What type of brake fluid did you use? Not sure if that's the issue, but I'm fairly certain Ford used ATX fluid rather than a DOT 3 or 4 fluid. Not sure if the two together can give this feeling, but something to consider I guess.

2000 CSVT Silver Frost: #942 of 2150 HID Projectors and Fog Light Mod, Optomized TB, MSDS headers 2003 Silverstone Z