why are my breaks hard randomly at slower speed with a weird noise? on 1995 Ford Ranger

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
sometimes 1-5 times in a row then it will break fine for a whole day
I have 4x4 abs does this matter?
(2) Answers
Sounds like problem with brake booster. Maybe first replace check valve on it and look for any vacuum leaks to it.