I have the longer version of this center column for my Feisol 3441T:
The bottom piece, along with that hook, unscrew from the column. The top is fixed. On my last trip, it broke off due to falling over in the wind when I wasn't around. I think combined with my ballhead hitting the ground, it put a lot of pressure and broke it off. It seemed to be attached by some kind of metal. As something to make it still usable, I bought some superglue and reattached it. It seems okay.
This part doesn't seem to be something you can buy on its own and if possible I'd rather avoid shipping it back for replacement/repair just due to cost associated with that.
Is there anything I can do to secure it more? Put a lot more glue around it? I just worry because I want to have full confidence in it, and combined with a ballhead+camera on top of it, I worry about the single point of failure. Would the glue damage the carbon fibre ("melt" it?)
Edit: I should mention - one of my biggest worries is having the column down (most of the time) and hanging my backpack from the weight hook. I'd hate for it to somehow apply enough downward/upward pressure to just pop that top piece off, which means everything risks falling.