Case back seals

[Chief]

I'm looking to replace the case back seal on a watch, when I removed the case back the seal was twisted and crimped in 2 places. The seal looks flat, but when I've looked for replacements I've noticed there are flat and o-ring style seals available. Would I be best going for a flat seal again? Is the original seal actually flat or is it a completely worn out o-ring?! Do they come in different thicknesses? Is there a way of finding the original part numbers of case and strap parts like there is with movement parts?

[mikepilk]

What is the watch? It's hard to help if we don't know what the watch is.

13 minutes ago, Chief said:

Would I be best going for a flat seal again? 

If that was the original seal, yes.

15 minutes ago, Chief said:

Is the original seal actually flat or is it a completely worn out o-ring?!

Don't know unless you can provide pics.

15 minutes ago, Chief said:

 Do they come in different thicknesses?

Yes they do.  Have a look here https://www.cousinsuk.com/category/watch-gaskets

16 minutes ago, Chief said:

Is there a way of finding the original part numbers of case and strap parts like there is with movement parts?

Possibly, but we would need to know what the watch is to help.

[RichardHarris123]

Yes, try to replace like for like. An assorted set us £4.50.

[Chief]

2 hours ago, mikepilk said:

What is the watch? It's hard to help if we don't know what the watch is.

If that was the original seal, yes.

Don't know unless you can provide pics.

Yes they do.  Have a look here https://www.cousinsuk.com/category/watch-gaskets

Possibly, but we would need to know what the watch is to help.

Sorry, I should have known to give some indication as to what it is! I've added pics of the seal and case back. The watch is a Citizen Promaster Wingman Temp. How would I go about identifying the correct parts for it? I've measured the case back diameter where the seal sits, but how would I know how thick the seal is to be?

[RichardHarris123]

Measure the thickness or buy the selection. 

[Chief]

Just now, RichardHarris123 said:

Measure the thickness or buy the selection. 

Thanks Richard, I think I will get a selection. But my question is, how do I know that the thickness of this seal is the correct thickness a new seal should be?Could this seal not be worn out and flattened? It's been in the watch for 20 years. I'm also after other parts which I can't seem to find like a bezel insert which is why I was asking where people source case parts from. Is there a way of seeing exploded diagrams of cases with part numbers?

[rjenkinsgb]

There is a section in this Citizen technical manual that gives a breakdown of the number on the case back, plus a lot more useful info:

https://www.plus9time.com/blog/2021/10/3/citizen-technical-information-manual-mid-1970s?rq=Citizen technical

 

[watchweasol]

Hi @Chief  I have a copy of this manual picked up on the net but it’s too big to add the file it errors out so copy it to your system  from @rjenkinsgb link.  It does contain a lot of use full information apertaining to. Citizen watches.

[Chief]

14 minutes ago, watchweasol said:

Hi @Chief  I have a copy of this manual picked up on the net but it’s too big to add the file it errors out so copy it to your system  from @rjenkinsgb link.  It does contain a lot of use full information apertaining to. Citizen watches.

I've downloaded it from the link! Looks like a really handy manual. However it doesn't help with sizing the case back seal. It does tell me it's a flat seal which is good! I think I'll go for an assorted pack from cousins and see how it goes!

[Neverenoughwatches]

9 hours ago, Chief said:

Sorry, I should have known to give some indication as to what it is! I've added pics of the seal and case back. The watch is a Citizen Promaster Wingman Temp. How would I go about identifying the correct parts for it? I've measured the case back diameter where the seal sits, but how would I know how thick the seal is to be?

With something like this a gasket seal for instance if i cant find the relevant information i would use instinct to decide what fits and works best. You have the original gasket ( well maybe its original or hopefully it is )so its fairly easy to determine what material to use. Shape , for that i would look at the gasket seatings, are there grooves or recesses in either the case back or case or both, what shape are the grooves, flat or round etc, how does the gasket sit and behave in those seatings. Next thickness,that is going to be a bit of a guess, especially if the gasket is a soft one that has been heavily compressed over time. This is where a selection is going to come in handy, personally i would be choosing one that is giving me the feel of compression as its coming into contact with both of the mating surfaces. But not so much that the gasket is going to squash out and become distorted, again this is guesswork and feel is required with the allowance of compression over time, something you may want to check after six months. This part is a little moot as without a pressure test, good water resistance is not assured so the watch needs to treated as such and not as if it were a new diving watch ( not that i would treat any new diving watch as if were ). What you want to expect from your efforts is a little accidental rain catch, if you want more water resistance guarantee then a professional gasket replacement and pressure test is what you should be seeking which will be more than the value of this watch. Coincidentally i have the same watch, been searching for a stem for it for a while now. 

[Chief]

12 hours ago, Neverenoughwatches said:

Coincidentally i have the same watch, been searching for a stem for it for a while now. 

Oh really! Maybe you can help further then. I'm going to restore the case, it's not in bad condition but I want it to look original. The underside of the case has a high polished finish but the top looks brushed. The bezel also looks brushed. Do you know if it should be a brushed finish on top and bezel? Or should it be polished like the under side?