Hy buggy5872, I haven't been ignoring your question, but I haven't had a lot of luck confirming/locating parts for the "56 F370 series". I believe the master cylinder o.e.m. p/n was 2265213 which was Wagner p/n FE-13066. However I can't locate that master cylinder at any of the suppliers. There are different front and rear wheel cylinders listed depending on what front axle is in the truck, and whether the truck had HydroVac, or AirPac brakes. if you could give us a casting number off of the master cylinder, and let us know if your front wheels have a single front wheel cylinder or two wheel cylinders per front wheel that may help to identify what you need to purchase, hope that helps.
