Originally Posted by phidauex
1. What sort of bike is it?
It's an X-Mart bike. I can tell because he said "Promax" and "brake" in the same sentence.
Now Shredder, before you do anything, and especially before you spend any money on parts, do what phidauex said and get a book on bicycle mechanics and read through Park Tool's repair guide website, and read both thoroughly, again and again. Only then will you know exactly what parts you need and what you need to do. And then you might be in trouble because your bike has a one-piece, or even worse, a thread-in crank and you can't find a replacement. If you don't want to spend the time, then take your bikes to the bike shop, the repair bill will probably be reasonable.