Thanks to everyone for their help. The master cylinder is empty so tomorrow I'll be looking at the operating cylinder (slave cylinder). The master cylinder was replaced t some point (previous owner left all the replaced parts with car). Thanks again.
72 240Z all original. clutch pedal failed (pushes down easily) does not allow shifting in gears. Transmission will engage in all gears when car is off and no clutching. Is this likely a cable loose? If so, can a novice mechanic repair it? Thanks