New ones aren't that expensive. I don't think I've ever seen a kit for a master or a slave. I bought a new slave for my previous '80 240D for a little more than $40.

Here are a couple of choices:

Fastlane - $73
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1EO12NRRP1EV0P9066&year=1981&make=MB&model=240-D-002&category=I&part=Clutch+Master+Cylinder

************************ - $62
http://www.************************/ProductPage.aspx?ProductName=Clutch+Master+Cylinder&productid=101584&producttype=40

*************** (Rusty) - $64
http://catalog.eautopartscatalog.com/buymb/wizard.jsp?partner=buymb&clientid=buymbparts&baseurl=http://www.***************/&cookieid=1EV0PI2MD1EV0PI717&year=1981&make=MB&model=240-D-002&category=I&part=Clutch+Master+Cylinder

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)