Copied from an earlier thread about changing the oil, see the complete post at:
http://www.mini2.com/forum/newreply....y&postid=90365
This is a little difficult to explain but is very clear once you do it. The ends of the filter element are heavy paper, and the holes in each end are undersized for a tight seal. You need to press fit the new element into place first to enlarge the holes, or you'll have trouble lining up the can and filter and engaging the treads on the block. Use the palm of your hand to press fit the filter over the tube inside the can first, remove it, wet the seal on the other end then press the element into place over the tube on the engine and leave it there. Now you can screw the can back onto the block easily (don't forget to replace the o-ring on the can.) By the way, there's no mistaking which end of the filter element goes where, the larger hole in the can, the smaller one on the block.