Johan,

The clunk is an interesting piece. I'm not doubting your experience with them but just commenting since you did ask. Personally, I've never needed such a device, not even in my aerobats which I do throw around mercilessly. I've had similar problems such as yours when there was a hole in my lines, the stopper was not on tight and one time when the stopper had expanded and leaking through the holes.

Thanks for the info.