I searched the archives, but found nothing.

My '64 F-100 has a nagging habit of leaking when it rains, whether it's going fast or sitting still and just looking fast. The leak tends to drip off the backside of the bottom of the dash, making a puddle right between the brake and gas pedals. Since water likes to travel in odd paths (those of you with roofing experience know this), I cannot easily tell where it is getting in. The passenger side leaks as well in roughly the same area.

I tend to think it is the seal around the windshield, but that just seems too obvious. I will put a hose on it and check, but it would be nice to have some specific areas to check. Any thoughts?

 

The windshield seal would be the first place I'd look. Of course I'm biased as my truck leaks there, well at least until tonight when the windshield comes out.

 

They also leak through the cowl. I removed the firewall insulation and heater assy. to reseal the seam. I replaced the insulation with the ABS type.

 

Have you checked the drip rail area? You might need to clean and scrape old seal material away and re-apply a sealer in the drip rail. just a thought.

Staying low for now
Robert

 

Mine leaks through that welded seam between the windshield and the drip rail, that water then flows down inside the A pillers and drips out under the dash. Water takes some strange paths sometimes.

 

One of my trucks had started life on the coast. It developed a good case of cancer when the salt water sat in the cowl and rusted through at the inside seam. It has been a challenge to fix (still not there yet and may just replace the cab) and led to the rusted out floor pan. My last attempt will be to use POR.

 

I doubt it's the cowl. Check your driver wiper bezel. If its loose or mising the gasket, your likely to find the leak here.

 

Wiper bezel.

 

The reason I said cowl was that when I replaced my windshield, I had pulled out my wiper bezels to replace them with a pair that had better chrome. I resealed the bezels when I put them back in.
When the first rain came, I noticed some water on my cab floor. I called the glass guy and told him that his new windshield rubber wasn't sealing. It was he who told me that it was very common for these trucks to leak at the seam below the cowl.
I took out my heater and firewall insulation, got out the hose, had my buddy spray down the truck while I was inside. Sure enough, the spot-welded seam below the cowl was the culprit. I waited a couple of days for the truck to dry out and scraped the old seam seal out and resealed it with ultra silicone and cured my leak.

 

Great ideas...in hindsight, I wish Ford had used galvanized floor pans like they did on the steps. Obviously, my floor pan on the driver side is shot, too...a piece of scrap sheet aluminum and 30 pop rivits works for now until the refurb.

Thanks, fellas.

 

Speaking of cowls, I bought a rubber cowl seal about a year ago, but have no idea where it goes (can't SEE where a rubber seal like this goes).

Where does it go?

I have the exact same leak as you're describing. The original owner of my "CA" truck pimped it out years ago by installing carpeting all over, even up over the gas tank and sending unit. Years worth of drips soaked into his custom carpet, and didn't reveal itself until I ripped the hideous stuff out and found cancer in the floors of my supposedly rust-free West Coast truck. (See my alternate post "have you ever paid too much...")

 

[QUOTE=brider]Speaking of cowls, I bought a rubber cowl seal about a year ago, but have no idea where it goes (can't SEE where a rubber seal like this goes).

Where does it go?

What you've got is called cowl lacing. It goes under the hood, at the rear of the hood, on those little nail head looking things

 

Okay, so when you close the hood, the rear of the hood seals against it?

What purpose does THAT serve?

 

^ Correct.
I think it supports the rear of the hood.

 

Soooo, theres not supposed to be water in cab when it rains? I just considered it my automatic floormat washer. Seriously though I traced my leak back to the wipers as well.