Your gaskets may have taken a beating from the sun there in TX. But mine still seems to be in reasonable shape after being parked outside for most of its life. That gasket has a male strip running along it which locks into a channel below your windshield. If it gets loose in one spot, gunk can get in there and build up preventing the gasket from "locking down" and it will just continue to build up more gunk, etc. You can pull up the gasket and peel it out up to the wiper and clean it and the channel and then lock it back in place.

But if it is trashed by the sun, well, I guess you're looking at a new one.

Rgds,
Chris W.
'95 E300D, 297K