WS 7: Vintage Omega Seamaster Gasket Ring Replacement
Selecting the new O-Ring
Select a slightly smaller size then the diameter of the groove. If the O-Ring is too large, the risk is very high that it will be twisted or even worse, squashed or cut when you close the case back. A little tension on the ring make sure it stays snug in the groove.
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The new "Swiss Made" O-Ring is inserted

This picture does not show how to apply grease, it
demonstrates how to take out a small amount of grease. Instead of smearing large
quantities of grease on the O-Ring inserted, use a small amount of grease
between your left thumb and index and carefully slide the O-Ring through your
fingers. That way a nice thin film of Silicone grease is applied.

The same applies for the O-Ring in the crown. Take the
ring out and take a small amount of grease and "massage" the ring between the
fingers until a small Silicone film is applied.

The grease is now applied as you can see from the gloss on
the ring just above the crown