Hi Thomas,
Here is a quick answer.
Ferrule click can mean one of two things: (1) The ferrule is loose at the cane, or (2) The ferrule is no longer tight and the metal to metal connection is worn-down from use. In either case, a repair needs to be undertaken by a skilled craftsman - not the neighborhood handyman. If the ferrule is still functional and merely loose where it is glued to the bamboo, it will have to be reset and the ferrule station will perhaps have cause to be modified. Pinned ferrules must be carefully removed and the tiny pin remounted. For malady #2; A worn ferrule should be replaced, although I have known anglers to lightly electroplate with nickel-silver to compensate for the slop. A crude remedy and not at all recommended - some people chuck the female portion in a vise with the slightest touch of pressure to compress. I am sure there are some cane rod makers on board who can handle this question better than I.
Danny
http://www.NorthwestFishingBooks.com