First chronograph: 1972 Seiko 6139-6012

[ManSkirtBrew]

I've wanted a chrono for a while, and I found the Seiko "Bruce Lee" watches on eBay, and fell in love with the yellow dial.

Spent a few months looking around at watches in my price range, and they were mostly basket cases. Found this one in the UK, and despite having a black dial, it has the "railroad" bracelet I wanted and was in nice shape and in my price range, so I had to jump on it.

It runs after being wiggled around a little to wind up, so I'm taking that as a good start. Seller says the chrono start pusher doesn't work, and I can see why. Here are the disassembly pictures with where I'm at now. Took a break for the evening to keep watching Mark's chronograph course

[ManSkirtBrew]

Finally remembered to check the timegrapher before disassembly! Looks like a solid starting point.

More disassembly. Taking off the automatic works, the first thing I notice is different screws holding it down. An ominous start.

 

Although right below it, we may have found the correct screw, but also one with half rusted off. I was able to clean out the slot and very gently turn it out.

 

A little further down the movement, found a screw that is completely broken in half. I was luckily able to push on the corner of it to get it unscrewed.

 

Dial side looked pretty good overall.

 

And here's the whole thing apart. There's a kink in the mainspring that I don't love, so I'll be replacing that. I also noticed a cracked upper pallet jewel, and some of the bushings have a lot of wear. If anyone has resources for replacement jewels, I'm all ears, otherwise it's research time.

[ManSkirtBrew]

I also noticed that this spring for the chronograph start lever is around the wrong lug, badly misshapen, and the lever itself is badly gummed up and sticky. That would explain why it doesn't start, and should be an easy fix.

[thor447]

3 minutes ago, ManSkirtBrew said:

I also noticed that this spring for the chronograph start lever is around the wrong lug, badly misshapen, and the lever itself is badly gummed up and sticky. That would explain why it doesn't start, and should be an easy fix.

That is the hammer spring for the reset pusher, not the chrono start/stop pusher spring.  That is the correct location for that spring.  I've made the same mistake before.  It actually works when installed in either location shown in your arrows, but the post for the chronograph bridge is technically not where that spring is suppose to go.  That spring is badly misshapen as you stated, but it is currently installed in the correct orientation.

[ManSkirtBrew]

49 minutes ago, thor447 said:

That is the correct location for that spring.

Interesting. I was using Mark's disassembly video as a reference, which shows it around the other post and I figured that would also explain why it was so misshapen:

 

And sorry for mis-naming it. I'm still learning all the bits and bobs in here! I also (embarrassingly) forgot that we're looking at the back of the movement and got the flyback and start buttons reversed in my head.

Edited May 18 by ManSkirtBrew

[thor447]

4 minutes ago, ManSkirtBrew said:

Interesting. I was using Mark's disassembly video as a reference, which shows it around the other post and I figured that would also explain why it was so misshapen:

 

And sorry for mis-naming it. I'm still learning all the bits and bobs in here! I also (embarrassingly) forgot that we're looking at the back of the movement and got the flyback and start buttons reversed in my head.

I did this exact same thing on two watches, and both worked perfectly still.  A good friend of mine had a 6138-0040 Bullhead he purchased new in the 70's.  After it stopped running in the 90's he put it in a drawer and left it alone.  I was given the opportunity to do a service on that watch, which had never been opened prior, and can confirm that the spring was mounted not to the chrono bridge post, but to the column wheel lever post just below it in your picture.  In my (limited) experience, it appears to work in either location.  The manual is vague about this, as their graphic doesn't label that post, but judging by the closeness to the edge of the main plate, it looks like the column wheel lever post:

 

I made this same mistake on two of my YouTube videos, and a couple of people kindly pointed it out as well.  Here's a quick video showing me correcting this spring (although again it still works perfectly in either location - with a good spring):

 

[ManSkirtBrew]

Hah I just came back here because I watched Mark's re-assembly video of the same watch, and what do you know:

I'll check out yours as well, thank you!

Also, I have the 6139A and B manuals, but the B is just an addendum and doesn't have that nice image you posted. Any chance you have a link to a copy of that manual?

[thor447]

I can't remember where I originally downloaded it from.  More than likely Mikes website at MyRetroWatches.com.  He has an impressive library of manuals available for download.  Here's a copy of it.Seiko-6138A-Service-Manual-Colour.pdf

[ManSkirtBrew]

Ah, that's why it's different--that's the 6138A manual.

I have the 6139A manual, which shows a differently shaped spring:

[ManSkirtBrew]

hah, looking at donor movements on eBay...

I'm seeing a pattern here

[ManSkirtBrew]

While I wait for a donor movement hopefully chock full of usable scerws, I'm getting things clean and inspected more closely.

Guessing this was a repair on the barrel bridge at some point.

[ManSkirtBrew]

Parts movement arrived, and luckily most of the parts look a lot better than the original one. There's some wear around the barrel area so I'll be checking side shake there, but overall looks good.

Importantly it has the broken screws and spring I need in perfect shape.

Looks like we may have a Watch of Theseus situation here.

[ManSkirtBrew]

I'm doing close inspection on the parts to pick the best ones, and the barrel bridge from the original has a chipped jewel and that repair on it, so I'm using the other one. Only problem is there's some wear around the edge of the bushing in the center for the center chrono wheel.

The oil cup side looks perfect, but the wheel side looks like it's been poked with a pivot a few times.

It doesn't look like it's going to be a problem, but I was wondering if there are any techniques for cleaning it up a bit or burnishing the edges so it won't wear the pivots. I know the pivots are much harder than the bushing, but I still want to ask you more experienced friends.

The other option is of course pressing it out and replacing it with a jewel, but is that overkill?