I have 4 wheel disk brakes on my barracuda. Big bolt pattern front, ebay disk rear that uses mid 80's Cadillac Eldorado calipers.
I have all new hard lines along with new hoses and calipers. No leaks but I cannot get a steady firm brake pedal. Pump them and they are good. Let it set and you have to pump them again. The master cylinder was new but old. I did not bench bleed it but have bled the system 4 times now. No air to be seen. Could it be a bad master cylinder? I hate to spend the 200 bucks for a new wilwood one if I don't have to.