I drove my '69 Z28 last nite (non JL8) and at the end of the drive, I noticed the brake pedal feel changed somewhat. The pedal itself started making a groan noise when I pressed it. It might have felt a little "gritty" as well. When I pulled the car in the garage, I noticed that the brake lights were still on when I climbed out of the car. I reached into the car and depressed the brake pedal down, then lifted it up from below with my foot. The brake lites went off. I haven't drive the car again since. Does anyone know what might be going on here. Do I need a new brake light switch, or is it something more serious?