If the carbon seal is leaking. You can usually crank it up in the water and water will spray from where the carbon seal mates with the stainless hat collar. The accordion boot becomes stiff with age and no longer presses the carbon seal against the hat collar with enough pressure. Many have used a zip as a spacer for a temporary fix. I have been running mine with a zip tie for 3 years now,lol. Also, from the picture, it does appear to have a gap one the top side of the photo.