Clutch Issue, dead pedal
 

So, I'm cruising home from work and decide to stop for some beer a few nights ago. I shifted from 3rd to 4th, pedal felt a little weak, from 4th to 5th, quite weak. When pulling into the store, pedal almost effortlessly went to the floor without effect. My brake fluid resevoir was a little low, had enough to top it off, but that yielded no difference in clutch feel. I'm sure the clutch itself is fine, as there's been no slippage and i usually drive it easy. I'm wondering if this has happened to anyone else on the site. If so, is this typical for clutch master cylinder or clutch slave cylinder failure? and, what is the best way to test them? I've not begun trouble-shooting yet, wanted to see if anyone had advice before diving into it. This is the first time I've had to troubleshoot a hydraulic clutch system. I have previously had to change clutch cables in a few Nissans, but this is quite different. BTW, car is a 93 gs, on which i did an atx-mtx swap 3 years ago.

ok only question, does the pedal stay on the floor? if yes than bad master if not bad slave
i have a mx3 i put the 2.5in and had the same problem

Pedal returns to its normal position. now, to see if the regular parts stores sell the slave cylinder. Thanks!

Thanks!
Slave Cylinder, it was.
I was surprised by the price, 41.99 + tax at AutoZone. I thought it'd cost more.