I have completely drained and cleaned my front brake line, caliper and MC and now wonder what the trick is to refill the entire line with brake fluid? After I put all the pieces back together, I filled the MC with fluid, squeezed the brake handle and nothing seems to happen. I have bled the brakes before without issue, but this is the first time I took the entire system apart, drained it and cleaned it all up.
Take the bleeder screw out and put your thumb over it. Have someone keep pulling back the brake lever and the air inside will push your thumb free and let it reseat itself. Do till it starts squirting brake fluid.