Craneman,
You most likely have the unit sold by Dennis Quella at Pantera Performance Center (Denver). You can get a rebuild kit from Dennis. If you have the earlier version -Generation One - it has a bearing no longer available. You will need to upgrade to Generation Two which has a new piston and bearing (larger bearing I.D.) Your old piston may serve as a core for the newer one if not damaged. It is a McCleod (SP?) product - do a web search. Set up is very critical and measured in thousandths of an inch. They were initially a way around the short throw of the stock slave cylinders. But now with the vendors providing the longer throw (smaller bore) slave, the internal units are probably more trouble than is needed. There is no external adjustment method, you have to have the ZF off, and the bearing is not the stock bearing. Nothing wrong with it, though. The quad seal in the piston is prone to drying out if not used. Depress the clutch every few weeks if you are storing car for any length of time, to keep the seals moist. I will email you, or anyone else if asked, some photos of Gen One and Gen Two.
Larry
