Hear a loud squeaking noise when stepping on the break what could that be?

-I have a 99 chevy tahoe and was recently in a car accident and had to have the front fender on the drivers side replaced. The accident happened at the beginning of may and it has just recently over the last month been making a loud squeaking noise when having to come to a stop quickly. My dad looked at the front break pads to see if that was the problem and it wasn't. When he toke the wheels off we discovered that the front passengers side cv joint had been leaking grease my dad thought that was what was causing the squeaking noise. Well we replaced the cv joint tonight and toke it for a test drive after wards at first it wasn't making the noise then the noise started again and it sounded it like it was coming from the drivers side. Does anyone know what could be causing this squeaking sound?