SB105 flood (again)

Just had my Nikonos SB105 flood twice in 2 days!
After the first one I cleaned it all out and replaced the o-ring round
the end plug. everything but was neat and tidy - but took it in today
and when I got back home the battery compartment was full of water.
(again)
Just trashed 20 bucks of NiMH batteries :(
So has anyone had experince of these flooding? I cant see anything
wrong.....but thee must be something.
There seems to be some sort of 'pressure releif valve' in the end
cap....does this get stuck?
It's under some sort of spring and cloth arrangement - anyone know
anything about it? - dont want to pull it apart and break it before I
know whats under there......

Help....
Al.