Have you put it back together and bled it yet? You may have had air in the system, although it usually is the opposite symptom (spongy then firm) but it may have just needed bled, also make sure there is no looseness in front wheel bearing, or bent caliper mounts.I was riding the other day and had a bit of a stack. my bike landed on the front calliper pretty hard . there is pressure for about a second before it goes spongy, i took the master cylinder apart. it looked clean and the orings look like new?