Hi Everyone, Please excuse me if I'm posting in the wrong place. I'm new to this forum and I'm hoping being an Omega forum I might find someone who can advise me. I came across an Omega Dynamic about six months ago and since then I've been hooked, more recently on hummers. I’ve started doing repair jobs myself and I’m learning as I go, my tools collection is growing too. I've got an Omega Seamaster F300 that I'm doing a few simple cosmetic jobs on to restore it as much as I can. The case number is 198.0056.170. I'm replacing the crystal as it has a deep scratch and I've managed to separate it from the case. I don't seem to be able to find a definitive answer on the measurements. My (cheap) calipers say 31.1 x 2mm but I have a feeling it is more like 31mm x 2mm. I saw one for sale on eBay that states a 31mm diameter. Does anyone else know for sure as I want to get it right when I order form Cousins, so I can pay £0.65 instead of £30? I also noticed some muck around the stem which I'm guessing is the remains of a 40 years old gasket, see the back picture. I would like to replace this but it seems to be inside the case edge. I'm not sure how to remove the back or front bezel rings (see pictures), so I can replace the winding stem gasket. I tried pulling up from the bottom but I don't want to force or damage anything. Any ideas on this? Better still, does anyone have a service manual for this or a similar Omega? I asked Google but could not find anything useful. I’ve got a manual for the 1250 movement but this does not help me with the case. I want to replace the Crystal on a 198.0056, 198.0039 and a 198.0044. I also want to replace the winding stem seals, the rear case gaskets are in good shape. Annoyingly Cousins don't seem to have the specific documents pertaining to the case numbers I own and want to replace the crystal on, but they have other 198.XXX models. The ones I own all measure 31mm across but looking at similar omega 198.XXX cases it seems their thickness may vary. I was hoping to do a parts order, to make the postage worthwhile, without taking them all apart, and risk losing pieces. Any advice greatly appreciated. Many thanks. Richard.
I am sure the crystal is a sapphire crystal . So replacing it with a mineral from ebay is not so good . Even if it''s cheaper . Have you looked on http://www.boley.de/en/case-parts/omega?page=1 for the reference . There you can see what kind of gasket you need . You will need a new gasket for the crystal also . Hope you have been taking the movement out in one piece . Otherwise you maybe toast . http://www.boley.de/en/case-parts/omega?x=0&y=0&search=198.0056
Sorry it was mineral . https://www.cousinsuk.com/search?SearchTerm=063TN5190 .Could the crown gasket sit in a groove in the pendant tube . Have replace that on one of my F300 . Clean it and replace it . A little tricky but could be done from the outside .
Hi Richard and welcome. The gasket is inside the crown. There's nothing in the case tube. So you have to replace the crown as it's virtually impossible to get the old gasket out and a new one in. On the one you have a picture of, the inner case is pressed in from the bottom. A gasket in a groove makes sure it doesn't pop out. If you want to separate the two, just press it out from the dial side. The old gasket is probably turned into tar by now, so it might stick pretty good. You probably need a press to get it in again. The same with the 198.0044. Like this: You can get generic glass from Cousins if you measure it accurately (get better calipers), but it's better to use original Omega.
Crystal - 063TN5190 - GLASS MINERAL D31 H2 Crown - 069SX43242 - CROWN PLATED PVD YELLOW 2N Seal - 088NS5081 - SEAL O-RING D30 D31.6 Seal - 088NS5085 - SEAL O-RING D32 D33.6 Crystal gasket - 098ZT0006 - L CRYSTAL GASKETS D32 T1.1 H3.2 Case tube if needed - 090ST0090 And yet more evidence that Cousins are just soaking the crap out of their customers if they are charging 30 UKP for the original Omega mineral crystal. That is over 2.5 times the cost from Omega...holy mark-up batman! They are certainly trying to make all they can before the cut-off!! Anyway, hope this helps. Cheers, Al
Thanks everyone. Rogart: Yes I thought it was sapphire too but I was advised otherwise. I even bought myself a cheap diamond tester, tried it on my colleagues Rolex, and my crystal is definitely mineral. Ketiljo: Once again, thanks for the advice. I'm glad I didn't try pulling it from the bottom. It was really useful seeing your Titus like that, I have a better understanding how they fit together now. Incidentally, have you ever measured the crystal on your Titus, is 2mm thick? I have the same watch but with a silver dial. Archer: Thanks for digging those part numbers out. The £30 was the eBay price, I believe Cousins was a heavily discounted £25. I was hoping to be able to use generic parts, which is why I am trying to find dimension specifications. As Rogart mentioned many of us don't have the ability to buy original parts at sensible prices. I wondered what you meant by "cut off" so I googled it. This is terrible news. So for those of us that collect old Omega's where does this leave us?
Now you have the dimensions, so you can use a genuine mineral glass or a generic. In this case it's not a special shape or an in between size, so generic would work just fine. It's just a disk of glass after all, so nothing special about an Omega one... Cheers, Al