recently getting into fifth gear would grind, so I asumed the synchros were going out. until yesterday when my clutch pedal went to the floor and stayed there! I'm assuminf its the master/slave cylinders, but am not sure.
could it be that problem or something worse? and would the fifth gear grinding be caused by the cylinders?

 

pedal going to the floor and staying there is a leak in the clutch hydraulics. check the boot of the slave on top of the trans to see if there is fluid leaking. also check at the base of the master clutch cyl AND check on the inside of the car, right above the pedal where the clutch cyl goes through the firewwall. look for fluid there on the inside of the car. check the line for leaks, check the level of the resivour. lastly, try bleeding the system to rid any air. worse comes to worse, VICTOIA BRITISH has both cyl's for like 10-20 and 20-30$ dont remember price