Repair + Service: Omega Seamaster “Bumper” calibre 354

I love bumpers – that unique back and forth of the hammer that winds the watch is very reassuring.

Simon sent me this one, and the winding stem comes straight out when I unpack it.

A fair amount of scratches on the plates. They look pretty random, and I wonder how that happened. Nothing serious, though.

No wonder the winding stem comes straight out. The set lever is broken off, and the set lever spring is bent. Looks like someone really really wanted to get that winding stem back in…. The copper plating is coming of the bottom plate, but again, that’s no big deal.

That does not look healty… Hopefully, a good clean and a new mainspring will sort that out.

Time to take the movement apart.

All looking good – no more surprises here.

You can’t get the exact size mainspring any more, but I’m using a 1.10 x .10 x 300 x 9.5, and that works well.

The movement is coming together nicely, and it’s ticking already.

Now that looks so much better than before!

Oddly enough, the new winding stem is a bit too thick where the winding pinion sits. Not a problem – that’s what a lathe is for.

The new set lever, set lever spring and winding stem back in place.

Dial and hands go back on – in very good condition considering the age of the watch.

With the movement back in the case, I put together the auto-winder with the hammer.

I managed to get hold of the exact original crown for the case.

That does look nice!


17 thoughts on “Repair + Service: Omega Seamaster “Bumper” calibre 354

  1. The escape wheel of my Omega seamaster (calibre C-2576-70) selfwind
    watch without day&date,has been damaged and needs replacement with
    a new one.The escape wheel is not available anywhere and I am fed up
    with my futile try.Any escape wheel of other brand watches will suit?If so,
    please let me know.Looking forward to your reply,Thank you,

  2. Hi, I have this exact omega (except the indices on my watch are gold tone) I saw your price is £150, Is that for a full service? I would only like the movement serviced, I am quite happy with the case and dial in its current state.

  3. I have very Much part part for omega 351,352,355,565,501,500,503.1040.1045.861.321.911.920,980 n Etc pin bb 21670f76 n WA 081514417275 Jakarta

  4. Hi Christian

    I recently acquired a seamaster bumber cal 353 Omega in a 2627 case with the date at 6 o’clock. It does not have its original crown and I have found one on the Otto Frei website that I think is the correct one but wanted to check with you as you have just done this very similar watch. The spec is Diameter 5.40, tube opening 2.0 mm, tap 10 (0.90 mm)., is this correct?



  5. That movement looks very similar to my Tissot bumper from 1947 (Tissot and Omega shared movements at that time). One minor difference is that my bumper movement has little springs to provide cushioning at the end of each bump. Are the springs missing from this example, or is there no provision from them.

    Love, your blog by the way. I have no watchmaking skills but have a small collection of vintage watches and love seeing how you work on them.

  6. I’ve never really liked the idea of bumpers; my instinct is that something percussive going on in a precision movement can’t be good… do you ever see any issues associated with this or am I just being paranoid?

    Is there a standard way of determining what would be an appropriate replacement mainspring – maybe a list of equivalents – or do you just have to find whatever is dimensionally closest?

    It is indeed a lovely watch 🙂

    • I’m sure the bumper isn’t the ideal way to wind a watch, but there is just something to it that I like. They are quite accurate, so I don’t think there is too much of an issue with the vibration.

      You just measure the height, thickness and length of the mainspring, and normally, you can get just that. Unfortunately, for the bumper movements, they are out of stock, and I tend to buy one that is just a tiny bit thicker (0.05mm), as the original thickness isn’t available any more.

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