Working on bar end shifters

Does anyone have a set of instructions for serviceing bar end shifters similar to what is on the park tools web site?

I’ve checked park tools and sheldon brown as well as doing a basic web search. Also, shimano only has a diagram of the shifters, not a service manual available on their web site.

Or, are these just parts that you don’t work on?

The technique to work on these shifters is a closely guarded secret grasshopper. Once you figure out on your own how to take off the handle, loosen the shifters from the aerobars, replace the cable, reattach everything after scratching your head over that little square plastic spacer, you will find that everything works great except for the clicks.

Return then for you next lesson on slackening cable, diddling with spacer, and all will be wonderously revealed.