Alright, So almost a year ago I changed mr pads and rotors all around. My brakes seemed good. 2 months ago they felt strange in the front. So last week I pulled the fronts off and they looked brand new. I slapped them back in and my brakes felt good again. I drove the whole week and I on the highway and I step on the brakes and the peddle goes half way to the floor, but the brakes still catch. Turns out, on the highway I have to pump the brakes before getting pressure. In the city, I'm all good. I'm not losing fluid and we checked the the booster, it's holding vacuum. I'm told I should blled the brakes, but I have not opened up the system. Please help.

 

Bleed the lines and make sure there's no air in the lines

 

If you bleed them and it's still doing the same it could be worn pads oryour master cylinder on it's last leg!