Opening an Unopenable Caseback? ['72 Zenith Defy A3642]

[aac58]

I've had several watches with incredibly tight case backs. The glued nut and wrench has worked for me 100% of the times so far. I don't use a case holder when using the wrench as you can break it, instead I wrap it on a piece of fabric so I don't hurt my hand when holding it. Then I let the case back on pure acetone until the CA dissolves.

[dpn]

@aac58, thank you for your optimistic suggestion! From a lifetime of Games Workshop miniatures, I'm really comfortable working with superglue and acetone.

I don't know if I'm strong enough to grip the watch by hand like you suggest. I'll be giving it a try by hand before I buy a Bergeon 5078 or a Jaxa 5090. I'd hate to spend the money on a vice only to break it on its first use.

[watchweasol]

Have used the glued on nut method myself and had no problem getting the back off or removing the nut leaving the case mark free. Warming it up as mentioned before may just help to soften the deterioated gasket before removal making it a bit easier.

[rodabod]

If I were you, I'd probabl aim to take the back off myself and see if you can find someone reputable who can do it for less than half of what you were previously quoted. It's a conventional automatic, so shouldn't be tricky.

[Tudor]

I had a titanium case with titanium back (dumb) that galled and would NOT come off. Gasket was actually fine; Ti on Ti galls, and is as good as welded.

I got it off by using a can of "air" blower, inverted to release the super-cold fluid. This shrunk the back enough that the (correct) tool could get it free. Once it was off, I polished the threads on the back and case; applied Aerospace anti-gall compound and reassembled.

Moral of the story is: try freezing it off. A piece of dry ice will probably work.

 

But, my honest opinion, and what I'd personally do in your position (despite my three generations of tools for all sorts of stuff), is I'd send it back to Zenith in Switzerland for a restoration. Yes, it will cost more than an independent, but they will have the parts, tools and expertise to restore it properly. They'd probably enjoy it too. I saw how nice that original bracelet is from the back, and it deserves to be done right.

[dpn]

41 minutes ago, Tudor said:

Moral of the story is: try freezing it off. A piece of dry ice will probably work.

But, my honest opinion, and what I'd personally do in your position (despite my three generations of tools for all sorts of stuff), is I'd send it back to Zenith in Switzerland for a restoration. Yes, it will cost more than an independent, but they will have the parts, tools and expertise to restore it properly. They'd probably enjoy it too. I saw how nice that original bracelet is from the back, and it deserves to be done right.

I'll try the freezing, as well as heat, if the super-glued nut trick doesn't work immediately.

I've been quite tempted to send this watch to the Zenith factory in Le Locle. I just have a hard time swallowing the estimated $1,000-2,000 cost and 9 month time commitment for a factory repair.

I'm confident enough in my skills to pull the gasket gunk out, provided it hasn't flowed into the movement itself. I'll also be looking at whether I can *gently* pick off any crystal gasket gunk that is stuck onto the dial. Beyond that ... I'm sending this watch to someone good, not butchering it myself.

I should have the watch back in hand on Wednesday. Updates forthcoming.

Edited August 31, 2020 by dpn

[Tudor]

It’s a tough nut but for all the “common” high end watches, charging that much or more, it’s part of the game. 
 

Ive rebuilt a nasty old Omega 2500 for the practice but I’m not intending to pull my Planet Ocean apart myself. Just a weird thing because I have no such reservations about my 1680, which is worth considerably more. 
 

Worst case you have an uncommon original model in mint condition for $2600. Not bad in the grand scheme. 

[dpn]

@Tudor I take your point completely. I'm definitely not trying to cheap out on this watch. I *am* however, now obsessed with the idea of getting it open myself.

Here's the current status: I received the watch back from its service today. I could not see any signs of damage from their attempts to open it, which is good. I've glued a 1 1/8" nut onto its back. I centered the nut as best I could, and it's glued onto a very flat and smooth portion of the back. (I had tried to get a bigger nut, but this was the best I could do. I'm sure that, if this method will work, it will work with a 1 1/8" nut.)

The glue is curing for 24 hours, and at that point I'll be working to open it with a 1 1/8" wrench on a case vise that I've mounted in a bench vice. Hopefully the case vise will be ok, but if it's not I'll brace the watch with some wood on the bench vice. If my initial attempts are unsuccessful, I'll try careful heating at a single point with a soldering iron and/or the liquid from a can of Dust-Off to cool it down at a single point.

Fingers crossed, and I'll keep everyone updated! Thanks all for the encouragement and talking me down from a cliff of despair.

[dpn]

Well, that was so easy as to be anticlimactic.

I figured 30 minutes was enough curing for a glue I would be removing with acetone anyway, so I gave it a shot using my desktop jeweler's vise (cushioned by some soft plastic). I wouldn't have tried this without a case vice except that I noticed the design of the lugs gave two nice reinforced perpendicular surfaces that would fit easily into a jeweler's vice without significant risk of damage. Slow, even pressure with a 1 1/8" wrench opened the caseback on my first attempt. Easy peasy.

Thanks all for the advice!

Edited September 2, 2020 by dpn

[Rafael]

Awesome!

Nice job dude. I would send this picture to your previous watch guy.

Edited September 2, 2020 by Rafael

[dpn]

5 minutes ago, Rafael said:

Nice job dude. I would send this picture to your previous watch guy.

Already done. To be fair, I wouldn't expect a watch repair shop to have tried this method since it has a (small but non-zero) chance of damaging the case.

[JohnR725]

Now that the back is off you can clean up the gasket mass.

Now that the backs off we can see the watch I would probably drop the word vintage off for the description. Anytime you use the word vintage in watch repair the price goes up considerably. If there's fear of availability of parts the price will go up. So if you're just getting an automatic watch serviced the cost should drop by quite a bit.

[Rafael]

8 minutes ago, dpn said:

Already done. To be fair, I wouldn't expect a watch repair shop to have tried this method since it has a (small but non-zero) chance of damaging the case.

You're probably right if he had done it without your consent but he should have, at least, offer you the option. 

Edited September 2, 2020 by Rafael

[rodabod]

It should be straightforward for anyone working on it. I’ve found in the past that I’ve had to use acetone or petrol to dissolve the old gasket. I have a suspicion that gaskets dissolve like this when exposed to the wrong types of oils/greases. Which is why I always use actual silicone grease.  

[dpn]

Good points all.

After a quick dip in acetone, the nut popped off easily using pegwood.

The softened glue came right off using pegwood as well.

I'm currently cleaning the deteriorated rubber. It's coming off pretty easily, but there are some stubborn spots. Solution? More acetone and pegwood.

[jdm]

On 8/28/2020 at 6:39 AM, dpn said:

It's not that my question was against the rules of the forum, it's that it's out of place given the spirit of this forum. It would have been better placed in a watch enthusiast forum.

Sorry if I bring this up again. I understand your point of view however if we look to this forum composition it's mainly hobbyists of different levels with the precious help of few professionals. Many members don't repair and just like to hang out here. No special interests group, no taboo subjects, and everyone is welcome.

At some point anyone may need a third party recommendation and cost reality check, all good with me.

[dpn]

@jdm, thanks for confirming. Glad to hear that I didn't violate either the letter or the spirit of the rules.

 

[Tudor]

I sell a set of belts for Rega turntables with one each of six different compounds. 
 

anyway, my point is that I spoke with the manufacturers directly on best storage methods, shelf life etc. and most compounds are rated with a 15-year shelf life, though he did say with “proper storage”* they could last indefinitely. 
 

*Proper storage is an air-right and light tight bag. 
 

In the watch, the lubricant fumes may add to their demise but after 20 or more years they will be shot for sure. 

[Watchtime]

16 hours ago, dpn said:

Well, that was so easy as to be anticlimactic.

I figured 30 minutes was enough curing for a glue I would be removing with acetone anyway, so I gave it a shot using my desktop jeweler's vise (cushioned by some soft plastic). I wouldn't have tried this without a case vice except that I noticed the design of the lugs gave two nice reinforced perpendicular surfaces that would fit easily into a jeweler's vice without significant risk of damage. Slow, even pressure with a 1 1/8" wrench opened the caseback on my first attempt. Easy peasy.

Thanks all for the advice!

nice job, happy it "turned" out ok...:) as for a full service on a manual movement,  a watchmaker friend of mine charges around 200 euro/ 235 dollar with warranty so $650 sounds ridiculous....

But I know from experience that sending a Seamaster Chrono to Omega is also expensive but it was completely overhauled with new stem and crown, gaskets, new crystal, new pushpins, serviced, waterproofed and regulated.

[jdm]

53 minutes ago, Watchtime said:

But I know from experience that sending a Seamaster Chrono to Omega is also expensive but it was completely overhauled with new stem and crown, gaskets, new crystal, new pushpins, .

I hope that replaced parts are returned to the owner, demanding collectors may be willing to pay dearly but they become very unsettled by loss of total originality when even slightly different, "service parts" are fitted.

[dpn]

@jdm You're not joking -- my father insists on sending his ~1978 Rolex GMT Master to Rolex for service. He absolutely will not compromise on this, even though I think that he's paying twice or three times what he would pay if he sent the watch to a competent independent repairman. Not only is their service really expensive, but the last time he had his Ref. 1675 GMT Master serviced they replaced his nicely-faded blue and red bezel insert with a new one. He hates how the new one looks, and I think that replacing the original bezel insert probably diminished the watch's value by $1,000 - $2,000. Of course, Rolex wouldn't return the faded bezel insert it replaced. Seeing that faded GMT Master bezel inserts sell for up to $2,000 each, I suspect that his bezel insert wasn't destroyed, but was put on the secondary market by the repair person.

If anyone is curious about the disposition of my (formerly unopenable) Zenith Defy, I used the NAWCC business directory to call a couple of repair people. My first choice just had his entire shop in downtown Sacramento destroyed by looters during the recent unrest, so he's out of business. That's a real shame.

I connected with another watch repairman from southern California. We had a nice talk on the phone and my Zenith Defy and another vintage watch I own are both on the way down to his shop. He quoted $385 plus parts for a normal automatic movement overhaul (no complications other than a date) and two-three weeks for service. He said that he's normally really backed up, with a 12-week turnaround time, because he handles many repairs for some of the larger jewelry companies in the region. As the jewelry stores' business has dried up because of COVID-19, he's actually short of work now. This works out well for me, and I'm glad to be able to send him a couple of watches to work on.

The original repair shop, incidentally, would *really* like to work on the Zenith Defy. I'm going to pass.

I have asked them to explain what they meant by "boiling the watch" to get the caseback off. My gut is that what they were trying to do was poorly described to me; I suspect they meant "gently heat the caseback" with boiling water or steam to try to get the disintegrated gasket to loosen up.

 

Edited September 3, 2020 by dpn

[JohnR725]

7 hours ago, jdm said:

I hope that replaced parts are returned to the owner, demanding collectors may be willing to pay dearly but they become very unsettled by loss of total originality when even slightly different, "service parts" are fitted.

I have a friend who has an Omega coaxial and he was looking for where to service it. So basically I had recommendations of private shops but Seattle has an Omega Swatch group service center. I figured that would be the best so he took his Omega down when they had a boutique. The boutique is missing now the rioters destroyed it. Apparently the service center is going to relocate somewhere else nearby. So when they finished the watch they sent it back and included a complementary box to put the watch in and they returned all of the original parts. some more have the photograph that he emailed me and you could see mainspring barrel with the spring out coaxial parts and he wanted a new dial is very happy with the dial.

But Rolex has ideas for their watches very very set ID's. When you purchase a Rolex watch it be much better if they would acknowledge your only leasing the watch because it's not really your watch it's their watch. That's why we get it serviced they restore it back to do because it's really their watch. Things like faded dials and imperfections that usually have a interesting effect on the price of making the watch much more valuable is not the way Rolex sees this. Which is really sad for the consumer.

50 minutes ago, dpn said:

He quoted $385 plus parts for a normal automatic movement overhaul (no complications other than a date) and two-three weeks for service.

that actually sounds like a decent price. It's probably a West Coast price because I had asked where I work and that's approximately the price except when I mentioned the word vintage I believe $75 would've been added on to the price. That is why in my message up above I suggested removing the word vintage for the conversation. Then your service time is good because a lot of the shops got backed up there all sorts of interesting parts challenges and some of the suppliers are still shut down even some of the distributors of the watches are currently shut down or not functioning at capacity which is representing issues for getting parts.

[rodabod]

I bet some buyers end up spending more on servicing costs that the original outlay for the new watch in the first place. That doesn’t really make sense to me. 

[dpn]

@rodabod I was very nearly in that situation myself. It's an easy mistake to make for a naive vintage watch collector. Modern top brands are so expensive, but reasonable looking watches from those same brands in the 60s are inexpensive and readily available. 

This is also the case with one of my other loves -- vintage camera equipment.

[rodabod]

I’m also into vintage camera equipment but stick to just two cameras these days - an Olympus OM4 and a FED 2 which is a Leica rangefinder copy. Wouldn’t fancy doing camera repair!