The cork gaskets under the wiper blade pivots on the outside of the car are notorius for shrinking over time and then allowing water to free flow to the floor boards from that point.  I had the windshield out twice on my ’55 Customline looking for the leak before realizing it was coming from the windshield wiper arm pivots.  RTV in place of the cork gaskets resolved that problem.

Lorena, Texas (South of Waco)

You can add it now. You need to get a tip to put on the adhesive so it will fit under the seal and applys sealant. Most likely the leak is between the car and the seal most of the time in the corners. The tips are usually available where the adhesive is sold. Fairly simple fix.

55Birdman  Hickory NC

I'm getting a leak under the dash and it appears to be the windshield seal. When I had it installed no sealer was used....is this the correct way to do it or should they have used the 3M sealer and if so, can I add it now. Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin