No
yes
is it a new chain? if yes, it should have come with a new master link, if no, you'll be buying a new chain soon enough. Of course it's always a good idea to have a spare in the box.
the chain is not old i just changed the gearin so it is the wrong lenght now i was wonderin if i should get a new master link after i take it apart or if the old one can be reused just fine?
if you need it done now, as long as your carfull, grinding the heads off and poundinh them through w/ a hammer and punch will be just fine, a chain breaker is just for convienance.
and yes, you can reuse the master link as long as it isn't mangled.
Have you got a good vise? Thats what I use, just clamp it in and get a nail or something and drive the pin out of the link you want to remove. I have broken every chain breaker I have ever owned, except for the one that I use on chainsaw chain, which isn't big enough for MC chain.
I have taken apart literally hundreds of chains in the past years, and have never once broken a chain breaker. What you will do is eventually wear the pin out.
Grinder slag and elastomer o-rings do not mix well.