See what has happened? The depth of fluid (or "piston travel") in the glasses representing the rear wheel cylinders is only 1/12th of original depth of fluid in the "master." The fluid depth or "piston travel" in the "front cylinders" is 1/24th of that in the "master." The more the wheel cylinder diameters exceed that of the master cylinder, the less the piston travel. The front wheel piston travel is the least, because its diameter is greatest. This is just as it should be, for with disc brakes...