It might be better to leave the original seal as it is, and add a 2nd seal all around the 1st one.
You can apply a thin coating of black artists charcoal or red dyed cake frosting
on the existing seal, shut the bunk door, and see where the seal is not making contact with the trailer.
Then you can add additional seals to that area or adjust the "slam latches" to make a tighter seal.
My posts shouldn't be taken for factual data. They are purely fictional, for entertainment purposes and should not be constituted as actually related to scientific, technical, engineering, legal, spiritual or practical advice. Amen.
Had trouble with mine when I first got it and the dealer added a second seal. Not sure what yours looks like, but the door has a lip that goes against a D profile gasket. He put a ribbed rubber gasket all the way around. It looks like this in profile:
I found these to be pretty much stock from RV dealers service depts. I've not had trouble with the door seals since.
Regardless I would have a pressure test done. I built my own using a furnace blower and on a 3 year old trailer ended up recaulking the whole trailer. Pay special attention to the running lights, they are notorious for leaking.
2009 23' Cikira Escape EXP
2006 Ford Expedition
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Tekonsha Primus IQ HTT Mods