Not completely sure here as i cannot see it but i would hazard a guess and say that the master cylinder needs changing ,but check the fluid level first and if low again then you have a fluid leak but where ?? could be a caliper seal or the master cylinder leaking out of the rear seal and its being sucked into the air intake via the servo vacumn pipe?? could even be a flexible pipe split or a damaged brake pipe ,Evan if pads on metal you should still have a hard pedal ,Have a good look around to see if its leaking first

30k is reccomended brake replacement. If it goes to far it will cost big money