Seiko 6309 intermittent stopping of the seconds hand at the same positions

[Disgrace]

Hi everybody, I recently got a relatively cheap Seiko 5 from the 80s on ebay. It runs fine which is why I didn't intend to clean and relubricate it, I just cleaned the case and bracelet and shined it up a little.

Well, it runs fine until it doesn't.

In a not-predictable pattern, the seconds hand stops at the 46 seconds/ 51 seconds mark, in every orientation. It does a little stutter for two seconds, as if it's running into resistance and then stops the whole movement.
I can guarantee that the hand is not touching the crystal, the dial or any of the other hands. I have quadruple checked. Every position of the hour/minute hands has the same effect. The issue also persists when the movement is outside of the case. I have inspected the hands very closely and can rule out touching.

My second thought was magnetism, turned out the watch and its metal bracelet were quite magnetic. I demagnetized them and for about 20 min the watch ran swimmingly in the case on my weishi 1000, until i took it down and the same problem sarted again while wearing it.
Now the watch sometimes stops, sometimes doesn't.
I could observe on the timegrapher that, just before the movement stops, the movement produces some serious snow on the graph, usually it's running at about 0-0.1ms beat error and the difference is quite striking. I think demagnetizing was part of the solution, as the watch runs less fast now as well. When it passes the 46s without stopping, the graph image ranges from completely identical to normal operation to quite snowy. So it seems like not every rotation generates the same amount of internal resistance.

However, the stoppages are too frequent too ignore and require some significant shake to overcome. Then again, if you free it at the 46s mark, it loves getting stuck again at the 51s mark once more. It's an issue too big to ignore. The movement itself looks to be in decent condition. I took off the automatic winding mechanism to have a look at the center wheel, however I did not find any dirt or bent teeth on that wheel. If I decide to take it apart further I am kind of forced to clean and lubricate the whole thing. While it had the winding mechnism off I also wound the mainspring up with a screwdriver, so power cannot be the issue either.

Does anyone here have any idea what else I could look into? The fault pattern is very confusing to me as it runs fine for 20 minutes and then just get's stuck again. My next step would be to take apart and clean the movement, though as I said I would like to keep this watch mostly untouched.

I strongly suspect that there is a bent tooth or a in some other way broken wheel somewhere in the movement, but I really don't want to open it up and service it since it runs awesome besides the stoppages (+15s/day, 215 amplitude, 0.1ms beat error).

Any help or input is greatly appreciated!
 

[RichardHarris123]

Saying it runs well, is like saying a car that does 0-60 in 3 seconds and 200 mph but breaks down every 10 miles runs well.  

It needs disassembling, parts inspected, if all well reassembled and lubricated. 

Edited April 6 by RichardHarris123

[Disgrace]

4 hours ago, RichardHarris123 said:

Saying it runs well, is like saying a car that does 0-60 in 3 seconds and 200 mph but breaks down every 10 miles runs well.  

It needs disassembling, parts inspected, if all well reassembled and lubricated. 

Well, I can't argue with that, you're right. I was just holding on to hope that maybe I didn't make a bad purchase for once haha.

Thanks for your input.

[Nucejoe]

 I don't see why in classical watch repair , disassembly is not practiced as  A process of elimination.

Remove the seconds hand, once sure it ain,t  the bad guy !! 

Remove the minute hand , continue ...

Find the bad guy, call the police. repair or replace the sucker. 

A good clean and lube wont hurt.

Enjoy your watch in goood health.

Rgds

 

 

 

Edited April 6 by Nucejoe

[watchweasol]

Hi no easy way out . Possibly damaged or worn tooth or teeth, dirt who knows. Dismantling cleaning and a good lubricate on re assembly. Inspect each wheel whilst re assembling for possible problems.

[Disgrace]

A little update on this if anyone is interested:

I have found some time to open it up and really have a proper look at the movement. The markings indicate that it hasn't been serviced since August 1992. This seems consistent with the state of the movement, as there were small pieces of gunk built up between teeth, under the mainspring barrel etc. . While I couldn't identify a specific piece of dirt that was impeding the movement, it seems highly likely that this was the cause for the stoppages. It's proving somewhat difficult to clean the teeth on the escape wheel and the center wheel, but a few more rinsings in lighter fluid/99,9% IPA should do the trick (I would really love to have a cleaning machine).

Overall the movement is in good shape, all of the jewels look great and it honestly just appears to me like the issue was a lack of service.

Obviously at this point in time the movement is not back together, so I will refrain from celebrating until the thing is actually ticking away and keeping good time!

I will update once more once I've put it back together.

[watchweasol]

Hi. At least you found a contributory factor, it needs very little to stop a watch so a good clean should suffice, get some good oil  the likes of 9010, it available on the net in small phials so no need to spend a fortune.

[Disgrace]

Even after thorough cleaning unfortunately the issue persists. I have made sure that all wheels are perfectly clean, no teeth are chipped, no gunk is left built up on them etc. yet the issue is not gone.

When reassembling the movement I of course checked if the wheel train moves freely as that was the suspected cause of the issue before. And the intersting thing is - it does - but only in the "wrong" direction.
Driving the wheeltrain by turning the mainspring barrel in the opposite direction as it would turn in normal operation, all wheels spin freely, and continue spinning for a few moments even after I stop providing power by hand. They behave the way I'm used to and have seen with other wheels before.

However: When I apply torque in the opposite direction, the power delivery througout the train is not smooth or continuous. While it does turn, there are stages of increased resistance in the train. In addition to this, you can hear a slight "rubbing" sound whenever the trian passes by this point of increased resistance. The sound, to me, is more indicative of a surface rubbing on another surface, rather than the teeth of two wheels getting stuck within each other. Installing the click and putting a wind in the mainspring confirms this same issue, it does unwind and all wheels are powered, yet when the power reserve approaches depletion, it doesn't have enough power to push the wheeltrain past this point of friction. The slightest bump on any of the wheels will free the train, make it spin for however many rotations and then get stuck in the same way. You can do this several times before the power is actually completely depleted.

This has really left me dumbfounded. I have inspected all of the wheels, pivots, teeth etc. on the entire wheel train and can't find any traces of dirt, any bent teeth or any warped or out of plane wheels. Besides: If one of the wheels was bent and rubbing up against some other part of the movement during a rotation, shouldn't it be doing this regardless of the direction of the rotation?
This is supremely confusing to me and I can't figure out for the life of me why there is increased friction in only ONE direction and not the other.

Installing the balance yielded the same result as before the disassembly: the watch runs great for about 50 seconds and then get's stuck when the wheel train get's bogged down.

I mentioned earlier that there is a periodic scraping noise that can be heard when the gear train turns fast, this noise is not present when turning the train the opposiste direction.

Does anyone have any ideas about which parts of the movement I can check for rubbing? I found no signs of wear or scraping on any of the bridges etc. so what would cause this periodic friction in one direction but not the other?

I am very much a novice and have never dealt with such an issue before so I would love to hear what you people think about this. Thanks.

[HectorLooi]

This sounds like one of the pivot holes has worn and become elliptical.

Can you post some photos of the plates?

[ManSkirtBrew]

1 hour ago, Disgrace said:

Besides: If one of the wheels was bent and rubbing up against some other part of the movement during a rotation, shouldn't it be doing this regardless of the direction of the rotation?

As I was typing this, @HectorLooi expressed the same idea. It's possible that when a wheel is pushed in the opposite direction it cants a little, or lifts up in its setting.

I'd check end shake on everything first, since it's already assembled--I had a Seiko 6139 where one of the upper bridge jewels was pushed up a bit and caused it to behave unpredictably.

Then I'd probably take all the wheels out and reinstall one at a time until I found the noise.

Also look very closely at the bridge and flat parts of the wheels for wear marks. Look for shiny spots.

[Disgrace]

1 hour ago, ManSkirtBrew said:

As I was typing this, @HectorLooi expressed the same idea. It's possible that when a wheel is pushed in the opposite direction it cants a little, or lifts up in its setting.

I'd check end shake on everything first, since it's already assembled--I had a Seiko 6139 where one of the upper bridge jewels was pushed up a bit and caused it to behave unpredictably.

Then I'd probably take all the wheels out and reinstall one at a time until I found the noise.

Also look very closely at the bridge and flat parts of the wheels for wear marks. Look for shiny spots.

 

1 hour ago, HectorLooi said:

This sounds like one of the pivot holes has worn and become elliptical.

Can you post some photos of the plates?

I don't know how I could miss it, but your suspicions were right: it looks to me like one of the pivot holes is elliptical, and quite clearly so. There also seems to be some scoring from the ratchet wheel on the bridge, which is odd, as well as the other pivot for the barrell bridge on the main plate.

I suppose I need to find a replacement wheel bridge at least, what do you think about the other damage on the mainspring barrel pivot?

Also perhaps a little unrelated: using lighter fluid to clean balances seems to make the balance springs stick to themselves, what other cleaning agent should I use?

There are some wear marks on the other pivot for the mainspring barrel as well

[ManSkirtBrew]

19 minutes ago, Disgrace said:

what do you think about the other damage on the mainspring barrel pivot?

The hole in the main plate looks kind of oval from here, but it could be perspective. You'll probably want to put the arbor  and bridge back in and wiggle it around to check for side shake. I'm not sure about the 6309, but for the 6139 you can get a jeweling kit to replace the barrel bushings, if you're looking to make extra work for yourself

19 minutes ago, Disgrace said:

using lighter fluid to clean balances seems to make the balance springs stick to themselves,

I found the same thing, and is one of the reasons I bit the bullet and switched from lighter fluid to L&R 566 in my ultrasonic. It's a night-and-day difference in cleaning quality.

That said, I still clean my balances, hairsprings, pallet fork, and cap jewels separately in hairspring dip. It dries fast and leaves no residue. I get mine from Esslinger here.

Edit to note the fact that it dries fast also means it evaporates quickly from whatever vessel it's in. I used to use the guy on the right, which everyone sells. Then I found the one on the left and it's once again a game changer. The ground glass seals very well and minimizes evaporation. Link to previous thread on the topic.

Edited April 14 by ManSkirtBrew

[HectorLooi]

Here's a video of how to repair a worn barrel hole with a jewel, for the future when your skill level and tool collection has caught up with the problem present in your watch.

[Malocchio]

4th wheel bushing hole wearing oval is typical for these movements. The bushing has possibly also been moved while pressing the seconds hand too hard so the end shake is so big that the pivot might even fall out of the hole, stopping the movement, especially with an oval hole. The bushing can be replaced with a jewel from a jeweled train bridge. I replaced one 6105 4th wheel bushing with a jewel from a 6119 train bridge.

[nevenbekriev]

The effect that You describe (no friction when turning train backwards and noise + friction when turning forward) is due the oval wear of the 4th wheel bush. The oval lets the 4th wheel tilt and get closer to the escape wheel in normal direction rotation, and thus the mesh with 'scape pinion is wrong. There is a simple way to confirm this - mark the bush, remove it and press it back but rotated to 180 degr. This will restore the correct wheel position and mesh when rotating the train in normal direction. The mowement will start working normally. Well, this is not perfect soluion of the problem as the oil retention will be not as good as with new bush, but if You lubricate with 8200 grease, it will stay in place and work good. Of course, placing a stone there is good, if You can find one with correct sizes.

The hole for the arbour in the main plate looks rather punched than weared. So if You have not punched it, then someone before You did. It means that You have to check if the arbour stays upright, as closing the hole by punching it may lead to shifting the hole. What You actually need to check is wether the barrel stays tilted when the movement is wound and let to unwind by train rotation, does it rubb on the bridge or the mainplate or gets dangerously close to the 4th wheel table, and if the mesh with the 2nd wheel pinion is correct. Wear of the barrel bearing holes may lead to similar problems too.

Lighter fluid is good for lighters, it is not ment for hairspring cleaning. Well it doesn't mean that it is not possible to use it for hairsprings. But if they stay sticky, then it means that the fluid is not fully evaporating or it has some oil in it solved. You can try to use hairdryer to dry the balance complete. If the spring is OK after drying, then You have the solution. If not, then source some pure hexane, acetone or another fast drying and clean oil solvent. Clean - put some drop on clean glass, wait untill evaporates and see if the glass is still clean.

[Disgrace]

Hello everybody, sorry for the late reply.

Thank you all so much for your help and your tips. I got lucky and found a replacement wheel bridge for cheap which actually ended up being in decent condition. I decided not to do anything about the mainspring barrel pivot since I didn't have the right tools and the barrel didn't have much endshake anyhow.

I am happy to report that the watch now runs great, I have regulated it to about +-10/s day which is fine by my standards. The timegrapher result looks decent as well, although beat error is around 0.6ms which could be better I suppose. Amplitude reaches over 230 quite consistently which I'm happy with also.
My lighter fluid has also been replaced by balance spring cleaning solution and now the springs don't stick to themselves anymore - who would have thought.

I'm super happy with this watch, it might not be worth a whole lot but it's awesome that I could restore it and it makes me wear it with pride.
To me it's a genuinely good lucking watch, it'll be my daily driver for a while.

Thanks again to everybody for their input! I couldn't have done the repair without your help.

 

Here are some images for those interested, the bracelet isn't original but I don't really mind:
 

 

[ManSkirtBrew]

Nice result, and a really handsome watch! You'll enjoy putting that on every single time.