SO, I just bought a Flatline 4.5k that is currently attached to an in-hydro 72/45 PMI tank. The seller says it needs a rebuild though, and included a rebuild kit.

I however have NO idea how to go about rebuilding it... Do i need to remove it from the tank? how would i go about doing that? How similar is the process to the 3k rebuild here: MCB 3k Flatline Rebuild

Any help would be appreciated.