Fixing fist fighters...
Is it possible to reattach an arm on a fist fighter, and make it work correctly?
It depends on which parts are damaged. Some of the plastic can be glued and some can't.
How About Replaceing The Band Holding the Legs For The Fist Fighters?
This is from the old board and comes from the wisdom of Megotu.
The FF leg connector band is a simple loop. The perfect sized replacement is the Much Maligned White Doc Mego body band. Doubled up with one hip pin through the U of the band and the other hip pin through the 2 O's of the band.
Here are a couple of links from the old board that may be helpful as well.
Often the easy fix is to replace the FF Torso with a new one (you can even install your black slide button if it's one of the UK ones). I've found that with a little search you can usually pick up a FF body inexpensively on evil bay.