Hello,
The system is complicated, it requires precise and regular servicing. Otherwise becomes problematic.
Bleeding the system is one of the steps of this servicing. As far as I remember, there are a couple of threads on that. Check this one, should be helpful:
Any information on changing the clutch fluid on a Fiat ducato 3.0 maxi multijet 2009 it’s the comfortmatic robotic clutch Can this be done by syringing out the reservoir then cracking the bleed valve then auto pressure bleeding
www.fiatforum.com
There are as far as I remember 3 different fluids in the system. One of them, same as the brake fluid, DOT4, is highly higroscopic and should be changed every 2 to max 4 years to maintain its properties.