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For the second time now, I found the clutch fluid reservoir to be empty after sitting unused in the cold for a month. The first time, I refilled it and it stayed full all summer being used daily. Now it happened again after sitting unused in the cold for a month.
The thing is I can't see any signs of where the fluid actually went. Any ideas?

Back of master cyl or slave cylinder seal leaking.
Rebuild them both for best results.

Thanks Jim. That's what I was thinking I would do next.