The o-rings are dust seals. Stretching them across the threads to
slide them on seems to give them a rather short lifespan. My first
one to go lasted about 2 months and I removed the other one while I
was in there. The local hardware stoor didn't have a goot
replacement so I left it without the o-rings for now.
This may help with the cover moving...
There is a sliding ring that the five (or is it six?) pressure pins
go through. On my G11 the placement of it was critical to prevent a
loose or binding cover. Also note that the lockdown screw for that
ring needs to match up with the flat area (I missed that the first
time). Good luck.
