Yuck!
The 9-speed brifters on my trek had developed the nasty habit of not downshifting, but instead just flapping uselessly in the wind whenever I hit a ramp and needed to downshift, so I decided that instead of throwing them out or firesaleing them on ebay I’d attempt to disassemble them to see what was making them not work.
In a nutshell, they weren’t working because the grease in them had turned into tar, and it was keeping the downshift rachet from engaging properly. So I spent about 45 minutes this evening disassembling the shifter and cleaning out the masses of solidified grease.
The shifter is now in 50 or so pieces on my workbench, slowly drying out after a couple of cycles of El Duke, then water, then WD-40 to drive the water away. I will probably nail it with a round of citrus degreaser tomorrow, then repack it with teflon-loaded grease when I try and put all of the pieces back together.
(The mechanism in these brifters is really pretty to look at, and I suspect I could actually modify them to do handlebar routing of the shift cable (like Campagnolo and Sram(?) brifters do) which would be nice because it would give me the pivoting brake lever mechanism that I’m now used to and a nice open space between the horns of the handlebars for wedging various handlebar bags. But for now I’ll just be happy to be able to put the whole shebang back together and have it work.