Note to all: I went through the B-pillar thing a few years ago.

I was getting ready to install a stereo in the beast, and was crawling around in the back pulling the side panels off. Everything was cool until I reached under the carpet - of course it was soaked.

First, I checked for the tell-tale b-pillar leak. But it's dry as a bone from the carpet up. In fact, the carpeting itself is dry from stem to stern. It's the pad/insulation that is wet.

I proceeded to remove all of the interior panels from the doors back, then I pulled the carpet up to the rear seat mounts. The water is all on the driver's side on the cargo floor. There's some condensation-looking moisture forward of the rear seat and near the driver's side of the tailgate, but very little. I haven't managed to pull the seat mounts yet (soaking in PB Blaster today), but the water is definitely concentrated in the area in front of the inner fenderwell and driver's side rear seat bracket. In fact, there are puddles at the front. But the truck is bone dry outboard of the body seam at the edge of the cargo floor.

Anyone ever had a leak at the rear seat mount? I looked underneath the truck, and it was really tough to tell much because mine was undercoated by the original owner.

Any thoughts?

 

Have you checked the door seals? I had a large crack in the floor pan under the driver's-side seat, under the rear outboard bolt location. The front inboard bolt mount had broken (it's very weak), and the strain caused the floorpan to crack. I would think it's harder for moisture to get in from the floor, so I would suspect the door seals or even the window weatherstripping.

 

What is the year make and model of your vehicle?

Have you determined where the leak is from?

 

In the old days all that good stuff was in the signature, but I guess you have to pay for that now, eh?

1993 Bronco XLT, 351W, E4OD, tow pkg, manual txfr case

I haven't been able to determine where the leak is. Which is my problem. Can't fix it if I can't find it.

I know the common problems are the seals around the top, or the doors or the tailgate/window, but it's all dry from the carpet up. I can't see any sign of leakage outside of (or above) the cargo floor welds, and there's lots of dust on the b-pillars, inner quarters and under all the trim around the top so I think if it was leaking from above there would have to be some streaks in the dust.

As for a cracked floor pan, under the front seat is totally dry. There's just a few dew drops under the carpet the 1st 3 inches forward of the back seat on the driver's side, but it's nothing compared to the little puddles up on the cargo floor underneath the driver's side of the back seat.

 

You're right in that if it was say the side window seals on the hardtop, you would see a trail down the inside of the quarter panel If the carpet or padding is dry in front of the front seats, that should rule out the heater core or windshield seal. The rear bench seat has a mounting bracket on both sides that go through the floor. It's easy enough to fold up the seat and pull the carpet up there to look for cracks or daylight from below. If you do find the leak there, some silicone should seal it up unless it's a large gap where a body seam is. I ended up making a bracket to fit over the floor crack after I welded it shut, then bolting and welding the bracket. The crack was about 10" long.