Those master cylinders are of specific dimensions, variable length and probably mass as well. I wonder if one could analyze the audio frequency spectrum, and/or mechanical impulse response, to deduce the length of the master and work out the bitting.
The fun part of audio is that there's multiple ways to do it. You can use spectrum analysis, impulse response, harmonic frequency, beamforming, triangulation and more. Some would be easier than others in this situation, but you could technically use any of them to pick this lock.
