If you don't have any broken parts, you don't really need to take them apart. I didn't take my Challenger tracks apart. I just cleaned the old grease out of them, repainted and re-lubed them. On my Dart, I was missing one of the rollers and cages. They were also really rusty and nasty. In order to get the two sections apart, you need to drill out and remove one of the rivets. With that rivet removed, the two sections will come apart. You can replace the rivet with an allen head bolt.
When this question came up the last time, someone posted a link to a good write up on how to do it. Do a search for it. That will help you more then the few pictures that I have.
