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Craftsman
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Discussion Starter · #1 · (Edited)
I have read a number of posts on the web from a select few watchmakers who have rebuilt 6105 diver crowns. As you know, these crowns are sealed and were never meant to be serviced. The preferred method for opening these crowns is to compress rubber o-rings down into the crown after the stem is removed. Continuing to force these o-rings down into the crown creates enough internal pressure (similar to hydraulic pressure) to force the steel retaining ring up and out of the crown groove allowing the crown to be opened. The hardened rubber o-ring seal can then be removed and a new o-ring seal installed.

The second part of this operation is to reform the steel retaining washer that seals the crown using a staking set and then reinstall the retaining washer into the crown groove and flatten it out to form a permanent seal.

I read a recent post from one of our resident experts, Sir Alan, on a 6105 crown rebuild he did and decided to attempt this repair myself using my own 6105-8110 diver as the test case. I had theorized for some time that a Seitz jewel press and the right pusher bit could be used to force the washers into the crown if only the right pusher were available. With this in mind, I reached out to Simon, Sir Alan, with my idea and he set about crafting a pusher I could use in my Seitz press to force the o-rings down into the crown cavity. I am just blown away by Simon's abilities with his lathe and after a few attempts he managed to craft a couple of pushers that would work in a Seitz press specifically for this job.

I received this special pusher from Simon several months ago but just got around to working with it today as temps here in VA are in the mid 90 degree F range and just too hot outside to do anything. A good day to work inside. The good news is the Seitz pusher method worked beautifully.

Below are the pictures of my 6105 crown rebuild. This is a fiddly job but I am very pleased with the overall outcome and how well the Seitz pusher Simon made for me worked in opening up the sealed 6105 crown. He even went so far as to heat treat and blue the steel pusher he turned in his lathe for me. Thank you Simon.


Step 1: Remove the crown from the stem. A pin vice and bit of heat on the crown helps here.

Step 2: Force rubber o-rings into the crown opening to force the steel retaining ring up and away from the crown retaining edge. I had to use ~ 23 o-rings to get the retaining ring to separate from the crown. It could then be lifted at the edge using one of my small screw drivers. I sourced the small o-rings from Cousins in the UK.



Step 3: Remove all compressed o-rings and the old crown seal. I believe there is another small metal spacer that sits in the bottom of the crown but this spacer did not want to come out so I left it in place.

Step 4: Clean the crown and retaining washer and prepare to install the new o-ring crown seal.

Step 5: Reform the steel retaining washer into a uniform cone shape for reinstallation into the crown using a staking setup. I used a cup type stump and centered the washer in the bottom concave side down using my centering stake and then flipped the centering stake over and used the ball shaped end to form the washer into the concave shape needed for reinstallation into the crown retaining groove.


Step 6: Install new greased o-ring crown seal and place the steel retaining washer on top domed side up. The edges of the retaining washer must fit uniformly around the crown edge. I used an small blade to clean up any rough edges on the retaining lip of the crown before trying to re-fit the retaining washer. Using the appropriate stake gently tap on the center of the retaining washer until it seats in the crown groove and flatten the washer down to a flat disk shape washer to keep it in place. Crown rebuild completed.


Step 7: Clean crown and stem threads and reinstall crown on stem using blue thread locker. Allow thread locker to cure overnight and reinstall into movement. Job complete.

 

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Craftsman
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526 Posts
I'm really glad the pusher worked John - I enjoyed making them and experimenting with blueing the steel. Luckily I made two (identical) so I have one to use when I next get a crown that needs a rebuild. I can also use it as a template if I make any more. :)



Can you confirm if you removed the old gasket from the crown before pressing the small gaskets in. I found I had to when pressing with my thumb (and it took ages to pick the hardened rubber out) but it might be that with a tool to press with that this isn't necessary.
 

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Special Member
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Thank you John (and Simon) for this really informative post. Great result!


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Craftsman
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Discussion Starter · #7 ·
Hi Simon. No, I did not have to remove the old gasket in the crown before pressing in the o-rings. I recall your note about having to do that on your crown rebuild. It all seemed to go very well for me. Removing all the pressed in o-rings and the old hardened seal was not too bad but the very last o-ring down in the bottom of the crown was a bit tough. Finally resorted to a needle and managed to remove the final o-ring. I could not get the steel spacer out of the bottom of the crown so I just left well enough alone.
 
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