pmontero and dieselguy,

When you seal up the unit, a trick I used last time I filled mine was to cut a piece of plastic so that it just fits inside the diameter of the back cover of the inclinometer. I used a Ruth's Chicken Salad lid; cut it down to approximate size and trim, trim, trimmed. I then RTV'ed the whole thing in so that flimsy little rear cover was total sealed.

It hasn't leaked down yet. <img src="/forums/images/graemlins/smile.gif" alt="" />

Oh, yeah - I used mineral oil as well and injected it with a veteranary syringe, but a turkey baster will work too.