when a master starts to go away ( bypassing fluid ) usually what happens is the travel of the slave cylinder becomes liminated -meaning it ( the slave ) does not extend as far as it should, this causes the clutch to act as if you put a block under the clutch pedel and limit the throw --

if you unbolt and with out removing the lines, slide out the clutch master, look behind it you may notice it seems wet even tho your resv is full < bypassing fluid - not every time but most of the time you will find this ( a small fluid loss )

if a slave goes bad it normally will leak fluid out ( 99% of the time ) of the boot causing the same problem but with fluid loss

change them both - fresh fluid in an old slave most times will start leaking soon after a master replacement - jz