I had the same problem, it looked like the slave cylinder, but it was actually the little fitting on the hard line. I replaced the hardline, and no problems since.
93 Tsi AWD-SAFC I, Apexi N1 turbo back, MBC, K&N w/ hacked can,Walbro 255, Accel wires, 650cc injectors, stage 3 dsmchip97 Neon ACR-Stock