In this order, caliper in a coffee can and pump it out with the M/C. if there are twin pistons, use a c clamp on the slower one. air won't work at this point so grease gun next.
78 GL 1000, 70 CB750 sandcast, 70 CB836 hot rod, 1124cc 750 dragbike resto project.
You don't need a weatherman to know which way the wind blows.