I'm not sure of the exact thickness of the factory flap material,
but I would check a dive or surf shop for some neoprene wetsuit
material.  Thickness varies from 3 to maybe 8 millimeters.

Mike Snow
1982 Westfalia Diesel

> Several posts have suggested using weather-stripping.
> Don't see how this
> would work, since the flaps are actually flat sheets of foam.
>
> I don't have one in my hand, so measurements are
> nowhere near accurate, but
> they are approximately 2.5 x 4 inches (about the size
> of a poker card).  The
> trick is that in cross section, they have a lip, sorta
> like this
> ^------------------^  .  The lip fits around the
> perimeter of the plastic
> flap, or more precisely, flap halves, since two of
> them snap together around
> the spindle, and actually makes the seal.
>
> Thanks,
>
> Karl Wolz