Firstfives.org

76 530i sitting all winter....clutch pedal goes to the floor...no obvious hose leaks and the resevoir was down but not by much.....I'm assuming either the master or the slave has failed internally....maybe they are even the original units?....I have a new master cylinder that was included with a parts car I once bought years ago....has FAG 59 B7 on side and 15F3. S5340 on the other.....anyone know if this the correct master?...sure looks the same.
I'm going to replace the slave cylinder while I'm in there.

99+% of the time if it fails and doesn't use fluid it's the master, if it uses fluid it's the slave. I don't know on the numbers on the side of it.