Kinda late but this might help others who have popped their Z57.
Some additional info.
opening a Z57
- Seal in a small Ziploc bag and boil for a few minutes, or use a heatgun to heat the switch.
This will loosen the Loctite on the threads.
- Grip in a beltwrench and use needle nose plyers or a Shimano TL-FC20 peg spanner to twist.
Search
here. These fit the notches in the retaining ring perfectly. In the above pic,
note that some material has been removed between the points but this is not necessary.
You just need to squish down firmly on the rubber boot.
Be careful as the tool will slip easily and scratch the HA finish.
BTW all this info was compiled from the following great threads, an example of sharing knowledge and
making the world a little bit brighter, CPF at its best.
If you have a stiff Z57, you might find some valuable information.
I want to fix your stiff L4/Z57 "clickie" switch! by LitFuse
Check post #29 and #77
L4 clickie repair instructions.. by JHanko
This is the broken link in post #77 above and is where
Ratdog introduced the source for the washers (post #13).