Brake Parts (BPI) is recalling certain Hydro-Max brake master cylinders branded as Raybestos p/n MC390565, NAPA p/n 390565, Carquest p/n E151557, and GM AC Delco p/n 18M870. These cylinders contain a 2.0 inch bore and 84 cubic inch reservoir equipped with a brake fluid level indicator switch and without a differential pressure switch, manufactured between July 1, 2011 and April 12, 2012. The brake fluid level indicator (FLI) may not properly detect a low brake fluid level situation and warn the driver.