brakes 190e
 

1988 190e 2.3
break pedal gettingweird last few days. started on the highway when decelerating and braking. brake pedal travel kept increasing about additional one inch,soft pedal pressure. brake fluidflushed out and replaced about two months ago.new rear pads. no observable leakage. front pads do need replacing but i've never before encountered this type of problem because of worn pads, but i've never owned a benz before either.vacuum problem? or is it more likely mechanical i.e., master cylinder, pads, hidden leak, caliper, etc. thanx for any advice.