headshok stange noise

I have a cannondale Jekyll(model 2002) and it is a long time I hear
cracking noises from the fork(headshok super fatty dl) when I apply the
brakes (specially on hard braking) and when I am steering,but I cannot
find the source of the problem.Does anybody have any ideas what the
problem could be and how can I fix it?(headset bearings,cartridge)?Has
anyone experienced the same problem before?

thank you