This is a partially disassembled Shimano RSX right brake/shift lever from my road bike. The shifter has not worked for a long time. In fact, a few years ago I brought this to a bicycle shop for repair. They said it was impossible to fix these shift levers, and implied that I should just get a new bike. Instead, I asked them to replace the shift function with a lever on the down tube. (Old fashioned, but cheap and functional.)
I recently discovered a YouTube video that describes how to repair such a shifter by cleaning it with a spray degreaser. No disassembly required! How cool is that? I wanted to try it.
So, following the instructions in this video, I started spraying it out and and clicking the levers, spraying and clicking. Nothing happened. I accumulated a pool of degreaser, but still the thing would not click. Then I noticed a piece of the old shifter cable jammed inside. Turns out the previous mechanic had simply cut the cable, instead of pushing it through to free up the cable stop.
I knew I'd have to take it apart to get that cable out.
So I found another video about disassembling these things, and followed the procedure. I removed the dust cover (a) from the brake lever (b) and discovered another problem: a missing spring that's supposed to fit into the hole in the brake lever (b). This spring keeps tension on the shifter handle. It makes me wonder how the shifter ever worked, or how the spring came to be missing. Maybe the previous mechanic had taken it apart to get at the cable, and the spring flew loose. Who knows?
I removed the brake lever (b) from the shift assembly (c). At that point I could remove the jammed piece of cable. Part (c) was still gunked up with old grease, so I continued to clean it out.
I eventually realized that the shifter would never work without that missing spring. So instead, I found a used shift lever on eBay. The price was reasonable, so I ordered it.
The thing on my kitchen table? Just a bunch of shiny old spare parts.