My circa 1982 Seamaster chrono has dried up pusher and crown seals. My local watch repairman states that replacing them is no easy task. He mentioned having to put the case on some kind of lathe to do the crown seal replacement, I believe. He made it sound like the amount of labor involved would make this cost prohibitive. Has anyone had this job done or had any experience with this?

Thank you.

 

I routinely disassemble the pushers, remove the old o'rings, clean the pushers and tubes, then install and lubricate new o'rings, it's part of my normal servicing procedure.

Crowns can be a bit more difficult, because the o'rings in them are difficult to source, but with the proper o'ring the crown one can be easily replaced as well. If that's not an option, a new crown is required.

I have never needed to use a lathe to remove an o'ring, as for cost prohibitive, it's not, otherwise I would not include it as part of a normal service fee.

You should look for another watchmaker.

Rob

 

Damn, I was going to make that joke!

 

Actually, it's the crown that he says would have to be put on a lathe, not the case. I've seen a photo of the inside of the crown and it does indeed look very hard to access the seal. There's little space to remove the seal and if it's dried hard that makes it more problematic. Omega would replace the crown with a different version instead of trying to replace the seal. Mine's like new so I'd like to keep it.

 

O-rings could be removed with acetone or thinner. Solved them over night and you end up with a black liquid . That is the easy bit . Finding the right O-ring is harder.
Inside diameter is as the crown tube or slightly smaller . But how large is the outside or the thickness of the o-rings?

 

Haven't tried this on an Omega but it's a good trick?
https://adventuresinamateurwatchfet...eiko-6105-and-62mas-crown-gasket-replacement/

 

Thanks for sharing. It is now bookmarked.

 

Omega seals aren't as cute a Zenith seals.

 

Great info, thank you. I'm pretty sure this is the same crown design and problem with my Seamaster. Horlogerie, I appreciate your post as well. And you routinely replace the gaskets in these types of crowns?

 

I think Horlogerie is thinking of a different crown design. This one has a steel washer that leaves a space not only too small to get the hardened o-ring out (like the Seiko crown shown in the link), but also too small to get a new o-ring in properly without damaging it. Perhaps I could remove the ring by dissolving it and reinstall the crown without one. I'm not concerned about waterproofness.

 

That Zenith seal would make a nice coat.

 

Yes indeed there are many designs that don't lend themselves to replacement of the o'rings.

In those cases, a new crown is the only solution.

Not having an o'ring or sealed case is a problem, not so much for waterproofness, but for the fact that is the case is not hermetically sealed it will allow moisture and dirt to enter the case and cause damage.

When you put on the watch, the case heats up, and so does the air which expands, if there is an opening it will vent. Once you take the warm watch off your wrist and put it down for the night, as the case and air inside cools down, it will contract and if there is a case opening, it will suck in the surrouding air, moisture and dirt, eventually causing damage to the movement.

So no matter what, your case needs to be sealed to protect the insides from the outside elements.

Rob

 

good anwers, but O rings and O ring lubricator is a vast topic. as far a using a lathe, I wounder. a lathe IS USED to machine a proper grouve for the proper O ring.

 

Alright, that seals it. Thank you!

 

That was an interesting method to remove the washer in that link. As you can see, the washer that holds the seal in is the difficulty with replacing the seals on most crowns of this type. In production I believe the washer is swaged in place and it's unclear if the method used in that link would ensure that the washer stayed in place over time, but that would make the job much easier to do than using a lathe if it holds up. I have been communicating with Lancaster about what his watchmaker proposed even before he started this thread, and my guess is that he was going to use the lathe to cut out the old washer, and possibly to burnish a new washer in after replacing the seal. This is the way I have seen others do this job before.

It's a task that takes time to do properly...

Cheers, Al

 

yes: using a lathe to remove a swaged or "press fit part" will often cause less damage than prying it out.

 

Here's a photo of a similar crown. It's pretty clear that a hardened seal would be difficult to remove from the space inside the washer. And I can see where it may be impossible to insert a new one without damaging it.

I'll assume the old seal can be removed by dissolving. To facilitate inserting a new seal it seems possible to me that a fine grinding tool could be carefully inserted into the space to grind off some of the inside of the washer all the way around the perimeter.

Does the washer have to be this wide to have enough washer to retain a new seal within for the crown and seal to be viable? It seems it might be possible that a somewhat thinner washer will suffice .

 

the washer needs to be removed. cheaper to buy a new crown.