Well, I never knew there was a sleeve in there. Is that Marzo or Ceriani? Maybe they both have them. I'll have a look next time I have one apart. It's not shown as a separate part in the Marzocchi manual, so it seems the factory jammed it in there never to come out again.
It looks like the fork sliders are made as a tube open at both ends, then a plug is fitted into the bottom end. That certainly answers a bunch of "how the fuck did they machine the inside of the slider" questions that are often in my mind when I disassemble forks! I guess it would have to be quite a tight interference fit to be oil-tight (unless there's an o-ring in there). If it's just an interference fit, then I assume they heated the leg in the factory to get it in there, then machined the axle/bolt holes afterwards.
I'd suggest you don't do any more hammering. You could be spreading the top of the plug and jamming it tighter. Take Keith's advice and find a friendly engineering shop that has a press. Use a spacer to protect the the inside end of the troublesome plug (like a suitably sized penny washer). Using a press is more controllable and less likely than a hammer to damage anything. It'll move if you push it hard enough. Cracking the joint as you have, may have compromised the oil tightness. Once you have it back in place, it might be worth putting a bit of Loctite After Lock around the accessble end of the mating surface to re-seal it.
If it's shifted far enough to block the oil drain hole, then leaving it where it is and adjusting the axle hole is a less than optimal solution.
Good luck. Let us know how it turns out.
Cheers,
Cam
