My shock absorber has gotten so it will not hold pressure, so I ordered a gasket set from Cane Creek. It looked simple enough, but I was unable to unscrew the piston. Cane Creek advertises a spanner wrench for this purpose for $40+, but when I called a very helpful person advised me that they are available at most bike shops at a much cheaper price. My local dealer said he could order one for me for $6, but loaned me one for the shop which I returned the next day. However, I could not loosen the piston even with a suitable wrench.
Cane Creek does have a replacable piston for $50, or you can ship your shock to them and they will overhaul it for $80.
They no longer have available new AD5 shocks for the Bike E, and their current shock - the cloud nine looks similar but I was told it will not fit a Bike E.
I am planning to ship mine for overhaul and will post the results, but wonder if anyone else has had experience replacing gaskets on the AD5
or similar difficulties.