Author Topic: Leaking Cabin? Found the problem, finally.  (Read 5056 times)

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Leaking Cabin? Found the problem, finally.
« on: 02 July 2005, 07:04 AM »
For 10 years my car had a severe problem with water leaking into the cabin during/after rain. The water wouldn't be obvious until the carpets began to smell.

I've had the car for a 18 months and within a few weeks I found where the problem was. The previous owner (my father) had a few mechs try to sort the problem out by smearing silastic into every crevice, the firewall, windscreen etc to no avail.  Consequently the carpets were tossed and some insulation.

During an attempt to rid the car of silastic and clear silicone residue I stumbled across something phenomenal.  Pretty obvious to the more experienced perhaps but at the time it was a huge discovery.

I was washing the car one day with windscreen wipers and fresh air intake grill removed.  The area was full of detergent suds when I opened and then closed the front passenger door and noticed the suds belch out of the well.  It makes sense that closing the door would cause pressure to push back through the air intake but whilst clearing the suds water started to flow inside the car and eureka!! there it was.

A lap join had rusted with old putty cracked and missing.  The area was hard to get to even with the heater hose removed.  

Refer to the pics, 5 in all.

I rubbed the area back by hand with wire brush, sandpaper and vacuumed.  Used some anti rust, cleaned dry with a cloth.  Sprayed affected area with etch primer then with gloved hand applied urethane to the area.  The join now, although hard to see, is well built up and had urethane forced into the gap of the join.  The whole well then got cleaned and sprayed with a matt black.  The grill and wipers were polished with a dremel and you may notice after all that effort I forgot to clear the silastic off the grill below the windscreen.

Anyway, it was Jan 04 when I did this job and haven't had a problem since.  Don't know if this is a common problem, feel free to comment or make suggestions.  Cheers.


« Last Edit: 07 May 2006, 04:07 AM by oscar »
1973 350SE, my first & fave

Mforcer

  • Vintage
  • ***
  • Posts: 973
  • Freedom Fighter
  • Location: Sydney, Australia
Leaking Cabin? Found the problem, finally.
« Reply #1 on: 02 July 2005, 06:50 PM »
Great post!!!! I too have a leak (I think I do anyway - it has been a while since my car has seen rain and I have tried to have it fixed a few times). I now want to give that a try too.

How do you remove the air-intake cover? Any other tricks I should now about before attempting this?
Michael
1977 450SE [Brilliant Red]
2006 B200

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Leaking Cabin? Found the problem, finally.
« Reply #2 on: 03 July 2005, 05:46 AM »
I'm assuming since our cars were put together in much the same way that my problem may present itself in other cars.  I remember a few years ago whilst visiting my folks the car was outside and was hit by one of those 1-inch-per-hour summer storms.  The next day both rear and front carpets were soaked.  Any other time, a small shower would let water in but was never noticeable.  I wish I had looked harder way back then before the carpets were wrecked.

As far as the air-intake removal; remove the windscreen wipers first.  Only one nut each, pretty straightforward just don't lose any washers.  

With the hood open, remove the rubber weatherstrip/seal above the firewall by pulling it upwards.  See pic.  There'll be four fasteners holding the intake grill to the body.  Styria wrote in another thread that if original there should be four plastic clips/studs.  By the sounds of it they're not meant to be readily removed.  If you've got those plastic clips I really don't know how to remove them. I've never seen them and my car has had poorly fitting screws in place instead.  More on that later.

The only other place the grill may be attached is under the rubber windscreen seal which may have some sort of adhesive.  Try and carefully pry the rubber up and away from the grill.  Otherwise you should be able to lift the grill from the front and slide towards you.

As far as putting it back together I wanted something more convincing than the four screws previously mentioned.  Having no idea what the original fasteners looked like, I've kept an eye out in hardware and auto shops for something to work better.  Here's what I found.
 .  
These ramnuts by ramset are ideal.  I've only put one in tonight after having bought these some time ago, and finally decided to try one out, and it works well.  The only mod I had to do was expand the hole with a 9/32" drill bit and then I forced the nut into it.  The grill's hole is placed over the inserted nut then the screw inserted and tightened.  The nut expands as the screw is tightened and there's no way the nut will budge.  When I do the other three, I may go a drill size slightly larger but less than the 8mm nut.
« Last Edit: 07 May 2006, 04:16 AM by oscar »
1973 350SE, my first & fave

Tomi

  • Classic
  • **
  • Posts: 180
  • Location: Finland
Leaking Cabin? Found the problem, finally.
« Reply #3 on: 04 July 2005, 03:01 PM »
This is a good hint. I had a problem also with water leaking in. The right side firewall is also quite vulnerable. I had a problem around the hood release wire and below the fuse box. I ended up just drilling a whole to the wheel well from above so that the rain water could just go directly down and filling the underneath of the fuse box with sealant. Now its OK
MB 450 SEL -80 (oldtimer for the class)
MB E220T -95 (daily driver)
MB 230E -82 (a present for my son)

andrew

  • Newbie
  • Posts: 2
Re: Leaking Cabin? Found the problem, finally.
« Reply #4 on: 23 April 2006, 02:02 AM »
Hi guys i have had my w116 for nearly 4 yrs and the drivers side is my main problem the carpet is in the boot at the moment.  so i can keep the floor dry with a towl. water runs ( or seems to) down the rhs then across the floor. I have just posted else where about the need to replace the lhs sill panel because its rusted out. car is too good to scrap. I have spent to much on suspension etc to give up now. when is enough!

AMG69

  • Classic
  • **
  • Posts: 485
  • AMG
  • Location: Lying back on the couch dreaming about the old 6.9!
Leaking Cabin.....
« Reply #5 on: 22 August 2006, 09:16 PM »
I have read Oscar's tips and passed them on to the guys doing the body repairs on my car; they swear they have done exactly as Oscar had advised; I even printed the POST off with photos and gave it to them; they are as frustrated as I am; the windcreen is coming out Monday as a last resort but they dont think its that as when the put a hose over the wiper vent area water came thru into passenger footwell - water never touched the screen; SIGH.......any other thoughts or comments I can pass on??????
sigh....sitting back contemplating the next purchase..!

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: Leaking Cabin? Found the problem, finally.
« Reply #6 on: 23 August 2006, 08:56 AM »
Man!!! I wish I could come and take a look for myself.

It's just that what you describe with the water passing thru the vent into the footwell is exactly how my leak was pinpointed.  Just looking back thru my post and pics on my computer for any better shots I realised that something isn't made clear.  The lap join and rust was way up there.  I had to basically lie over the engine bay with my forearm two thirds into that area to reach the lap join and patch it up.  All my photos are basically taken from an acute angle over the driver's side fender zooming way up that vent area. Like this:
 

It doesn't reveal how far up you have to look.

If you were standing on the passenger's side of the bonnet, facing the windscreen, looking down at the small panel between the wipers and the side fender, the problem area would be approx 4" in from where that panel meets the side fender.


See what I mean, prick of a spot.

To eliminate this area as being the problem, I'd suggest blocking it at the area under the small panel right where it meets the grill, making it watertight then see if a hose makes a difference.  How to block it up?  Expanding foam is my only suggestion, it could be removed easily afterwards.

Sorry for ranting, it just sounds too damn similar to my problem.  All the best! Good luck!
1973 350SE, my first & fave

AMG69

  • Classic
  • **
  • Posts: 485
  • AMG
  • Location: Lying back on the couch dreaming about the old 6.9!
Re: Leaking Cabin? Found the problem, finally.
« Reply #7 on: 23 August 2006, 06:26 PM »
Thanks Oscar!! I'll report back.....
sigh....sitting back contemplating the next purchase..!

cipha

  • Enthusiast
  • *
  • Posts: 25
Re: Leaking Cabin? Found the problem, finally.
« Reply #8 on: 23 August 2006, 10:03 PM »
For the Australians:  a visit to my local Repco store last weekend found that they have plastic 'rivets' in packets of ten for just a few dollars.  Just right for the job and they are in black!

To remove the old items, simply push into the centre and the plastic centre pin will move away from you enough so that the entire item can be pulled out.  Just remember this is only a plastic rivet.

When ready to reinstall the grill, place into position and push the plastic rivet back into the hole!

As for getting into the space, one really should have an agile child handy because the working room is tiny in there.

oscar

  • W116 Addict
  • ****
  • Posts: 4,043
  • Location: Riverina, NSW, AUSTRALIA
Re: Leaking Cabin? Found the problem, finally.
« Reply #9 on: 24 August 2006, 07:35 AM »
Hi cipha,

I've seen those displays with clips, nuts and washers etc but haven't looked for a replacement for the air vent grill.  I've still got the single ramset grommet in one hole and three cheap screws.  I haven't touched the area since I did the work but next time I'm in an auto shop I'll look for them.  From memory there's a lot of clips and fasteners there to chose from on those stands.
1973 350SE, my first & fave