Gemma_k put it thus -

I actually took apart one (RH 10sp Chorus Carbon) has weekend, put in it new
G-Springs and main spring. Good as new.


It seems to me this ability is the only real world difference between C and
S group sets.

Wear out the return spring in one Shimano lever (as you surely will) and
prepare to get hot under the collar about having to replace both *SETS* of
levers.

Worst example of price gouging I have ever experienced, and the automotive
spare part manufacturers are bad* but that silly spring fiasco is the all
time world champion.

best, Andrew

*[warning 4 wheel bit follows- block the kiddies eyes and ears-
Replacement brake master cylinder set for a lexus $2450 plus gst
Same part, under a different number for a Toyota Camry - $258
Be nice to the guy behind the parts counter, he may have valuable wisdom]