My 60 cx has survived many bad rainstorms over the past 4 years without getting any water in it. I don't think the screen has even fogged up.
It is pretty easy to take the unit apart. There about 6 small screws. The water seal seems to be a thin gasket that goes between the two case parts. If it were me I would smear some silicone grease on that gasket and put the cases back together and make sure the screws were tight.