I am in the process of rebuilding the rear shock on my 1983 YZ250. Everything on the inside looks good except for the seal head assebly at the end of the shock. Replacing the o-ring around the outside is no problem, but how do I replace the two shaft seals on the inside I.D. of the seal head? The top side of the seal head unit rotates, so I would think that it comes apart somehow. Can somone let me know how to take it apart and replace the inside seals? Would I be better off to buy a new seal head unit? Thanks.