When I replaced mine, there wasn't any signs of fraying, only hardening of the rubber. Since they are press fit, loss of elasticity causes them to seep.

This is the hose you want:http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=2100LE29A2190ROWR7&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1985&product=D1030-21332&application=000005201 290mm/12in is plenty.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )