Hi,

I posted a similar question in the diesel discussion, but water flow and movement as well as mitigation of standing water and protection from rust is likely more suited for this forum area.

I had this (outside pic):



So that rust shown on the outer side of the driver's floor/wheelwell is shown as a repair here (from the inside):



It has a few small holes (not really visible) in the seam that is welded. Right or wrong? Perhaps someone can comment... I dont care so long as it is not an issue; the repair is very strong, but the weld is not 100% all the way around, though the "holes" in the seam are extremely tiny. I figure once I get to the bottom of all of this, Ill be painting the whole floor in POR or rust encapsulator anyway, so the tiny holes will be sealed with POR patch or similar, but for now they are open, and so water will come through them when...

The repair is fully sealed and undercoated on the outside, but when water runs through this:



Water will come through the few weld holes on the inside - itll run right in.

The question is, what is the standard MB mitigation scheme for sealing off and removing water that flows into that hole by the sway bar???

Obviously this mitigation is not present, thus why I had rust there to begin with. Rust repair is only as good as getting to the root of the water ingress problem, so any insight into how to seal that sway bar area, and why it is causing me troubles in the first place, would be most appeciated.

Thanks!!!

JMH

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

5 months later...but better late than never.

First option: if you have access to a MIG welder, shine a light from the bottom to identify where the pinholes are. Look from the inside (obviously). Mark with a pen. Just make spot welds where the holes are.

Second option: Rust/grease remover + POR15 (or similar) + seam sealer + rubberized undercoating. Clean the bottom with the rust and grease remover, apply POR15 to both sides. When POR15 is dry, seam seal it, around the edges of the weld and on top. Allow to dry and spray rubberized undercoating . Dont go cheap on the undercoating. Go 3M or search autobody forums for other recommendations. If you have a grinder, grind down the top of the welds (called "prouds" in bodyshop speak) until they are about 1/2 way down. No need to grind flush to the body.

Hope that helps,
bob