...that supposedly "didn't budge", not that of the "pump arm" you were talking about? I think you see the problem now -- if the connection is that indirect, then it's _not "manual" enough_.
And yes, of course I've had that happen, lots of times... With the car standing still and jacked up, while working on the brakes. Never otherwise -- perhaps *because* I took care to do it while standing still and jacked up.