While there are plenty of AD series (AD 4, 5, 8, 10 & 12) and Cloud Nine shocks still in use, we no longer manufacture small parts for those outside of seal kits and valve kits. Therefore, we can no longer offer a Factory Service option for these shocks.
Many times, an AD or Cloud Nine shock that is not holding air simply needs new seals and/or valve. AD 4 & 8 shocks are not serviceable. We do offer kits for AD 5 and Cloud Nine directly on our Rear Suspension Parts & Accessories page under the "General" tab. Additionally, your local bicycle dealer that is versed in suspension can get kits and perform the service.
AD 10/12 kits are no longer available from Cane Creek, though a majority of the seals for the AD 10/12 can be found in the AD 5 kit. All seals are standard sizes and individual replacements can be found commercially.
Manuals for the AD 5, AD 10/12 and Cloud Nine can be found at the bottom of our Manuals & Support Documents page under "Legacy Shocks."
If replacing the seals and/or valve does not solve air leaks, then it will be time for a new shock. To help you determine what you would need, please refer to our Everything You Need To Know About Rear Shocks article.