Originally Posted by Drew Eckhardt

The small parts were discontinued for the Ultrashift (third generation) levers and were never available for Powershift or Escape levers. Replacement assemblies consisting of everything but the brake blade, hood, and mounting hardware are available for about $100 although that's a far cry than the $5-$10 you'd spend to replace the parts which usually broke or wore out in first and second generation levers.

First generation small parts (apart from the G-springs and left G-spring carrier which are common to second generation levers) have also been discontinued.