One wheel cylinder expands on its own.
All new brake system on my 1965 Chevelle, converted to a power dual master cylinder, has a right rear wheel cylinder which expands on its own, even with the drum off, car on jacks at 40 mph. The push rod to the mastercylinder has been backed off so no constant pressure, no heat on the line as the cylinder expands after 10 minutes, though the line and reservoir fluid is cold. The brakes have been bled numerous times with DOT 3. The same line is in common with the left rear cylinder which functions properly.


