Hello
I orded a new tachy crystal for a speedmaster mark II 145.014 . I did think that i would get a new gasket or gaskets with the new crystal .But no sir . Order was from https://www.cousinsuk.com/ . My question is where can i find a new gasket . And what partnumber does it have ? . Is it one o two gaskets . Their was only one on when i bought the case . Ya only bought the case not a whole watch

 

You need two gaskets. The one that fits around the crystal itself is 35mm i.d x 0.8mm dia. The one that fits around the outer edge of the inner bezel is one of those non-standard sizes that you can only get from Omega (I don't remember the size)

 

Ok . That is an o-ring ? If so i have got that . It didn't say what kind of o-ring it was . I orded that and a lot of other parts . Their where 2 o-ring stated on the 145.014 case . Bought both . But the other on i don't have . Can i look at http://boley.de/en/ maybe .

 

I see 3 O-rings listed on the Extranet:

Crystal gasket - 088NS5091 - SEAL O-RING D35 D36.6 Ø0.8

Case back gasket - 088NS5139 - SEAL O-RING D34 D36 Ø1

Unidentified gasket - 088NS0802 - SEAL O-RING D31 D32.6 Ø0.8

Hope this helps.

Cheers, Al

 

The first and the second i have got . Orded from cousinsuk . The last one i haven't . But according to http://boley.de/en/case-parts/omega/1659?page=19 it should be a crystal gasket . 802 glasdichtung .That is crystal gasket . 088-5091 is gasket under crystal .Shall see if i could get it from Cousinsuk . Searching by the reference number
Thanks Archer .

 

088NS5091 is the one I used when replacing the crystal on my 145.014

I'm not sure about the 088NS0802 though, did some MKII's come with an o-ring under the crystal?

 

If you search 088NS5091 with CousinsUK you will find it in stock and at about GBP10 (+tax).
Good Luck!

 

Wonder that to ? The 088NS5091 i have got . I can order the 088NS0802 from Cousinsuk .But do i really need it ?

 

If it is the one I am thinking about, it stops you crushing the edge of the crystal against the inner bezel.

 

Could be .Have to check the dimension of the bezel . Because i haven't disassambled the watch and hasn't worked on a mark II before .It 's new to me . I think that my watchmaker would have to do it . But i would like to have the parts ready . I don't think he has them in the store .

 

I know this is an older post , but I hope my experience can assist anyone else that attempts to change a crystal on their Omega Mark II.

I just changed the crystal on a Mark II I acquired recently . It ordered an original crystal and It came with Crystal gasket - 088NS5091 - SEAL O-RING D35 D36.6 Ø0.8 . After reading this post I used my press to push out the crystal from the case careful to notice the order of any gaskets, chapter rings , or other parts that may be stacked in there . So far , so good .
The crystal came out and under it there was one gasket in good shape that fit the perimeter of the case on top of the chapter ring . The gasket is a cushion between the chapter ring and the glass crystal . I did not find any other gaskets and I was scratching my head as to fewer gaskets than had been mentioned in this post , and as to how the crystal was supposed to stay in the case . I noticed that the crystal looked thick on the edge and sticky with what I thought at first was black adhesive .
After looking at the new crystal I noticed a groove around the edge where the gasket that came with it fit . I repeatedly tried to press the gasket and crystal into the case and every time , a large section of the rubber gasket was squeezed out . I knew I would not have too many chances to use this gasket if that kept happening . I tried using my thumb to press the gasket into the groove and tried again....I did use a bit of silicone in my attempts to assist in the process . I thought I had it this time , but at the very end of the press in , a part of the gasket came out again .

I checked my stash of parts and at some time I had bought some o-rings from Esslinger and I found one that was a the same circumference , but a hair thinner . I tried again and I thought I had the crystal in , but again at the end of the press in , a tiny bit of the gasket came out and was caught between the crystal and case . I used some firm thumb pressure to push the crystal out a tiny bit . and the bit of the gasket slid into the groove thanks to the silicone and I was able to press the crystal firmly in ,...finally .
The sticky stuff on the edge of the crystal was the old rubber gasket and the rest of it was smeared in the case . The case back gasket was also not an O-ring any more , but a sticky glob where it was seated in the case . Real rubber I guess .

I hope this is a help to anyone changing their Mark II crystal .

 

If I recall that crystal uses a rubber o ring that fits in a groove around the crystal. The crystal with installed o ring are then inserted into a special tool that compresses the o ring. After the crystal is pressed into the compressing tool you center the crystal in the correct position and push it out of the compressing tool and into the case. You get it perfect about 60% of the time. I have the tool at my shop and will take pictures of it along with the omega part number if anyone is interested. There is a generic version of the tool available but of course it is not as precise as the Omega version.

 

Thanks for the post . It makes sense now . The crystal alone will drop into the case , but very close tolerance with the rubber in the crystal groove .

 

Pictures...

















Using a smaller O-ring is not the correct solution, but using the proper tools will make the job go very easy. Several people on this forum have made their own home made versions of the Omega crystal fitting ring that I show above, and have had good success with them. Success rate should be way more than 60% if you use the tools correctly.

Cheers, Al

 

This is very interesting and educational.

https://omegaforums.net/threads/mk-ii-speedy-project.16554/page-2#post-180465

 

" Using a smaller O-ring is not the correct solution, but using the proper tools will make the job go very easy."...
I can't argue with that .....Where can I get the proper tool for the crystal .

 

Where have you looked so far?

 

To be honest , I just acquired the new crystal and watch from 2 Ebay sellers on Friday and Saturday and did the attempts and install on Sunday ,....before I came across this most informative and interesting this post . I am very fortunate that I did not damage the crystal which cost me $105.00 with postage .
If I come across the tool or make one using Stewart's instructions I will remove the crystal and use the proper O-ring .

If anyone knows where I can get the tool I would appreciate any information , and a big Thank You to both Archer and Stewart for their input and expertise in this post .

 

I would suggest looking on eBay for the tools - they pop up there from time to time.

 

With 3-d printer so popular this days? Someone would make some tools and sell? I look from time to time on Ebay but i haven't seen one for ages?