[Bobcat]

A "secret" we used in rebuilding hydraulic valves when installing the static seal O rings was to use a light film of liquid soap on the O ring . It gave it lubricity and would stick the O ring to the metal as it dried out .... plus it was compatible with the hydraulic oils we used . Even works great as a bead lube when mounting a tire .
Some of those O rings can be a bear to get where they are supposed to be.