How it works
Old bushings are often hard and damaged. This results in
harsh/clunky keyboard feel,
uneven key height and uneven key spacing. The new bushings do the following:
1. dampen key down presses
2. dampen key up releases
3. center key left to right
Here is a simple drawing of the two forces damped by the bushing.
The bushing also serves to center keys left to right.
Replacement is simple:
1. Remove plastic key top (remove screw)
2. Pull off old bushing
3. Push on new bushing.
4. Re-install plastic key top.