get some hpi white bladders, fill the shock body with oil, after all the air bubbles are gone, gently place the bladder on the top of the shock body,and gently push the bladder flat onto the shock body(letting oil oooze out), screw on the cap and you're done. another helpfull place is rc411.com, xtreme rc cars magazine, they have an article in the how to section of their site, I believe it's called "build shocks like a pro" check it out, it helped me a lot.