You may want to completely clean the door and frame jambs. From the inside close the door and see if the door and frame have any large gaps. Vintage Trailer Gaskets have a library of various Airstream gaskets. We’ve used D-gaskets successfully on both our trailers. Also, we used 3-D gasket adhesive when applying. If the VTG site is confusing, I have called them and spoke to the owner for help. He is very knowledgeable. Good luck
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