i had to drain the brake fluid from the bleeder niplle at the calipper in order to push back the pistons so that i could install new pads, but it turns out i drained to much and air got in to the system, so i filled up the litle resivoar at the master cylinder with some dot 5,1 but nothing happens, i pump the brakes and tiny air bubbles come out of the resivoar but the pressure does not build, i tried bleeding the system but no air comes out of the nipple just a litlle fluid and still no pressuere, does anyone know what i can do about this? it worked just fine before, only change i did was re route the line to the front of the number plate becuse the previous owner had it behind the plate