It is not always the tbar seals that leak.

When you open the door you should see a dirty line around the door shuts in the hinge area where the road grime does not get passed the door seals.

If you don't have that dirty line and its not something you have washed off then water can get passed that door seal.

In the footwell there are 2 vertical strips of plastic trip

that overlap a little bit.

If one of them has dropped as the glue has failed over the years then it can also channel the water into the footwell that has got passed the door seal.

With cars this old, all the rubber seals need to be treated with rubber rejuvenator/restorer from time to time otherwise it will shrink/harden and let water in.
