7S26 Movement

[Ruffass]

Hello all,

I want to strip down and service my favourite Seiko 5 watch. Thing is I'm a newbie and Odds on I'll probably make mistakes. I'll be using various Vids off Youtube to guide me but if something does go wrong I might want to replace the entire movement as I'll possibly not be able to find the fault. I looked online and it dont seem you can buy replacements brand new. I was thinking about the NH36 movement as a replacement as they're readily available although what worries me is it's thicker and might not fit my watch case.

I'd welcome and be grateful for any advice.

Edited November 21, 2024 by Ruffass

[AndyGSi]

Don't know where in the world you are but 7S26 movements are still available, not cheap compared to what you can get a complete Seiko for.

It's common practice to use the NH36 as a replacement but you'd need to swap the day wheel from the 7S26.

[Ruffass]

Thanks for your reply Andy

I'm in Sheffield UK.

I was hoping to be able to get a replacement movement for around £35.

Not cost effective otherwise as like you say I may aswell get a new watch.

I think if things go wrong I'll just have to try and convert it to the NH36 movement which seems much cheaper.

 

 

[tomh207]

iirc you’ll likely have to swap the plastic ring that comes as part of these movements, black ring on the 7s26 and grey on the NH36 as well.

 

Tom

[Ruffass]

8 hours ago, tomh207 said:

iirc you’ll likely have to swap the plastic ring that comes as part of these movements, black ring on the 7s26 and grey on the NH36 as well.

 

Tom

Thanks Tom,

I was wondering if you have any experience doing this Conversion, maybe you could give me some advice if and when the time comes?

I would also be grateful if anyone could give me a pointer in the right direction in regards to obtaining genuine Seiko parts that sells to the UK public (not trade). A parts catalogue may come in handy aswell? I'm thinking for a new crown and stem. 

[AndyGSi]

11 minutes ago, Ruffass said:

Thanks Tom,

I was wondering if you have any experience doing this Conversion, maybe you could give me some advice if and when the time comes?

I would also be grateful if anyone could give me a pointer in the right direction in regards to obtaining genuine Seiko parts that sells to the UK public (not trade). A parts catalogue may come in handy aswell? I'm thinking for a new crown and stem. 

Cousins will deal with anyone but as Trade (so you don't get the same customer rights or something)
but it's never bothered me and I've only ever had 1 issue that was resolved without question.

I you looking at genuine parts for replacing on the 7S26?

Edit

Is it a 7S26-0480?

 

Edited November 22, 2024 by AndyGSi

[Ruffass]

Thanks again Andy.

When I tried signing up online they wanted me to confirm I had my own business. I also think they wanted a VAT number. Not sure if and how to get round that? 

[tomh207]

I haven’t done the conversion myself but have seen plenty of info online in doing this. Happy to help if I can though. I echo Andy about cousins, there are also HS Walsh along with Gleaves. Worth checking all three for price as sometimes one can be cheaper than the others.

i wasn’t ask for a vat number when I signed up for cousinsuk, it was fairly straightforward.

 

Tom

[RichardHarris123]

I think I was asked for a business address and vat number, if I remember correctly, I  left it blank and I was allowed to join. 

[Ruffass]

Thanks Tom, I've just had a look and it turns out I've successfully obtained an account with Cousins. I'll try them for the relevant parts.

Thanks, Ruffass

1 minute ago, RichardHarris123 said:

I think I was asked for a business address and vat number, if I remember correctly, I  left it blank and I was allowed to join. 

Cool, cheers for that Richard.

1 hour ago, AndyGSi said:

Is it a 7S26-0480?

Sorry just seen this edit! Yes it is Andy, and there's an F in a box next to this Number.

[watchweasol]

Hi Ruffass. Ther are also A.G.Thomas ( Bradford). And H.W. Walsh who are also material houses who deal amateur’s.

[RichardHarris123]

6 minutes ago, watchweasol said:

Ther are also A.G.Thomas ( Bradford).

Their website is dreadful, do you know if their stock is better than what is shown? 

[AndyGSi]

1 hour ago, Ruffass said:

Sorry just seen this edit! Yes it is Andy, and there's an F in a box next to this Number.

The crown would be a 9M40B3SNW0 and the F relates to the case construction as below.

[Ruffass]

45 minutes ago, watchweasol said:

Hi Ruffass. Ther are also A.G.Thomas ( Bradford). And H.W. Walsh who are also material houses who deal amateur’s.

Thanks watchweasol.

 

28 minutes ago, AndyGSi said:

The crown would be a 9M40B3SNW0 and the F relates to the case construction as below.

Thanks for the info Andy. Although I've had a quick google and it seems it wont be a straightforward job. I think the problem might be getting the stem and crown right. I might be better just trying to service the 7S26 and see how I go. I'll make a note of the Part number just in case.

[SwissSeiko]

I've done this swap and its very easy. You will need to replace the stem, since the NH has hand winding. Well worth the mod. It swapped in no problems. I cant remember if I had to change the spacer ring. 

[Ruffass]

3 minutes ago, SwissSeiko said:

I've done this swap and its very easy. You will need to replace the stem, since the NH has hand winding. Well worth the mod. It swapped in no problems. I cant remember if I had to change the spacer ring. 

Hi there SwissSeiko. Thanks for the info. Oh right so do I put the Original Crown on the new NH36 stem? Did you do the swap on the same model as mine (SNXS73)? Is there any cutting to size required? 

Many Thanks in advance!

 

1 hour ago, AndyGSi said:

The crown would be a 9M40B3SNW0 and the F relates to the case construction as below.

Thanks again Andy. I've just ordered the part from Cousins. £12 including P+P.

[AndyGSi]

29 minutes ago, Ruffass said:

Is there any cutting to size required?

No cutting required but if you do go for the NH36 you're best going for a NH36-3.8 so you don't have to mess around with the Day Dial.

[Ruffass]

Cheers Andy. Yeah I got the 3.8 NH36 coming from Ali Express. Only cost £25 in Black Friday Sale. Supposed to be Japanese but you never know. Hope it performs like a couple of my other NH35 Japanese movements which I've got in  Addiesdive and a Cestrian watches.

[spectre6000]

I did the 7S26X - NH family swap a few years back. First time I had done such a thing, so I was likely in a similar state of skill as you are currently. I had an old gray market 5 that bit the dust in a particularly nasty car wreck (fun times). I intended the resurrected watch to be a shop watch that would take irregular wear (and absolutely unconscionable abuse), so I went with a non-date version (NH39?) and didn't have to deal with any date complication complications. I also replaced the crystal and dial with aftermarket units. I don't recall any particular challenges related to the movements themselves save a vague recollection that I wasn't entirely comfortable with how tight the fit was getting the movement into the case. I don't have any clue if I used one movement ring or another, and it may not have even been the same watch I'm thinking of. Whatever the case, I went ahead with it, and I'm a famously cautious person with that sort of thing (me and torque specs are a running gag with the car club guys), so it couldn't have been that bad if I'm even remembering correctly.

[Ruffass]

Cheers for the info Spectre6000. Yeah I'll have a go at it. Cheap and Cheerful way of easing my way into working on Mechanical watches. 

Edited November 23, 2024 by Ruffass

[boogeez]

On 11/22/2024 at 8:45 AM, Ruffass said:

I think if things go wrong I'll just have to try and convert it to the NH36 movement which seems much cheaper.

 

 

I did the nh36 convertion of my Seiko 7005-8042. It was given to me by my dad a long time ago. Parts were hard to source or not available even in the service center here in the Philippines. I removed the grey/black ring and was able to use the original movement holder after grinding it.  I had to replce the stem but used the original crown. The watch dial also had to be replaced since I don't know how to recolor it. I buffed the acrylic starting at 600 grit to 5000 grit sandpaper. After buffing, I used cutting and waxing compound. Acrylic was clead again. So far It's still working and keeping +4 spd. Ok by my standards for a revived seiko watch from the 70's.