Bad slave cylinder?

[Rangerdanger86]

I have an 86 ranger with the 2.9 I replaced the clutch and slave with ones from napa last yr.it leaked internally right away. Drove the truck for about 2 months. after reading about the junky after market slaves I figured I would avoid the hassle of warranty and put a ford one in. Replaced the master cylinder also at this time. Drove the truck for about 20 miles and its leaking again. Any suggestions on what might be going on? Or how to stop this from happening again?

 

[enginepaul]

Guessing here, but it might be the line from the master to the slave or the connection.
Clean everything; operate clutch several times and then check for leaks.

AND see if there is a way to test the slave before installing it! I put in one from O'Reilly and it was bad. From the illustrations on-line, all of them are the same made in Mexico junk.