Z-axis Counterbalance Grommet Leak

Hello All,

Please see the attached photo.
I have an air leak coming from the top of the Z-axis on our Brown and Sharpe Global. The leak originates at the rubber grommet that the arrow in the photo is touching. I have cleaned the area, and can move the grommet in such a manner that it will stop leaking (or at least I can't hear it anymore).

Does any one know where I could find a replacement grommet?
Hexagon wants to come out and replace the entire counterbalance for a large sum of money, being that they do not stock just that grommet.

Seems like one should be able to replace just this grommet.

Any thoughs?

Thanks.
Array