Gonna quote from the other leak thread:

I can and will tell you run fast and run far from silicone caulk. There's a right way and wrong way to do it, the seam sealer Ford used lasted this long, why not go back with what came off?

Also upon looking at your pictures of the leak, I'm almost tempted to say it's leaking at the rear window seal and not the body seam. Not there to judge and inspect it so YMMV.

 

Awesome info, thanks. I'll maybe double check things tomorrow and take it from there happy new year

 

For what it's worth, before I knew any better I used clear silly-cone and it did NOT like being painted over one bit! Had to use a wire wheel to get it all out. What a mess.

 

Agreed. But there is no need for urethane on a rubber gasket.

Remove the rear window, seam seal the seams, let dry and reinstall the window

 

It's the bane of body shop existence.
I remember when I first began working in this shop, and the owners had also hired a new mechanic who had never operated in a collision repair facility. Cracked open a tube of RTV and went to sealing something (IIRC it was a '69 Firebird rear end we were rebuilding!) When the painter ran out of the booth to slap it out of his hands and throw it out of the shop. I walked into the booth just in time to watch paint he had just sprayed on half a car literally run off the body like oil on water. Never again did we allow Silicone in the shop!

 

I wasn't talking about the window seal Brad.
I was talking about the rain gutter and the seam running TO the rear window opening.

 

I ran a bead of clear silicon along the bottom of the window and it seems to have cured the leak

 

Hey guys, I know this thread is a couple of years old but thought it would be better to post here. On my 2004 F150 SCrew Larait I'm having the same issue with water under both mats in front in that rail where the wires are and it makes the carpet wet. Back mats are dry. I already repalced the 3rd light. The only time it is wet is when we have a good rain. During the summer I took the carpet up and made sure it was dry then put carpet down and it was dry for a good 3 weeks while I was using the AC (then we had a good rain and it was wet again). So I don't think it is the AC. I did remove the running boards a couple of years ago and it was maybe 9 months later I noticed the wet carpet issue but would not think that is related but maybe it is. I will look at the rubber seals around the doors but would both doors go bad at the same time? That reminds me - the drivers side is worse than the passenger side. So the passenger side will have some dampness and the drivers side will be wet. It's always under the mat.

Thanks for the chime in! If anyone has found "the" solution I would really like to hear it. Great Truck but need to fix this issue.