Hello all,
I have a 77 Impala 2 door, and it was out in the rain a few days ago, gosh darn carpet was wet on the passenger side, mainly in the back. I need to deal with this problem as this car has to sit outside alot.
Heres what I can tell you. The windshield has a groupe of cracks in the lower passenger side. Could water get through cracks? I don't see any evidence inside at all. Being a boiler maker by trade, I know how water can travle. All weatherstripping looks good to almost new. Is there some thing I can do to find the leak? Any help would be appreciated greatly, Gene

The windshield and back glass on these cars it attached to the opening with a sealer that dries out after many years and leaks. Also causes the body area to rust through where the glass and metal meet.
Another common sorce of leakage is around the heater/AC housing where it fastens to the firewall(under the hood). The water leaks in and finds it way to the rear floor area on the passengers side. The housing can be loosened (not necessary to remove completely) and resealed.

Have someone sit inside and watch for water entering. Have another person with a water hose run water around areas the might leak. I suspect it is a leak from a hole in the trough below the wipers. It is a common place for a rust hole. Leavea and other stuff gets in there and holds moisture causing the rust through.