based on pic in the other thread the bike is lower end diamondback, with square taper bottom bracket. It is would be amazing if it was anything other than standard 9/16 size pedals.
OP needs to
- replace cranks or
- get helicoil job done
- find a bike mechanics class to to take or watch in detail how to videos before touching another thing on the bike
- find a way to work with bike not upside down, can just hang from a pair of ropes. this will make all things easier
__________________
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)