Brake booster vacuum leak
I had to remove power brake booster and master cylinder on 76 K 5 Blazer, to cut and rebuild brake pedal to go around new ign. switch and other things on tilt wheel etc: After finding pedal now hit floorboard before brakes worked I cut pedal and fixed that problem. Brakes seem to work fine now but when I have no pressure on the brake pedal I hear what sounds like a vacuum leak from inside firewall around brake booster. If I just lightly touch the pedal the noise goes away. I havn't put the brake light switch back under there. Would mounting that so there's a lil pressure on the pedal be the answer? Don't see any leaks around vacuum line on front of booster. Disc on front drums on back. First time on forum and beginner hot rodder.im 60'years old and was into in the 60s but forgot most of it now.