Originally Posted by
qclabrat
Edit to above looks like its an air spring design...
Some Head Shoks were air and oil, some coil and oil, some coil and rubber.
If you look at the spec for this bike in 1997 (the CAAD3 year) it was MC60 which had a coil around a rubber part that provided a progressive spring rate, and a sliding nylon damper. Not as good to ride but nothing to leak. After 20 years I expect it's all worn out except the coil, but at the same time wearing out does not render it dead.
Researching this stuff is a nostalgic rabbit hole. More than anyone should care to know at this late date:
https://www.sheldonbrown.com/cannond..._manual_en.pdf