The stock slave cylinder can be rebuilt using a Napa UP-255 cylinder kit. I don't believe the slave on my car is stock, as it's aluminum, anodized blue and has no snap ring keeping the piston in. So I obtained a UP-255 kit from Napa today. This photo shows the KIT part on the LEFT, and my CURRENT slave piston on the RIGHT. The first thing to note is the kit piston has both seals pointing the same way. The piston from my slave has two seals but they point opposite direction. I don't know why.