I have a Mares Cyrano 1100 with a intermittent leak in the muzzle. Air escapes only when the butt of the spear shaft is seated in the piston and the wiggled around. Also when i pull the spear out of the muzzle, a little bit of pressure escapes. After reading the exhaustive information on disassembly i am ready to attemp a repair. However i don't know what exactly i should replace. The piston? All the o-rings? the shock absorber? I dont really want to take it apart any more that i have to. Has anyone ever had this issue? What is most likely the problem?