Clutch slave cylinder questions

[seniorchristo]

I am rebuilding my clutch slave cylinder and have a couple questions. What is the little black rubber washer for, from kit supplied by RD Enterprises? Also, how does the supply line fitting seal? Does it seal at the the tapered seat or by the copper washer? The washer was setting on my work bench and I don't recall seeing it when I removed the fitting.
Thanks,
Chris

[billwill]

See this recent topic:

lotus-gearbox-f37/clutch-line-help-please-t36208.html

[seniorchristo]

Thanks Bill. Still wondering about the extra washer. It's not shown in the Elan manual.
Chris