Brake pedal problem.

[Baldrick]

I'm hoping some one can help or put my mind at ease, recently my brake pedal has been going hard, and by that i mean hardly any movement/travel and the braking doesn't seem as good as it should, also in the past it's gone the other way where the pedal has nearly gone to the floor but then it goes back to operating normally.
Any ideas on what i should be looking at as it doesn't seem right to me.

[budweiser]

make sure the hose that is connected to the big round thing (i forgot the name of it) behind the brake master cylinder is not perished

[Tankerman]

Brake pedal!

Servo!

[axelgs1]

I had this problem to. Siezed piston in caliper. Would go hard and softer the more I braked. New caliper and bled system and now works fine.