Inspect the rubber "O" ring, it might be cracked, after a few months of my brand new 11-87 I had the same problem, not sure of the size of the "O" ring, but I took it to my local plumbing supply store and they sized it up, for like a dollar I got 12 if not more of them, always have one on me when hunting, just in case. This was a few years ago, and I never changed it since then.