About a month ago I replaced the brake light switch. Didn't bleed the brakes. Went riding and the rear brakes worked fine. I pulled the rear wheel and had the tire replaced, reinstalled it and now I have brake problems. I did not open the brake system or remove the caliper durning the tire change. If I pump the pedal I get good brakes. A soon as I move the bike as little as 3 feet I loose braking. I bled the brakes but it didn't help. Anyone have any ideas on this?