Those leather seals are available, I got a couple off of eBay a couple of years back. IIRC, someone posted here that Silca, under the new ownership, was selling them again.
[MENTION=47570]Barrettscv[/MENTION], I am pretty certain that a Co-op would have some old main tubes, or even a few complete pumps that have other parts broken or trashed. The length of you existing main tube needs to be matched if its a frame fit model, I just sent my Silca to Grady (gomango,) and he fitted a longer tube from local Co-op to the workings so it would fit his frame.

Bill