I made sort of a sudden, hard, and frightened right lever shift
yesterday and suddenly the righthand lever/shifter would only let me
shift up one gear at a time. Shortly afterwards, the brake lever would
not release entirely - the top of it was about half a cm forward of
where it should be. I stopped and found that the back part of the
plastic cap - by cap I mean the plastic part that says Sora on it - had
come loose and was wedged in the lever. I got it out - it's a small,
roughly c-shaped piece of plastic - but cannot figure out how to
reattach it.
Over several hours of fiddling, I managed to the the darn thing in place
several times, but it simply won't stay. I cannot see anything that
indicates that the thing was once glued to the bigger cap piece.
There's one little plastic "pin" sticking out of it, but that doesn't
seem to be enough to keep it in place.
I checked the exploded view of the lever on the shimano site -
http://bike.shimano.com/product_images/ST/ev_images/ST_3300&3303_EV.pdf
and it doesn't give this little loose piece a separate part number.
The lever and shifter still work, I just cannot shift up (i.e. to a
larger cog) more than one at a time.