I cannot get my brakes to bleed out. I have replaced the lines, master cylinder, wheel cylinders, proportioning valve, and calipers. I also re-painted my brake booster assembly and in the process may have mixed up some parts from my 1979 2WD F-150 parts truck. I'm wondering if the plunger in this assembly that pushed against the master cylinder may have something to do with my problem. Does anyone know if these plungers could be interchangeable? Also, I see it is adjustable, does anyone have the correct length that it should be for a 1977 F-150 4x4? This is getting very frustrating! Hopefully my pictures upload.