Its been a long time since I've been on this site, just remembered it actually and here I am. still have the same truck, 1999 2.5 long bed. rebuilt the engine in it over the winter, and she's almost back on the road, no more ticky lifters and oil leaks. it was sitting outside waiting for the engine to get done and during that time it started to leak water, bad. I opened the door and there was a puddle of water an inch deep on the drivers floor, so when the engine was put back in I ripped out the interior and found the rear window / cab straps / 3rd brake light was leaking. sealed them up. But I also noticed a rust hole in the a pillar by your left foot if you were sitting in it, did a leak test and water was coming in from the far corner above the ebrake pedal (there's a crack in the sealant that it was coming through). and there is a hole in very bottom left corner of the floor pan. long story short my floor is rotted out so I'm gonna weld in new metal. my question is does anybody have any idea where this water could be coming in at? I think I have an idea but I want some second opinions. thanks in advance.


im gonna have to replace the door seal metal on the bottom too.

here's the rust hole I cut it out a bit so I can reach my hand up in there. the little hole where I suspected the water is coming in is is the corner.

there's also the crack above the ebrake but I couldn't get a pic of that.

 

Well the cowl does have a drain on each side that can get clogged up with debris
Should be a drain hole on each side just in front of the door

Other possibility would be the windshield trough, pull out the molding and have a look at the lower corners, water sits there all the time so if paint is gone it will rust thru
You need to pull windshield to repair these leaks

You could use a garden hose to put water in the cowl to see if water is getting in from there
Then cover the cowl. so no water can get in and put water around windshield on that side to see if that's the leak

 

Thanks for the reply ron. I have the fender pulled right now. The cowl drains are nice and clean. And the cowl insides are squeaky clean. The bottom corner of the windshield does have some rust so it's a possibility it's that. I had a glass company check the windshield. They said it was good but I'm not so sure.

Heres the bottom corner of the windshield

Here's the crack in the sealer above the ebrake

 

Well the windshield is sealed to a ridge, so no metal can touch the edge or it would shatter, has to be a gap all the way around it
The trough or valley runs around that ridge, so windshield can be air tight and water sealed, but trough can still be rusted out

 

hope its not that if it still leaks next summer I'm gonna do the ol' 2x4 trick on the glass and get one put in and see what's behind there.

 

Did you find where the water was coming in. My 98 is doing the same thing and floor is rusted like yours. They don't make a new floor pan for a 98 so I ordered one for a 92 which looks similar.