The later models of Savage/Stevens/Springfield pumps aren't too user friendly as far as DIY gunsmithing is concerned. If you want it fixed, I'd suggest taking it to a 'smith who knows those pumps.
If you can't resist getting into it, remember to take the buttstock off before you do anything else. On these designs as a rule, the trigger plate assembly is held in place in the receiver by a cross screw and a pin. There is an extension molded onto the (usually cast aluminum) trigger plate housing that the stock bolt screws into, and with the buttstock bearing against the back of the receiver, a good deal of tension is placed on the housing, which in turn draws it tight against the screw and pin. See Part #1 and Part #48 in the exploded drawing at
http://www.urban-armory.com/diagrams/savage67.htm to perhaps get a better idea of what I'm talking about, and why it's a better idea to remove the tension on those parts if you need to get into the receiver.
With a top tang safety on an extension from the receiver, it might not be necessary to do much more than remove the buttstock to get an idea of what needs attention, I don't know. I don't mess with this series because I am not a gunsmith and they are generally a pain to deal with.
If you don't want to spend the money on fixing it, or risk wrecking it, retrain your shooting hand thumb to hold the safety tab forward when actually shooting the gun. And if the safety is that unreliable and you don't get it fixed, I'd also strongly suggest always always always keeping the chamber empty when not actually in the act of shooting it. And make sure it never falls into the hands of someone who doesn't know the gun is more dangerous than most...
fwiw,
lpl
