate in the engine compartment. The drains are the two large tubes that curve down from the firewall near the brake booster, sometimes they are orange color.

If it is from the windshield, you need to replace the seal. If it's from the drains, just re-position them until no more water hits the above mentioned cover.

The best way to check where the water is coming from is to remove the panels under the dash, carpet and floor insulation. Take the car to a self-service car wash and have someone spray hi pressure water on to the windshield/cowl area while you check under the dash for leaks with a flash light, otherwise you will be chasing ghosts...

Tks,

Joe

Casey

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Re: Major leak coming into drivers side floorboard
« Reply #12 on: 02 October 2012, 06:51 AM »
I noticed water coming in at the hood release latch today as we had a lot of rain this morning.  I was surprised as I don't suspect there to be any rust whatsoever on the vehicle.  But  then I noticed it was seeping around the bottom of the windshield glass, running over the inside of the gasket.  So I guess I'll be swapping the gasket this weekend.  In the meantime I turned the car around so that it's pointing ever so slightly downhill rather than uphill and this seems to have stopped (or at least greatly reduced) it for the time being.

I also noticed there's some moisture in the trunk wells that condenses on the lid.  The darn trunk lining in the later models really hides this unless a lot of water gets in and pools up - I think I'll pull it out for now.  I need to order more rubber soon...
« Last Edit: 02 October 2012, 06:55 AM by Casey »

jtwoods4

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Re: Major leak coming into drivers side floorboard
« Reply #13 on: 02 October 2012, 11:32 AM »
Well I did some checking and the water appears to be coming in right next to the emergency brake pedal. The location in the engine compartment above the brake pedal is where the hood ring folds into. This is a little packet that water can collect in. Is it suppose to drain somewhere? See the picture below.

1980 300SD

Big_Richard

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Re: Major leak coming into drivers side floorboard
« Reply #14 on: 02 October 2012, 01:35 PM »
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« Last Edit: 21 January 2013, 03:01 PM by Major Tom 6.9 »