Master Cylinder: 79-80 4x4 Disc (Brand New)This cast iron master cylinder is designed for front and rear disc brakes on 1979 and 1980 Firebird models, including the 1980 TA Turbo. It is also suitable for second generation F body vehicles equipped with retrofitted rear disc brake systems from those years, ensuring the proper fit and reliable performance. If your vehicle has been retrofitted with rear disc brakes, note that the proportioning valve differs from the one used with rear drum brakes