Hi. 70 chevelle with drums all arround. Last night luckily near home. I first heard a loud noise, like my front left tire hit a pothole. Then when I applied brakes, the pedal felt like it was moving hard to soft and then a bad noise, boom boom boom,while the pedal was vibrating soft to hard. I got home and am about to go out this am to see what I can find. It feels like something broke inside the driver side drum. PS. I guess by the use of.... boom boom , you realize im no mechanic. thanks for any help..