Service: Seiko Bellmatic 4006-7010 calibre 4006A

IMG_0041Christian sent in this Seiko Bellmatic for a case polish and service.

This is an alarm watch with day and date display, so a fairly complex beast. The movement itself can’t be wound with the crown, but only the alarm. The crown has three positions – pushed in to wind the alarm, middle position to set the alarm, and pulled out to set the time and date. The pusher at 2 o’clock switches the alarm on and off.IMG_0043

The movement has 27 jewels.IMG_0045

The usual Japanese way to construct and auto winder.IMG_0049

The dial and hands do not only look good, but are in great condition as well.IMG_0052

The date ring has some discolouration and damage, but I can get hold of a new one.IMG_0059

Under the date/date layer lurks the alarm mechanism.IMG_0066

No lack of complexity here.IMG_0078

Now I can turn my attention to the movement itself. Note that the alarm spring doesn’t have a barrel, but is set directly into the plate.IMG_0082

As you can see, there is no lack of parts.IMG_0186

I start off with a new mainspring.IMG_0189

I start off with the base movement.IMG_0198

Putting together the bottom plate is the time consuming bit.IMG_0199

The old and new date ring.IMG_1300

Back together.IMG_1301

Charles did another great job polishing the case and bracelet!

49 thoughts on “Service: Seiko Bellmatic 4006-7010 calibre 4006A

  1. Very nice work! I would appreciate if you could let us know which main spring you used, dimensions or parts number at Thanks!

  2. I have what appears to be a dolphin back 4006-7000. I’ve been informed that it is a watch that is often repaired using incorrect parts. What would it cost to verify it’s authenticity? Also, in the event that incorrect parts are found upon inspection, do you have the vintage parts to bring it back to authentic?

  3. Hi Christian,

    Considering that amplitude for these 4006 movements is lower than Swiss watches, what would you consider normal or ‘healthy’ amplitude for this movement, and at what point would you say the amplitude is ‘poor’?


  4. Hello,
    I have this exact same watch, which has not run for quite some time. A nearby watch repair shop took a look and unfortunately lost a screw.

    Could you possibly estimate what it would take for you to get it running and replace this screw?

  5. Pingback: The Seiko Bell-Matic 4006-7010 27 Jewels – Ding-a-ling-a-ling!!! | musingsofawatchaddict

  6. Can you service my 4006-7010 Seiko? It’s works good but needs cleaned up and giving a once over,I live in Ohio US !

  7. 09/26/2017
    Hello: I have a Seiko Bellmatic from 1970 that needs to be repaired. Do you know anyone who repairs these watches? I tried to contact Seiko North America and they do not repair them again? It has not run in a number of years.
    Thank you for any help.

  8. I was reading a blog you posted about Bellmatic watches and have a question.
    I bought my Seiko Bellmatic on Okinawa in 1970. It runs, alarms, etc but it needs a face lift. As you might imagine, I don’t wear it often any longer; however, I would like it to be “like new” again (if possible) … but … don’t know where to turn. Can you help?

  9. Hi,

    I have an original seiko 4006-7001 (waterproof written on the back). I received it from my grandad. Highly sentimental. Unfortunately, it’s not working anymore. I visited repair shops in mtl and all told me it was impossible to have it fixed because there is no more parts for those.
    Do you know where I could get the parts or have it repaired ? I’m in Montreal, Canada. Thanks. As i’m a bit bit desparate, I thought I would ask !

  10. Hi,
    I have a 1967 Seiko 4006-7010 27J that no longer runs. The alarm will ring if the dial turns but the hands do not except for maybe a 5 or 10 seconds after fiddling with the knobs. Is there any way for you to estimate the cost of repair?
    NH, USA

  11. This is actually my watch that Christian serviced. I removed the strap to keep it in good condition and have the watch on an auto winder. I have worn it once a week or so since I have got it back from Christian. As you can see he did a remarkable job on it and the most amazing thing is the time-keeping is extraordinary accurate. It gains about 4-6 seconds a week, thats it! I have put a new Hirsch brown leather strap and it looks gorgeous and oh so practical with a very good alarm. I completely recommend Christian as the person to go to for servicing and restoration. Just superb. The watch in question may be available for sale. If anyone is interested please drop me a line.

    • Hi Chris,
      I’m guessing it’s a bit late but is this watch still for sale? If so, let me know at I was looking to get mine serviced but you’re is a) nicer, and b) black faced against my white faced model. It’s a shame Christian has such as backlog of work but that’s a great recommendation too!
      All best

  12. Proud owner 4006-7011 works perfectly I had it cleaned and serviced but the tech could not locate a new o ring to keep water out He couldn’t locate a new one Do you have a source for one

  13. Hi there,
    I had a hard enough time finding a freshly serviced Bell-matic 4006a-7010 for a reasonable price, only to get it after 4 weeks from the Phillipines and the sweeping second got stuck at the glas each rotation…grrrrh!Now I´m waiting again 2 weeks, because the dealer who sells Rolex,Tag Heuer, Omega ect. does not have the skills to change the glas on this even though it used to be a Seiko dealer. At least because of its Seiko history, the shop has a fitting acrylic glas on stock.
    Anyways…I´m missing the usual screenshot that shows the amplitude,beat,hertz ect at this/your posting…was it that bad?

    Cheers from Germany
    Tobias Hommerich

    PS.:Sie machen wunderbare arbeit, die ich sehr bewundere und vielleicht werde ich noch auf Sie zurückkommen mit einer meiner Uhren.
    Btw:Was führte Sie in regnerische England?

    • Seiko watches tend to have a pretty bad amplitude, so I don’t find it worth showing that on the blog. Not much you can do, that’s just the way Seiko movements are constructed.

      PS: Meine Frau ist Englaenderin, und ich bin ihr hierher gefolgt.

      • I just realised that its “glass” not “glas”…doh!

        Is a bad amplitude not improveable by using a softer main spring?


        • A softer (e.g. thinner) mainspring will give less amplitude. Generally, you don’t change the dimension of the mainspring. Seiko makes movements with a very low amplitude, and so be it… If you want a larger amplitude, buy a watch from another manufacturer 😉

  14. Nice example!
    I had to dive into my archive and behold: A Seiko 4006-7001 with the same 27-jewel movement was awaiting! I like the style of the one featured here better. A lovely chunky case!
    Picked mine up early in my collectors time but it fell of the radar since I could not work out how to wind it properly 🙂 Now I know the reason also for that……

    Does anyone know the recommended procedure to set the date and day correctly?

    • Setting the day and date is a bit of a pain. When you adjust the watch backwards, only the day, but not the date changes back, and it’s in that way that you can get the right day/date combination, and than adjust forward until you hit the current date.

      • On mine one pulls out on the top button to turn the alarm on. What I found out after I owned the watch for a while and tried setting the date the hard way was the alarm button also acts as a date quick set if one pushes it in all the way. Try it. YMMV.

          • Ahhh! I knew the Japanese would have some tricks up their sleeves!
            Thanks for enlightening us Jason 🙂
            Mine also quicksets the date in the same way.
            Put mine on my timegrapher and it is obvious that it will need some work done to it. 150 degrees amplitude and 8ms beat error +250s / day. Not high up on the priority list but maybe one day?

    • Hi Dan,

      You have a second “mainspring” that drives a wheel that looks a bit like a star. The spokes of that star make a little hammer go back and forth – just like the escape wheel makes the pallet fork go back and forth.

      Under the hour wheel, you have a disk that rides up a bit when the alarm time arrives, thus liberating the hammer, which can then swing freely and hit a little spring to make the noise.

  15. Wow! It looks absolutely stunning! Amazing, and just fab to watch the tear down and rebuild. Makes it much more interesting for the customer and your growing band of followers. I cant wait to receive it This was my Father’s watch for 30 years.

    Many thanks Christian

    Many Thanks.

  16. I have a 4006 BellMatic – didn’t realise they were quite so complex! Recently the hour and minute hands have stopped moving, but the seconds hand ticks away merrily – strikes me this may be somewhat serious ;(

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