Mine is a Mk1, don't know if the Mk2/3/AR ones are the same, or if it is rebuildable?
Mine does this
I bounced up Simms and wallowed up Tipley today and it makes me slightly sea sick, and the back wheel wanders as it unweights itself while the back end wanders up and down after bumps.
Turns out the shock had merely disassembled itself, and the damping appears fine. The sleeve has broken but I should be able to get one good shock by using the undamaged parts from my spare which does have no damping. An awful lot cheaper than reconditioning. Result!
Thanks Dave, but I think the CR 250 shock may be a tad stiff for my style of riding.
John Tremlett of Asburton only charged me £24 to make one good shock out of the two. Result!
Off out now to test it over the drainage channels (jumps) on Johnny Cann's Walk