We do offer a small parts service kit for the R2C shifters:
11.7015.075.000 R2C Shifter Front/Rear Service Kit
To see the exploded diagram of all the parts included with this kit, please see page 28 of the current SRAM spare parts catalog.
All SRAM spare parts can be ordered through your local bicycle dealer. Please bring the part number to your local bicycle dealer, and they can special order the parts for you.