Has anyone replaced theirs yet? Mine is empty. I bought a new one, with no instuctions. Thanks in advance.

I don't have your head. But I recently replaced the bubble level on my Vinten Vision 3 head. It took a long time. The trick is you have to make sure your head is tilted exactly 90 degrees. I did this by placing the head on a flat table then putting a 3 foot straight edge on top and measuring each sides distance to the table and adjusting until they were exactly the same. Once I did that I used a rotating laser level set on top of the tripod head to adjust the legs until I got it exactly level. Once I had that I epoxyed the bubble level in there. It took me about 4 hours to do everything.