lately i have been having issues with my brakes. it only does this sometimes and sometimes it works normal. seems like the calipers of all 4 sides are not letting go completely. i jacked up the car when it did this and all 4 sides are pretty evenly pressuered, calipers are solid and mounted properly and pads are wearing evenly. I havve all new calipers pads and rotors recently put on bout 2 months ago. i thought it might have been the vent on the cap of the matster cylinder but it wasint. now i think it might be the master ciclinder. .. but still not sure i never had a problem like this before. anyone have any ideas?