Rodeo Tranny problems

[sentry00]

I have a '96 rodeo, 4cyl. with the Borg Warner 5spd. I had noticed the the tranny was becoming a little more difficult to shift gears, and occassionly it would get stuck in one of the gears, although this was totally dependent on what gear I was in when I was downshifting, so I investigated the situation and found the master cylinder was out of fluid, so refilled it and had my wife assist me in bleeding the system. This seemed to resolve the problem for almost another two weeks when it started again, so I ispected the hydralic system further,this is when I discovered a thin black black fluid had been dripping from the front of the tranny belle. So proceeded to obtain a new slave cylinder and replace the factory cylinder once again had my wife help in bleeding the system and was content that all the air was out of the system. then started the car and attempted to put it in gear only to find that the clutch wouldn't dis-engage. so inspected the hydraulic system furter to find the master cylinder was the initial culprit, it was slowly leaking fluid down the inside of the firewall, so I replaced the mastercylinder, and once again bled the line, only to find the problem still exsist, am quite sure the actual clutch is fine, it was replaced about 9 months ago, due to it not engaging. I have folled the instructions in my Chilton's guide to bleed the system, and follwed these instructions to the letter.
I had noticed that somone else had posted about using a vacumn pump to get all of the air out of the line. If anyone has any suggestions on what could be the cause of the problem please help, or any suggestions on how to bleed the line better, i would really appreciate any help.