Hy oldcarandtrucknut, I think your master cylinder may be bypassing internaly. Synthetic brake fluid was designed for two purposes, raising the boiling point of the fluid, and it is not hydroscopic, it doesn't draw moisure out of the air as the alcohol based fluid will, consequently it makes it very apppropriate for vehicles that are not driven daily. If you have the equipment you could put a pressure gauge in the front system and see if you can generate any pressure in it, hope that helps
