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Omega 861 Speedmaster Mark II


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Hello All;

On my desk landed a 1975 Omega Speedmaster professional Mark II. It was in a sorry state and water ingress was suspected. The last services were quite a few years ago, mid '80's towards the '90's. Those services were performed by a watchmaker working for a local highly reputable jeweler with a glossy facade. Instead of using the proper tools (a guide-ring) to replace the glass, for ease or necessity the official seal-ring was taken out and the glass was placed using a black sealing-kit. The back-cover received the same treatment, instead of the correct O-ring, the O-ring groove was filled with the same black sealing kit and the cover was thereafter closed.

By a stroke of luck, the Omega was replaced by another watch and has for 20+ years been stored in a drawer; until recently. The owners current watch was sent away for a service and the Omega had to fill the gap. Unfortunately the Omega came in contact with water. The owner suspected water ingress and as soon as his current watch was back from servicing, the Omega was sent to me.

Though time, the black sealing kit has eaten away the printed Tachograph-ring and made its way onto the edge of the dial.

The task on hand; a full service of the movement, installation of a new mineral glass and replacing all seals. Perhaps some new luster to the watch-case........

Whether I show the full restoration of the watch-case needs to be seen, but I like to start off with a walk-through of the 861 movement.

Two Omega 861 manuals were of enormous help;

Omega 861 service manual.pdf

Omega 861.pdf

I printed them out and best is to read and cross reference both manuals before starting. Each manual contains important information, not necessarily mentioned in the other manual ! Once the information is combined, then there is enough information to do a proper service.

For chronographs like this one, I replace each screw after the component has been removed. This avoids screw mix-ups, but can cause some problems too ...... read installing the pallet-fork bridge.

Without any further ado;

Here is the watch as I received it;

861-01.thumb.jpg.e2525c7ddd5bfa47b854fa5a79426938.jpg

Luckily the inside looked pretty okay and no visual signs of water. BTW, the black sealing kit on the back was already replace by a proper O-ring.

861-02.jpg.1519c420fa7a74278a86cf19da002a92.jpg

Took some Watch-O-Scope shots (lift angle 50 degrees)

Dial up:

5957d66a2ed2e_OmegaBeforeDU.PNG.bfaf31178052a0c400a59467423f25d8.PNG

Dial down;

5957d669290d3_OmegaBeforeDD.PNG.32caecffa3d256ee8f09f15d032b07ac.PNG

Crown Up;

5957d668414bd_OmegaBeforeCU.PNG.c283ca3f64b5dc6b6044ea8abb42bafd.PNG

Crown down, this one was harder to get due to a weak signal;

5957d6675ccdd_OmegaBeforeCD.PNG.d373413926bf5eff6f1a0486787c91aa.PNG

All in all, not too bad.......... at least not "devastating" differences in the four positions.

The movement is attached to the case with two clamps and a spacer ring. Remove those plus the winding stem and the movement can be taken out. Clearly visible is the black sealing-kit around the dial edges, starting from 5 till 10-o-clock.

Pay special attention when removing the little hands, these have different tube sizes. I stored them separately, each in their own container; Left, Bottom and Right.

861-04.thumb.jpg.33bd916e9c8ec7afe280696616c63297.jpg

Taking ample pictures was a great help to me as well. I had to consult them a few times during the assembly. Another remark I like to make is that the movement doesn't sit comfortable in an universal movement-holder. The movement-holder I used was a Bergeon 4040 and with great care it can be done, but later I've spotted on eBay Omega 861 movement holders for reasonable prices .....

On the picture below, the Joke 1774 has been removed. This exposes and give access to the click (see arrow). The main-spring can now be disarmed.

861-05.jpg.60f44968341bbbcd5bb44687ce980343.jpg

Next is the hammer-spring 1734; it sits on two center-pins and has to be lifted at its heel. The hammer 1728 sits on a post and can be lifted straight off. Remove coupling spring 1731 and coupling yoke 1724. Be aware of the eccentric screw, it clearly has a different shape. I left the unit (wheel bridge 1716 and coupling wheel 1712) in one piece. Later I dismantled the unit and attention has to be paid which way around the coupling wheel is mounted.

861-06.jpg.4e50eba529b47f0dea986531794835d6.jpg

Removed the plastic blocking lever 1726 and blocking lever spring 1733: in the manuals different names and number are used for seemingly the same item. One end of the spring has a "hook". This "hook" has to face upwards against the blocking lever. Next to remove is the cam-jumper 1845.

861-07.jpg.0e24e5b9a644cf9bdb54bbe367a5b3f1.jpg

Next is the chronograph bridge 1037. The manuals are not very clear if one does this for the first time. Underneath and fixed to the bridge is a thin spring for the minute recording jumper. This spring will come together with the chronograph bridge. The spring pushes against the minute recording jumper 1767, which is attached to a post underneath the bridge. While lifting the chronograph bridge, the jumper 1767 may, or may not come as well. I my case, all lifted in one piece. By turning the bridge around, it all becomes clear .... Das "Aha Erlebnis" ;-)

861-08.jpg.95bfc51dd6a8ccbbd45d346a2405425b.jpg

Remove chronograph runner 1705, minute recording runner 1708 and intermediate wheel for minute recording runner (1714); note which way around of the wheel !

861-09.jpg.98cb8d25371fde7e31709a32ee3117f8.jpg

Remove operating lever 1841, operating lever-spring 1842 and connecting lever 1840. Attention: The operating lever 1841 sits under tension. After I removed the screw and attempted to lift the lever 1841, the connecting lever 1840 had its personal launch ...... luckily not that far ......

861-10.jpg.ea4c392fc161372d72af7dc701a408f2.jpg

Remove operating lever 1720. In my case, the "Glossy Facade Watchmaker" left a surprise; the top screw was sheared off right under the screw-head and screwed in by literally one thread (red arrow, picture above). I later attempted the remove the remaining stud, but no success. After consulting the owner and this being the second, more a guiding screw, the decision was taken to repeat the GFW-trick. The screw held for many years, so hopes are it will do it again.

Remove (and note position) upper cam for hammer 1844, remove lower cam for coupling clutch 1843, remove stem for "Zero pusher" by undoing the screw, remove bolt-spring 1752 and bolt 1759. Carefully, use Rodeco, remove fragile friction spring for chronograph runner 1735. Carefully remove the driving wheel 1710; I managed to lift it using two hand-levers.

861-11.jpg.cec847eafa4e2cec4ec9f3b733d71218.jpg

I then removed the balance & bridge, the pallet fork-bridge & pallet and the escape wheel bridge & escape wheel.

Flip the movement over;

861-12.jpg.f3c1044e5a526b75734d4128f0cddc54.jpg

Remove bracket for operating lever 1784 (note position), remove hour hammer spring 1794 (not described in both manuals, note how it engages) and remove hour recorder stop lever 1750. Be aware: as soon as lever 1750 is lifted, spring for stop lever 1793 will jump free !!

861-13.jpg.ea3f2c8229707cfe9881d8fe83eedb43.jpg

Remove spring for stop lever 1793, remove switch mounted 1779. Watch out !! Little screw at tail end is an eccentric (see arrow above) ...... do not touch !!

861-14.jpg.bee70c6a3d6c4d63db92ae6b79db06b7.jpg

Remove hour recorder bridge 1775;

861-15.thumb.jpg.30ad822de08a176749ebbb93b6cd6c39.jpg

Remove hour hammer 1783, hour recorder runner 1788.

861-16.thumb.jpg.9ccf203795071242ea7a29f9c8911da2.jpg

Next is, according to the manual, removal of the friction spring for driving pinion 1792 and driving pinion 1791. I did this according to the manual, but found out that the removal of the friction spring 1792 and driving pinion 1791 can be done (much easier) later when the main-spring barrel is removed. Remove support bridge for dial 1776.

861-17.jpg.b883d0d4338a354d5978271b28796761.jpg

Remove hour wheel and keyless works, note the two intermediate wheels. Remove canon-pinion.

861-18.thumb.jpg.533cb2643f384d52d4049e051391b829.jpg

Flip movement over;

861-19a.jpg.eca8f60ab561cdbc7e64d5202e7b13f3.jpg

Remove barrel bridge. Note crown wheel and click are underneath barrel bridge. Also note that ratchet wheel lays on top of the barrel.

861-19b.thumb.jpg.3ffc8582e8321ceab5bba3237eac40ab.jpg

Remove wheel train;

861-20.jpg.ed2f999ff105591f8e2b3b8b66acd5fe.jpg

861-21.jpg.246ff353efa1c113b5630d54e2f89cca.jpg

Open barrel and note spring position;

861-22.jpg.a25569e0001dd7f2d6fecc4f01b5470b.jpg

Note arbor position;

861-23.jpg.7c484611d9af822dbe91599a28178744.jpg

Install new spring;

861-24.jpg.370d8488694057383e44961c46e6d91a.jpg

861-26.jpg.100763bb938b900081029c1ee9937ed6.jpg

Install arbor, grease/oil and close barrel. Mount driving pinion for hour recorder 1791 and friction spring 1792. Grease as per manual.

861-27.thumb.jpg.f305d29df619b163daf70841378f6d30.jpg

Service crown wheel and click. In my case the little screw of the crown wheel center was too tight and deemed not worth the risk. Applied some oil in the wheel groove.

861-28.jpg.1be4c7a487f3098c44f2a075f1455324.jpg

 

Now as for replacing the screws after each removed component; During the assembling I encountered a problem placing the pallet fork bridge and good pivot engagement of the pallet fork. After quite a few nerve-wrecking attempts, I noticed that a replaced screw on the other side of the main-plate stood proud of the main-plate and prevented the pallet bridge to seat. Once corrected, all fell in place .......

861-31.jpg.3f458fa5cf46c4bef5e6e72048a2bd62.jpg

Assembling of the chronograph is the reverse of the above. Greasing / oiling is done as per attached manuals.

Below; the movement is back together, running and all functions work .....

861-final.thumb.jpg.b67fb46451fe659d40f6076914ccbc2b.jpg

Tomorrow adjustment of the daily rate & bear error.

As said, I may or may not follow up on the case restoration. Cleaning the dial is another challenge .......

Hope this walk through is to somebody of any use ....... ;-)

Roland.

 

 

 

 

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861-32.jpg

Edited by Endeavor
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Nice saved watch . Like this Speedmaster mark II models a lot. Not sure the black sealing kit is black  sealing kit though? The old Omega gaskest has a tendency to get  like that after a few years. Like rubbery oil. 

So i think he used the right gaskets. 100% sure. Check omega gooey gasket. 

download.jpg.b3b4bf1efced9a581faa6ddae7586f7b.jpg

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To add to my story above; Marks video's Omega 865 contains also some valuable tips and is highly recommended. I also replaced the chronograph driving (or "wheel over 4th"-) wheel before installing the escape wheel and pallet fork. The balance capstones (Incablock system?) had hinge-type anti-shock springs.

@rogart63 Thank you for pointing this out Roger. I wasn't aware of this phenomena and the seals looked indeed like that; completely dissolved! Not only that, the rubber / "tarmac" had eaten the tachometer print behind the crystal as well! Perhaps the GFW wasn't the biggest after all !? Next to the sheared off screw that is. If the seals weren't his fault, my sincere apologies to him....

Very strange that a company like Omega used seals like that? Something went wrong in the R&D? Now I have to get it off the dial...... and have to find out how? What medium to use without harming the dial?

Has anybody any experiences with setting the glass. Even though it is claimed it can be done by hand, I also read "horror" stories if it is attempted without the proper guide ring:

FittingMineralCrystals_zps4e7d2593.thumb.jpg.5a00085ed4d1f225e65c65612bb4394e.jpg

From what I've seen, a tachometer glass is in between €60 - €80 ex. postage and a bit too expensive to give it an unprepared "go". Is there anybody who has this guide ring or knows where to purchase it? (please PM me if deemed required)

Anybody any idea's of how to "polish" the case and keep (enhance) the "star" pattern? Or else; Any recommendations or addresses of people who could assist me?

Any help would be highly appreciated !

Best regards: Roland

 

Edited by Endeavor
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Ref the sunburst finish on the case, 

To do a perfect job, you need a lapping machine. 

Short of this, it is possible to achieve a reasonable finish with abrasive sticks. A basic jig will help keep the grain straight and concentric. There is an excellent thread on thewatchsite describing one approach to this. I have included a link below.

http://www.thewatchsite.com/21-japanese-watch-discussion-forum/32439-work-progress-putting-freshness-back-now-added-how.html

For what it's worth, I think I would leave that one alone, it doesn't look too bad at all. It is all down to personal preference. Personally I prefer a bit of wear with nice crisps edges to a refinished look.

Edited by oli
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@oli Indeed, my first research pointed in the direction of starburst grinding, or sunburst finish with a lapping machine. Thank you for the link, but I can't see / open the pictures. This is what I get to see;

5958a64955348_ScreenShot2017-07-02at09_51_50.png.e3844567a93f4136b6b38a61684a355c.png

Any tricks to make them visible or do you have the same?

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The missing pictures is due to photobucket changing their policy and holding everyone to ransom in the last few days.

Photobucket will no longer allow photos hosted by them to be show elesewhere unless the account holder pays around $400 US a year, despite the fact this was exactly what most people had signed up with them before over the last 10 years. Needless to say I've not heard of one person say they were going to pay yet, but have heard many say they were closing their photobucket account.

Edited by Tmuir
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Sorry about the link, pics were working only a few days ago, as Tmuir is saying it seems to be a recent issue with Photobucket. Apologies I should have checked before posting, I just copied it from my favourites!

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The original seals were most likey nitrile rubber, which is less chemical resistant than fluorocarbons or fluorosilicones. The deterioration may be due to the wrong type of lubricant being used. However, a while back I picked up a NOS Record ladies watch and found the same deterioration on the crown seal, so maybe not. Rubber is susceptible to damage by heat, oxygen and chemicals, sometimes it dries out and goes hard, sometimes it rots, but it certainly doesn't last forever.

Isopropyl alcohol does a nice job of cleaning off the goo, but not sure if the dial lacquer will like that.

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Great post and excellent work Roland, it's been quite a time since we've been treated to a post if this quality.  I'll certainly be using it for reference when I get around to servicing my Speedy!

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@StuartBaker104 Thank for the tip. I just started cleaning the case goo with white spirit. It seems to take off the goo ....... whether the dial can stand white spirit ....... very careful try and we'll find out.

@Geo  I thought I had nothing to say and to share on the forum anymore, but here you go ! Hope it comes to any use ;)

I just took the pushers out and, needless to say, those O-rings were gone too;

861-33.jpg.1df871cf1f3a8aa99bc344f0b9b5ee6f.jpg

I think I will let everything soak in white spirit for a while. That can't harm the case. Not sure if the tubes have to come out ? Any thoughts?

Edited by Endeavor
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@StuartBaker104 Thank for the tip. I just started cleaning the case goo with white spirit. It seems to take off the goo ....... whether the dial can stand white spirit ....... very careful try and we'll find out.

@Geo  I thought I had nothing to say and to share on the forum anymore, but here you go ! Hope it comes to any use ;)

I just took the pushers out and, needless to say, those O-rings were gone too;

861-33.jpg.1df871cf1f3a8aa99bc344f0b9b5ee6f.jpg

I think I will let everything soak in white spirit for a while. That can't harm the case. Not sure if the tubes have to come out ? Any thoughts?

If you going to replace the gaskets in the pushers. Just let them be. If you are replacing the complete pushers? Remember that they a loctite in. Takes a  little heat to get the out. That is best done when all the other parts are taken of. You could probably find some generic gaskets for the pushers. 

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@rogart63 Thank you for your explanation ;)

I'm not sure which of the two options it will be. The old pusher O-rings are of no use anymore. I do assume that there is a special tool for removing / replacing the threaded(?) tubes. Either way, I'll order anyhow some loctite 243, general purpose ;-)

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@rogart63 Thank you for your explanation ;)

I'm not sure which of the two options it will be. The old pusher O-rings are of no use anymore. I do assume that there is a special tool for removing / replacing the threaded(?) tubes. Either way, I'll order anyhow some loctite 243, general purpose ;-)

I have done it but used an old pusher cap . A  friend of mine did a tool for it. We took an old SS rod and welded a pusher cap on it. Works perfect. There is special Omega tools but they cost a fortune. I haven't tried yet but i have a Chronostop that is getting a refurbished case. So there is  pusher on that has to have some new gasket. I  measured the old gasket  and i  think a 1,00 x 0,75 x 2,50 mm gasket would work?  The original Omega would cost £9 a piece.  And it takes two in each pusher.  Lot of money for nothing? :(

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@rogart63   Thanks a lot Roger for your tips and information ;) Smart idea that with the old pusher cap connected to a SS rod ! :thumbsu: 

I have to see what the best solution will be? There in now an unique opportunity to restore the whole watch to its old luster and money is, as long as it is well- & justified-spend, permitted. When I can get the original parts, at reasonable prices, I will do so. Else, generic parts are the only option left. Given time and with the help of people like you, the right solution will magically appear ....... :)

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If you send me the numbers by pm , I can go through my stock of Omegaparts, see if I have them...just let me know...

Btw, the movement looks pretty good, except for some dirt....:biggrin:

Edited by Watchtime
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To conclude this walk through, here are the latest pictures of the Watch-o-Scope. I would have liked to see a bit higher Amplitude and perhaps / hopefully it will climb a bit further in time? A slight "wave-pattern", which is already visible on the graphs before the service. Again, not much to do about ....

As for the case "Sunburst-lapping" and setting of the tachometer glass, I most likely need to source some professional help....... (under investigation) ......

Once all is build in, case done & glass set, perhaps a little more fine tuning of the Daily-rate;

Dial Up;

595f6076d9be9_OmegaAfterDU.PNG.93194e3ad57678f7e767cd33c10874a6.PNG

Dial Down;

595f607512243_OmegaAfterDD.PNG.956ba32b5f9a0b8ee6683c6eb7f45bd3.PNG

Crown Up;

595f607371d9b_OmegaAfterCU.PNG.eaf80209be98058276521dcf68b8c997.PNG

Crown Down;

595f6071c5e93_OmegaAfterCD.PNG.4b921d3eb5384d0affe0d6eb9d48f564.PNG

Doesn't seem too bad for a 42 years old movement ......

I'm happy with it .....

That's all folks ! ;) 

Roland.

 

 

Edited by Endeavor
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  • 4 weeks later...

That's a cracking write up, I've de cased mine and sent it off for lapping. 

This will be handy when I come to re case.  

Didnt realise the two small chrono hands were different tube sizes for a start  

anyhow I'll post pics up when I get her back  

 

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  • 1 month later...

Latest and some additional info;

Since the Omega was a "back-up" for the owner, it was decided not to "lap" the case. Instead, I just gave it a very light polish.

The pusher O-rings were replaced by Micro O-ring gaskets from CousinsUK; 1.70 x 0.45 x 2.60mm

Before one can install the glass, the movement, complete with hands, has to be put back in the case. This to orient the top of the glass with the 12-o-clock marker on the dial. The housing itself doesn't have an orientation point.

I found out that installing the hands caused some paint to come off. Due to age, the paint on the hands had become like plaster on an old wall. It had lost its adhesion to the metal and cohesion held the thin paint-layer together. Just pushing the hands back caused the paint to break and flakes to fall off....... Hmmm <_<. Taking great caution was the best I could do.

For installing the glass, a special tool was required. Friends helped me out and instead of just making just a "guide"-ring, they made a whole sophisticated tool ...... out of materials they had laying around ! First here the dimensions and tolerances of the case and glass. The case ID, measured with my caliper is 36.54mm.59ba52e3ba298_KastID36_54.JPG.3c7465fbfe693bef898b85f024c3b4e3.JPG

The glass OD is 36.48mm59ba53b5aeaeb_GlassOD36_48.JPG.9b3719e0b16a2e278c131214089c41d4.JPG

in total a 0.06mm tolerance.

The tool consisted of an internally tapered PVC inner-ring, a re-enforcement PVC outer-ring and a pusher. The internal tapered inner-ring was at the bottom so precisely machined that the glass, without an O-ring, was "air-tight" .....the top was wide enough to insert the glass + O-ring....... a fantastic job they've done !!! :thumbsu:

PIC_4976.thumb.JPG.0ef46a93d562263a00119e1271125634.JPG

PIC_4977.thumb.JPG.fa33d9b3f9546b86de836fd68ec6ab59.JPG

Smoothed the internals and O-rings with silicon-grease and the installation of the glass was a breeze. The "60" glass-marker was spot-on, even though I later found out that the glass can still be rotated. Perhaps this due to the low friction of the silicon-grease?

After installation of the glass, I tested the chronograph and the daily-rate. Had the Chronograph run for 14 hrs without a hitch. Adjusted the daily-rate and while wearing the watch it ran +4.5sec / day, BE 0.2ms. I've given the DR a little tweak so it runs now even more precise and the watch-case was sealed off with an original Omega back gasket; CousinsUK: X13216.

Today the watch has been send back to its owner. In my opinion the below picture doesn't justify the real looks ..... and compared to the first picture on top of this thread, I like to think that I saved the watch from water damage, given it a good service and made it presentable again... for sure, it runs like champ !

I hope the owner thinks so too and that he is happy !!

PIC_4975.JPG.7651e4bb28d4c427c9d8d75402dbeb97.JPG

Regards: Roland.

 

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Did you ever manage to gte the amplitude any higher? I've occasionally found this to be a problem with the "later" Omega movements with very fine pivots. Sometimes requires additional cleaning, especially at the balance stones.

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