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Old 03-31-2020, 06:22 PM   #1
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Location: Memphis, Tn.
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Rain Water Leaking Into Cab FYI (Long)

OK, Been fighting water leaking into my '92 cab on drivers side floor for a while and just thought I would post where I'm at now. (I did search this and other forums for info and found some, cowl vents were clear, etc.) Carpet removed, minor rust on floor repaired and the search begun. My Windshield was 10yrs old and cracked at the bottom and was hoping to wait on replacing it until I get the truck painted this summer, but I had to stop this leak. New windshield installed, no rust at all around frame, but there were signs of upper corners no longer adhering and probably leaking some. Great easy fix, well hard rain and still had water leak, much better, but not fixed.

I found some pinch weld seam sealer dried out and flaking on the outer firewall cowl, hinge area both sides. Removed what I could and put sealer on everything I could get to. We had some light rain and garden hose test, no leak thought I was there. Wrong, all day hard rain still leaking. Pulled left front fender, found more sealer crumbling, and a major contributor to the leak. The fender and hood mounting welded bracket has a gusset stamped into it with a drain hole and it was stopped up. There is also a pinch weld seam behind the gusset with crumbling sealer, so when the gusset fills up with water it gets into the seam and leaks inside. Cleaned the seam as well as possible but you can't get to all of it. I ended up using Loctite urethane to just fill up the void and cover all the seams I could get to. Probably not the most correct repair but I saw no reason for it not to work.

OK, passed garden hose test and even all day hard rain, no water inside. But I had to push it and used hose end sprayer full force inside the cowl area in every direction I could point it, and I got water inside, not much but some. With so many seam and panel joints inside the cowl with no way to spray anything in there, I used Rustoleum's liquid rubber, as it's paintable, on a brush and put several coats on every seam inside the cowl area. This was a pain as most of this you have to do with a mirror just to see where you are. This stuff dries thin so multiple coats are necessary. After curing, painted same with oil base enamel.

So far, no leaks with the garden hose or the 1 1/2" rain last night, I still have my fingers crossed. Just thought I would post this just in case anyone else is fighting the same thing.
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Old 04-01-2020, 07:05 AM   #2
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Re: Rain Water Leaking Into Cab FYI (Long)

If it works, it works. How was the rest of the sheet metal in that area? Any rust? That is a structural point, but I have done what you did on some vehicles that the seam sealer went to heck.

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Old 04-01-2020, 10:00 AM   #3
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Re: Rain Water Leaking Into Cab FYI (Long)

The sheet metal actually looked better than I thought it would, especially around the windshield, no rust. On the cowl portion behind the fender mount in the picture, very light surface rust only at the seam where the sealer dried out, but I really canít see between the panels, so I hope Iím good.
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