Originally Posted by
FBinNY
or buy a stronger return spring if one exists.
AFAIK, you can't replace that spring on any common derailleurs, even Campag.
The trick is to jam something under the end of an axial spring... for linear springs, I'm thinking binding some coils together with fine wire might do it.
But it's a last resort... take your cable off, and if the inner isn't stainless, turf it for a proper one. Use the tube on your WD40 can to squirt into your housings and flush em good.