Linhof Levelling Pan / Tilt head users?

I've noticed some looseness on the base where the head rotates around its axis. I have to fasten the lock on the side quite firmly to stabilize the head completely. I recall there was no looseness the last time I've use it. Do any of you notice the same behaviour? Please see the picture attached for what I'm talking about.

http://gallery.leica-users.org/d/401826-1/P1190092.JPG

Thanks.