Drum to Disc MC Issues

Look in the bore of the new master cylinder. There should be a groove for the little rubber retainer to lock into. Bench bleed the master cylinder. They sell kits cheap at the auto parts store. Mount the master, line up the push rod, and just step on the pedal to lock the rod into the bore. You don't need the dust boot. And the larger volume of the disc master is needed. It's not just for looks.