Steiner Commander Compass not working - possibly low of fluid?

Greetings I have a pair of Steiner 7x50 Military Marine, Commander Pilot binoculars with a compass on top.  The compass moves a little but does not change as one turns around.  I can see a "water line" in the display in the right lens when i tip the binoculars up and down - not sure if this is the problem.
Does anybody know anything about what it takes to open these up and see what is wrong?  Or does anybody know what fluid is inside the compass? It would be nice to have this ready ahead of time i figure.
I also need a set of caps (all 4) if anybody has a idea how to find these or know of suitable replacement caps I would love to hear.
Thanks for any info!