A little water will get inside the door from time to time, for instance when you have the window cracked during a rainstorm. The outer weather strip seal, which is against the window glass, should keep most of the water out of the door, it won’t seal perfectly at the ends and as it ages. Plugged drain holes in the doors are one of the major contributing factors in the bottom of the doors rotting out, not the only cause!
Also the window glass run channel in most of the older trucks is pretty much shot, this is another avenue for water to enter the door.
If you think about it, with a good seal at the outer WS and fresh glass run, door handle/lock gaskets, there really isn't any where for the water to get in.
Denny Graham
Sandwich, IL
