I was backing out my 1930 Ford and all of a sudden, it stopped like I was hitting something. I got out to look and nothing stopping the car. Two things prior to this happening; I rebuilt both rear brakes and after having it out for the first time since the brake repair (The car seemed to run fine then). As I was pulling into the garage, I started moving forward when I realized I still had the parking brake engaged, I released it and pulled it in. Then the next day when I was backing it out is when I experienced the sudden stopping after moving about 5-6 feet backwards. Any suggestions?