Repair + Service: Omega Seamaster 166.0266 calibre 1020

Peter sent me this Seamaster – it does tick, but barely, and he would like it serviced and repaired.

So let’s see what’s inside …

The crystal isn’t original, and the glue has discoloured and come off in some places.

This doesn’t look great.

I take the movement out and start off with the bottom plate. I can already see a lot of rust on the winding stem side – looks like water ingress through the crown. Also, check out the date wheel. The tooth next to the 21 is missing – something I only notice much later when putting the movement back together.

That’s a lot of rust. The crown wheel is so badly damaged that it will need replacing.

Now to the top plate.

The winder transmission wheels are super-rusty as well.

Dirt and rust everywhere.

Oh dear.

Reassembly starts as usual with a new mainspring.

The wheel bridge in place.

All the rusty wheels are cleaned up using 9 micron lapping film.

That looks a lot better than before!

And the movement is ticking again.

As I put the movement together, I notice that the tube at the centre of the plate has come loose! ยฃ10.40 on eBay later, I have a new plate on the table. The new parts (shock spring and crown wheel) have arrived as well.

I reassemble again with the new plate.

The new crown wheel goes in and I start on the bottom plate.

The new (used) date wheel is in – with a tooth next to the “21” ๐Ÿ˜‰

The case has quite a bit of rust damage that won’t come off. Old and new case back gasket for comparison.

Cased with a new crystal.

The new, original Omega crystal looks a lot better than the one that was in there beforeย  – again, another great job done by Watch Glass Cutting UK Ltd.

An epic job comes to its end.

15 thoughts on “Repair + Service: Omega Seamaster 166.0266 calibre 1020

  1. Hi Christian.
    (I have asked this question already on your 1012 service, but this one shows up my query more clearly, if you decide to publish this comment please feel free to delete the other, and this bracketed text)

    The last of the winder transmission wheels interacts with a spring. Upon your first reassembly above it sits held away from the ratchet wheel. On your second reassembly it sits held against the ratchet wheel. Is there a correct and incorrect way to position the wig-wag spring against the screw on the last wheel?

    Thank you.

    Ed

  2. Very nice job as always! I just serviced the same watch though my crystal is cracked! Is there any way you could point me in the direction of a replacement crystal?

  3. Hi Christian. Nice Job. I bought the exact one (Omega Seamaster 166.0266) but the dial was already repainted. What’s worse is they redid the text by hand and it looks horrible. I wish to replace the dial that came with my watch. May I know where I can purchase a dial for that particular watch?

  4. Good Afternoon

    I’m trying to restore an Omega 1310. Looks like the coil has been damaged and has been patched by some Ag paint. It no longer works. I’m looking for a replacement Cal. 1310 coil.

    My only other hope is to find a coil rewind service.

    Kind Regards
    Mark Ward

  5. I love omega watches I own 3 (Professional speed master “The first watch in the Moon” 2nd. 1970 omega cal. 1020 automatic and 3rd. one omega megaquartz 32KHz cal. 1310 great watches

  6. Pingback: My Watch History.

  7. Great work. I keep reading your blog, hoping that one day I can get my hands on a Rado Catain Cook MKI and have you work your magic. Keep it up buddy!

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