1967-1970 Mopar B-body Charger, Coronet, Roadrunner, GTX & 1967-1974 Mopar A-body, Brake Distribution Valve A/ B-Body Brake distribution valve. This kit includes the valve and mounting bracket. This mounts below the master cylinder on all drum and disc brake cars. B-Body Note: Used with BLK247 & PR104B on Disc Brake Cars A-Body Note: Used with PR104B on Disc Brake Cars This is the valve that was on your Mopar below the master cylinder. The valve meters pressure between the front and rear brakes and if the pressure drops it trips the valve and sends current to the brake light in the dash to let you know something is wrong.