This master cylinder is used when converting to a dual master cylinder. This popular conversion makes your old truck safer to drive and gives you the option of non-power when converting to disc brakes. 1947-1959 trucks require the use of a dual master cylinder conversion bracket (Part # DMC5954 or DMC5959)). For disc brake applications a Proportioning Valve (Part # PVK4759DISCDRUM) is required.
