There are 2 types of use for o-rings:
1° sealing by compression (back door of the housing or light canisters for example)
2° sealing turning things (like knobs, dials, ports, etc)
Grease on o-rings working by compression is not very important as there is no friction, and lowering friction is the reason for the grease.
Grease on o-rings sealing turning stuff is very important to reduce friction as the friction will reduce slowly the o-ring diameter.
Basic rubber orings can benefit of silicone grease as this grease avoid that they dry out and start to develop fine cracks
In all the 10 years i never flooded a camera because of the lack of grease,
the only thing i flooded was one of my Z-240 strobes as i pinched the o-ring while screwing on the battery cap.
This would have ben avoided if i had greased the o-ring before screwing the cap on as the lubrificated o-ring may not have become pinched from the turning movement.
Hugyfot says that their red o-rings don't need lubrification so i never lubrificate them, the black rubber port o-rings get lubrificated if i switch ports
To lubrificate a o-ring put a tiny amount (pin needle head size) of grease on your clean index finger,
rub your index finger and thumb to distribute it evenly and turn the clean o-ring between your fingers so that he becomes shiny but no grease is visible.
Clean with a lint-free towel (for lens/eyeglasses use) the groove where the o-ring seats and push the o-ring back in it's seat.
Doublecheck if the o-ring is seated well!
Unfortunately most of the o-rings sealing turning or sliding axles/pins are so hidden and inaccessible that you need to disassemble them completely.
A quick and dirty fix for sticking buttons is to use a toothpick or paper clip to smear a very small amount of grease to the pressed down pin of the button.
Release the button and press/release for several time to see if the button is sliding better.
The buttons and dials of housing should be serviced each year and this is not a simple task as you need to have good micrometric skills to remove the c-clips
holding the pin/axle in place. You need also a kit of new c-clips, watchmaker tools, new o-rings and maybe new springs too.
And for some housings (Nauticam) you need a very good memory to remember how the parts where assembled.
A vacum leck detector will help greatly to avoid a flooded rig!!!
Edited by ChrigelKarrer, 11 March 2018 - 12:47 PM.