Slave Cylinder Issue

I had 2 slave failures, the second time I also changed the Master that seemed to solve the issue...

00 X 5speed 160K

I don't have any advice for you but after I replaced my master I decided to replace the slave at the same time. It failed within a few months and left me stranded. Replaced it again and so far it's held but it makes me think the aftermarket parts aren't well made.

So a mechanic buddy of mine says that if I have an oil leak it could be affecting my slave cylinder. He says the oil could get into the boot of the slave and ware out the seals. when I checked my Slave is always covered in oil. I'm guessing the oil is the reason I've been chowing through these slaves. Since then I've found an oil leak on my valve cover gaskets both sides. They were leaking pretty badly. I've gotten those fixed and will be replacing the slave one more. The transmission belly is covered in oil. I hope it was coming form the valve covers or do you think it could coming from somewhere else also?

What would be an indication that the master cylinder needs replacing also? How do I know its gone bad?

What fluid are you using? Go with synthetic DOT 4 only. The DOT 3 shit heats up and fails. I had this same problem and thought it was a bad master or slave over and over... turns out I was just using shit fluid. I wasted a lot of time replacing parts when it was the fluid all along. This became especially pronounced on mine after installing headers/CEL eliminators that are hot metal which is even closer to the clutch line.

Also be sure to buy good parts. If you got it at Auto Zone I wouldn't rule out that it's just a junk part. I recommend Japanese made parts only. Rock Auto has a good, inexpensive selection.