Omega Speedmaster Professional - O-ring gasket sizes

Can anyone tell me the size and thickness of O-rings or gasket that I need for my 1996 Speedmaster 861 with case back number 145.022.

I want to replace the O-rings in the crown (I think there are two), the gasket on the case back and the o-rings in the pushers (there are 4 in total). Is the anyone in Australia who sells these O-rings? Thank You.

I've seen sellers on eBay from Germany and Switzerland. The crown and pushers are replaced during service.

I am servicing the watch myself. There must be a diagram somewhere of the sizes required?

As mentioned in your last thread, the gaskets in the pushers and crowns aren’t sold separately. Omega expects that the complete crown and pusher assembly is replaced so you won’t find measurements from them. You will have to pull the gaskets out and measure them to find replacements.

As for the caseback gasket, I believe the Overall diameter is 36.00mm and the thickness is 1.00mm.

I'm sure Omega has a very nice diagram with measurements and probably a parts list with dimensions and tolerances. They're for use by Omega and their contractors, not us. Omega directs the crowns and pushers are replaced entirely during service to maintain water tightness. As I mentioned, I've seen listings on eBay for "Speedmaster O-rings" from sellers in Germany and Switzerland. These aren't official parts because there aren't any but for a couple of pushers, probably listings born from those who want to maintain "originality" of their Speedmaster at any cost and found ways to service parts designed not to be serviced. O-rings can be measured, if you know how, maybe some of those sellers can help you as Omega will not and most of us here don't know the answer to your question. Maybe someone will come along who's seen this done.

For people's information and education purposes. There are two o-rings in the crown. The measurements are 3.8mm in diameter and 0.8mm thick.