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Discussion Starter · #1 ·
hey, fellow WUSers - I'm a big fan of citizen's monobloc cases that were used in several of their watches from, I believe, 1990s. I own three (two GMTs and a perpetual calendar model); unfortunately it seems that one of them is not water proof any more and caught some water - underside of the crystal became milky.

do you know how to open these cases?
All i found is that they are open from the crystal side - but I cannot even remove the bezel. Do I need any special tools?
I thought it would be sufficient to just pry the bezel open, but it holds strong. Is there any repair manual for these cases? Do you know how to remove the crystal?

ref number is BJ90xx, here's a photo for reference:

 

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You will have to remove the bezel. You will need to use a slim knife blade to pry the bezel off. I would put a thin tape on the blade as not to damage the watch. You may want to consider having a watchmaker do the work. Good luck.

Regards,

Ren
 

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Hi there beceen , i have a similar problem with mine something on the crystal , Please let us know how you get on if you go ahead . DW.
P1040354 (480x640).jpg
 

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Yes, the bezel got to come out first before you can access the crystal and movement.
Citizen bezel are definitely more difficult to remove thsn Seiko ones.
Some prying and correct twisting force needed. Careful on scratching the case.
Progressive and even gap prying with different thickness knife may be needed to prevent bending the bezel.
 

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Discussion Starter · #5 ·
Thanks for all your replies, guys. You motivated me to try again:p

So:
what can you do on a nice Friday night? disassemble a monobloc case, that's what!

Step 1.

get yourself a citizen-monocoque-certified pro bezel remover. Alternatively you can get a thin knife - I used a standard victorinox swiss knife.

Step 2.

Bezel removal. Insert blade between the case and the bezel - it's extremely tight, much tighter than on seikos I modded, but it can be done.
I guess it's safest to insert the blade between lugs - I chose upper lugs (12 hour mark), so I won't see all the scratches I made.

Now PRY! PRAY! PRY! and pray again not to damage the case. You can try to use tape to cover the blade, but it didn't work well for me.
Once the bezel pops off a little you can use something blunt to pry it safely finally - I used the swiss knife bottle opener. I also opened a beer with it afterwards, but that's optional.

here's the watch with bezel removed:



and rotating system inside the bezel:





Step 3.

Crystal removal. Once you get the bezel off the watch, you'll see a retainig ring that holds the crystal in place. Actually that's one part, but I guess you can push the crystal out of its frame.

Insert blade between the retaining ring and the case and pry:



It sits very tight, but use all your persuasion skills, and it will finally pop off.
In fact, you don't want it to pop off literally as it will send the dial and gaskets flying around your room (I tested that, so you don't have to). So be CAREFUL.
And try to SLOWLY pry the case open.

after you find all the gaskets you should see something like this:





the black gasket is made of rubber and goes around the dial on the 24hrs/GMT internal bezel, which is also removable.
The white one is plastic and holds crystal in place. SO DON'T LOOSE IT. No, seriously, don't.

here's a picture of all parts I disassembled, left to right: watch->24 hrs bezel->rubber gasket->crystal with white plastic gasket->bezel:




put your case with dial in some safe place - cleaning the dial from dust and other specks is a real PITA.
I used some mega pro dial cover machine:




Step 4.

Clean the crystal. I used some alcohol-based cleaner since no AR coat here.
Here you can see the difference:



Step 5.

Reassemble.
I found it extra hard to put the crystal back - the plastic white ring is fragile, it bends easily. And you have to put the crystal back perfectly as the bezel won't hold otherwise.

Step 6.

Rejoice!




thanks for your help, guys. After doing this I really came to think that this watch was not meant to be opened; everything sits very tight in its place, gaskets are very fragile - especially the white one, putting crystal back is quite a hassle. But still, now go and crack your monocoques open! :-!
 

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WOW! Thanks for that beceen brilliant instructions and pictures as well , also what traps to look out for . Thankyou.:-!:-!:-!
 

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Loved the "how-to" beceen, especially the humor added here and there! And on a side note, i would love to see more monobloc cases from Citizen, there aren't too many available.

-Nathan
 

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Discussion Starter · #9 ·
glad I could help:]

there are several monobloc cases I came across:

- stainless steel ones (BJ9040, PMX56, BL0001); they come with different dials and bezels (worldtime, GMT, non-GMT, arabic indices or not). There were also two-tone (steel-gold) versions of the worldtimer cases.

Next, you have the BN0000 divers - they are also monocoque.

- titanium - the well known royal marine (BN0110, BJ9140), "ray mears", Antarctica and 4x4 models. Also different dial colors available. The titanium royal marine watches seem to be still in production and easily available, although a bit pricey. There are also radio-controlled ones (PMD56-2951/2).

some of these are JDM models for sure, but some of the BJ90xx range were available in Europe (I even found on in some Hungarian e-shop); Polish citizen customer service seem to know nothing about them, although they managed to find a capacitor for my colleague's Antarctica.
 

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Interesting to see how it is done - I had always gone on the assumption that removing the crystal on my BN0000 would be best left to the professionals as it required a proper press and tooling to remove/replace it properly.

As a thought though, if you do get moisture in a watch, if I have it correctly it should work to pull out the crown and leave it somewhere warm/dry for a few days to suck the moisture out - a warm airing cupboard in a box of dry rice or silica should do the job.
 

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Discussion Starter · #11 ·
Yes, the trick with rice could work if the water inside was clean and left no residue on the crystal. Mine was dirty on the underside unfortunately.
 

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Thanks so much for the instructions. With the crystal out, does the movement come out? This could be handy if the rechargable battery needs to be changed.
 

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Discussion Starter · #13 ·
Thanks so much for the instructions. With the crystal out, does the movement come out? This could be handy if the rechargable battery needs to be changed.
No, the movement stays in its place. I guess you need to take the hands off before releasing the movement, though I didn't try it. Plus I'm not sure how to take out the crown and stem, which is probably essential to take the dial/movement out.

Sent from my GT-P5100 using Tapatalk 4
 

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Yikes .. What a PIA this watch must be to disassemble. But, if you love it, or it's your livelihood (i.e , watchmaker), then you'll gladly endure the labor of love.

Sent from my SAMSUNG-SGH-T989 using Tapatalk
 

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Thanks for all your replies, guys. You motivated me to try again:p

So:
what can you do on a nice Friday night? disassemble a monobloc case, that's what!

Step 1.

get yourself a citizen-monocoque-certified pro bezel remover. Alternatively you can get a thin knife - I used a standard victorinox swiss knife.

Step 2.

Bezel removal. Insert blade between the case and the bezel - it's extremely tight, much tighter than on seikos I modded, but it can be done.
I guess it's safest to insert the blade between lugs - I chose upper lugs (12 hour mark), so I won't see all the scratches I made.

Now PRY! PRAY! PRY! and pray again not to damage the case. You can try to use tape to cover the blade, but it didn't work well for me.
Once the bezel pops off a little you can use something blunt to pry it safely finally - I used the swiss knife bottle opener. I also opened a beer with it afterwards, but that's optional.

here's the watch with bezel removed:



and rotating system inside the bezel:





Step 3.

Crystal removal. Once you get the bezel off the watch, you'll see a retainig ring that holds the crystal in place. Actually that's one part, but I guess you can push the crystal out of its frame.

Insert blade between the retaining ring and the case and pry:



It sits very tight, but use all your persuasion skills, and it will finally pop off.
In fact, you don't want it to pop off literally as it will send the dial and gaskets flying around your room (I tested that, so you don't have to). So be CAREFUL.
And try to SLOWLY pry the case open.

after you find all the gaskets you should see something like this:





the black gasket is made of rubber and goes around the dial on the 24hrs/GMT internal bezel, which is also removable.
The white one is plastic and holds crystal in place. SO DON'T LOOSE IT. No, seriously, don't.

here's a picture of all parts I disassembled, left to right: watch->24 hrs bezel->rubber gasket->crystal with white plastic gasket->bezel:




put your case with dial in some safe place - cleaning the dial from dust and other specks is a real PITA.
I used some mega pro dial cover machine:




Step 4.

Clean the crystal. I used some alcohol-based cleaner since no AR coat here.
Here you can see the difference:



Step 5.

Reassemble.
I found it extra hard to put the crystal back - the plastic white ring is fragile, it bends easily. And you have to put the crystal back perfectly as the bezel won't hold otherwise.

Step 6.

Rejoice!




thanks for your help, guys. After doing this I really came to think that this watch was not meant to be opened; everything sits very tight in its place, gaskets are very fragile - especially the white one, putting crystal back is quite a hassle. But still, now go and crack your monocoques open! :-!
This is great guide to follow up. Unfortunately, I don’t see any pictures.
 

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This is great guide to follow up. Unfortunately, I don’t see any pictures.
You should lower expectations when viewing a 7 year-old thread, especially after several image hosting services have began blocking hyperlinks to members image libraries.
 

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Discussion Starter · #20 ·
You should lower expectations when viewing a 7 year-old thread, especially after several image hosting services have began blocking hyperlinks to members image libraries.
well, since I cant edit the original post, let me upload the pics here:) I lost the original ones, but just took another watch and shot some photos. Hope it helps.


Step 1.

get yourself a citizen-monocoque-certified pro bezel remover. Alternatively you can get a thin knife - I used a standard victorinox swiss knife.

Step 2.

Bezel removal. Insert blade between the case and the bezel - it's extremely tight, much tighter than on seikos I modded, but it can be done.
I guess it's safest to insert the blade between lugs - I chose upper lugs (12 hour mark), so I won't see all the scratches I made.

Now PRY! PRAY! PRY! and pray again not to damage the case. You can try to use tape to cover the blade, but it didn't work well for me.
Once the bezel pops off a little you can use something blunt to pry it safely finally - I used the swiss knife bottle opener. I also opened a beer with it afterwards, but that's optional.

here's the watch with bezel removed:




Step 3.

Crystal removal. Once you get the bezel off the watch, you'll see a retainig ring that holds the crystal in place. Actually that's one part, but I guess you can push the crystal out of its frame.

Insert blade between the retaining ring and the case and pry:




It sits very tight, but use all your persuasion skills, and it will finally pop off.
In fact, you don't want it to pop off literally as it will send the dial and gaskets flying around your room (I tested that, so you don't have to). So be CAREFUL.
And try to SLOWLY pry the case open.

after you find all the gaskets you should see something like this:



the black gasket is made of rubber and goes around the dial on the 24hrs/GMT internal bezel, which is also removable.
The white one is plastic and holds crystal in place. SO DON'T LOOSE IT. No, seriously, don't.

here's a picture of all parts I disassembled:

 
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