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Discussion Starter · #1 ·
I'm trying to restore a 7A28-7029 watch. I have found the part number for the case gasket, but am trying to find either the part numbers for the o-rings and crown seal or the specific dimensions of the o-ring and crown seal. And yes I could measure the existing o-rings/seal, I have no clue if they are the original part or if they are the original part if they have shrunken or expanded over time and I'm trying to put it back together as it was from the factory. I know it has been opened in the past as the gasket on case back was missing when I got the watch which is another reason I don't trust the existing rings and seals as being correct.

Thanks to anyone that can help.
 

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watching with interest.
 

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Adrian at VTA sells a kit with all the seals. I bought mine from him on eBay. My 7a28-7039 passed a pressure test with those seals installed.
 

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and Cognoscente ... 15J Quartz Chrono's
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You may find this recent thread in the Watchmaking and Tinkering section helpful.

Unless you want to be secure in the knowledge that you've used genuine Seiko seals (p/n EG0060B0) or are planning going swimming with the watch once you've restored it, I'd personally recommend using Cousin's generic mini O-Rings, p/n G39081. $2 for a pack of 10 (compared to £6.95 each). :)

477915
 

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what about a crystal - is there a source for original or good AM crystals?
 

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and Cognoscente ... 15J Quartz Chrono's
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For that particular model - 7A28-7029 ? I don't do 7A28's (only 7A38's), but the 7A28-702x case is very similar to that used on the 7A38-706x range and they all share the same crystal, Seiko p/n 320W40GN00. These are 32.0mm Ø x approx 1.6mm thick, with a small polished decorative beveled edge. Closest AM crystal I've found (and used a few times myself) is Sternkreuz p/n XMF320.927.
 

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Ah - now I see the reason for your question, Mike. ;)
Assuming the watch is in condition described, new seals and a crystal are in order. Actually, already sourced a crystal.

I remember seeing these watches back in the early 80s in the department stores right after I got out of college ... they were SOOOOOO out of reach cost-wise. These and the moon phase versions. Been wanting to have a nice example for quite some time but 7A28s are becoming out of reach cost-wise as well.
 

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Discussion Starter · #9 ·
what about a crystal - is there a source for original or good AM crystals?
Fortunately the crystal is in perfect shape. Just ran across the watch in an estate sale but that appear to have never been worn... which is good because if they had worn it without any gasket on the case back I'm pretty sure it would have gotten moisture inside the case and really screwed things up.
 
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