Nissan used tape with butyl rubber to join together a seam that runs along the rear wheel arch instead of welding it. This rubber over the years deteriorates and creates a path for the water to get inside the car. I bought some butyl rubber at Lowes and replaced the OEM piece bigger,better,stronger(orange box). Before, my passenger rear floor would be soacked, and the back seat would be dry. Underneath the seat would be wet. After the replacement, the vert is dry.

Good luck!

Good info, are you on northwestnissans?

I used to be, i since then have moved to Houston.

I would also recommend that we all take off the the seal around the windshield, where the top latches to the frame, sand off all the rust, use some rust neutralizer, rustolium paint it all, and then reassemble it all using butyl rubber in as many crevises and edges as possible to keep the water out. In the end its going to be worth it.