What's the purpose of this "oil seal"?

[Captkirk]

In replacing the stator on my '84 1200 Standard I'm doing maintenance on several items while the engine is out. The clutch slave cylinder assembly has an internal "piston seal" to keep the brake fluid inside the cylinder but what is the purpose of the "oil seal" located on the outside end of the piston? The clutch push rod (or "lifter rod") fits in this indentation in the end of the piston. Why is the "oil seal" needed? Do I need to replace it also? The manual says to lub the end of the push rod before re-assembling. Do I put grease in the indentation and the "oil seal" keeps it in there?

Anyone know for sure?

Captkirk

[cooter]

G'day captkirk, yes the seal should be replaced if it has been disturbed, shows any sign of leakage or is in less than perfect condition. It prevents engine oil from finding its way to the clutch side of the slave cylinder piston. If oil was present on that side it would get around the slave cylinder piston and piston seal. That seal is for sealing brake fluid (dot 4) and must not come into contact with motor oil. Hope this answers your question. Cheers Cooter