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Remove old screw down crown seal

familyguy

By familyguy
in Watch Repairs Help & Advice

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familyguy Member

familyguy

Posted
Posted (edited)

I have a dive watch I purchased new, in the early 1970's with ETA auto wind movement, It's looking a bit sad and I would like to get serviced and looking nice again, it is I hope a good candidate as it was only ever serviced by a watchmaker, recently I tried to unscrew the crown, it was very stiff, when it came undone I noticed a black goo around the crown tube, looks as if the seal/o-ring has disintegrated, my question is how to get the goo out of the crown thread, is there a solvent I can soak it in. I did once have a winchester of benzene but was forced to get rid of it on pain of divorce - I'm sure benzene would have done it.

Edited by familyguy
Correct a typo
  • familyguy changed the title to Remove old screw down crown seal
watchweasol Distinguished Member

watchweasol

Posted
Posted

Hi Ditto  old Hippy, having got a new crown then experiment removing the old goo the experience will come in handy for the future,   IPA, Ronsonol, benzine will probably do the trick, finding the correct cleaner will be handy as case back gaskets also get in this state.

familyguy Member

familyguy

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Here are pics of the offending parts, movement is an ETA 2783, this is the first time I have removed the stem/crown and I notice that the square section of the stem has a twist in it - is this normal ? I'm assuming it is, as the watch was only ever serviced by a watchmaker and I doubt the stem could transmit enough force to twist the square section, I feel the the stem would break at the thread - the thinnest part.

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jdm Distinguished Member

jdm

Posted
Posted
On 12/12/2020 at 4:39 AM, familyguy said:

I did once have a winchester of benzene but was forced to get rid of it on pain of divorce - I'm sure benzene would have done it.

I think you may have had benzine (motor petrol, gasoline) not benzene, the confusion is common among English speakers. Anyway the cleaning agent is not important because to replace the gasket in the crown you have to lift the top washer anyway, as said that's a bit of fiddly work but certainly doable. Or fit a new crown.

 

11 hours ago, familyguy said:

I notice that the square section of the stem has a twist in it - is this normal?

Yes it is, for period of time ETA was making movements with a twisted stem, probably with the idea these would help the clutch wheel pressing, then fortunately they stopped.

 

11 hours ago, rodabod said:

I reckon you may be able to get a matching replacement from cousins if you are based in Europe. 

Even if you're not, Cousins UK ships worldwide for the actual Royal Mail cost.

oldhippy Distinguished Member

oldhippy

Posted
Posted
32 minutes ago, watchweasol said:

Somewhere in the recesses of my mind  I seem to recall that the stem is correct with the twist but will have to dig deeper. 

That stem is correct it is to help it to engage. 

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Nucejoe Distinguished Member

Nucejoe

Posted
Posted

Correct stem.

Soak in diesel fuel or boil the stem/crown in boiling water for 10 min.

The seal was originally molded by heat, 250-400 degree C  steam.

 

 

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