Brakes are feeling odd...

[Hocrest]

So on my trip over the weekend, the brake pedal was responding oddly.

After long stretches of no brake use on the highway, when I press the pedal it is firm for about the first bit of pedal travel, then it drops 1" like there is a massive leak, then it firms up again. At that point it will hold pressure, and if I go off the pedal and reapply, it is firm the whole time. But then if I go another 15 minutes or so before I get on the pedal again, it will act up.

I'm guessing at master? does that sound right??