Cap the MC with a pair of brass inverted flare male plugs (fittings) from the Edelman cabinet at your parts house. If the MC is good & bled out it will be rock hard with virtualy no travel (try light and try hard pressure). then hookup ONE line & see if it still good. if so the air is in the other line. If not good then remove that line from the MC & cap that MC port back up & & hookup the other line & see if it is good or not & if not then both have air & start on that line (half) bleeding it out & as said dont let air come back in thru the bleeder screw threads on the return stroke (make sure your helper has em snug befor he hollers for you to let up on the pedal). You might agitate the fluid when doing the front discs by pumping the pedal rapidly several times then he opens a bleeder on the 4th downstroker (good verbal timing needed). then work on the other half. Put a block of wood etc under the pedal so you dont go past the normal travel range. If the MC is high and tight then the problem has to be at the corners & calipers act up way more than rear wheel cyls. holler how it progresses