You can secure the mounting flange of the
Brake Master Cylinder in a bench vise, remove the master cylinder reservoir cap and diaphragm, install suitable fittings to the master cylinder ports, install transparent hoses to the fittings, fill the master cylinder reservoir to at least the half-way point, depress and release the primary piston, continue to depress and release the primary piston, remove the transparent hoses from the master cylinder reservoir, install the master cylinder reservoir cap and diaphragm, remove the fittings with the transparent hoses and remove the master cylinder from the vise.