The Liberty Bell was a piece of crap from Day 1. From the time it was test run in 1752 it’s had problems from it’s shitty craftmanship. IT has to be recast twice because the metal was too weak and brittle. But as far as the giant ass crack in it, it was well after 1776 that the crack appeared. Even the name has nothing to do with 4th of July. It wasn’t until the 1830’s when an abolitionist group used it for their symbol and called it the Liberty Bell. But as far as the crack goes. No one is really 100% sure because it wasn’t during some specials monumental moment. Also it didn’t happen all at once. It happened over time at some point between 1835 and 1846.