This Seiko 6139 Service is one of the more interesting watches on the work bench this month. These watches hold a exciting place in the history of space exploration and horological history The Seiko automatic chronograph was the first of its kind to go to space and arguable the 3rd automatic chronograph to come to market. This Seiko 6139 Service includes a complete strip down, cleaning and assembly of the watch.
This particular watch has some sentimental value to the customer as it was owned by their father. It has been previously serviced a couple of years ago by another service provider. The owner tells me it has not kept time recently.
Seiko 6139 Service – Disassembly
Upon opening the case it was apparent the has experienced some water ingress. The gaskets on the pushers were a older than expected and tell tale watermarks left on the steel components.
Seiko 6139 Service – Cleaning
With the watch broken down into component parts it can now be cleaned and dried followed by inspection. Everything came out of the wash in good shape. We noted the spring for the bottom pusher was a little worse for wear and opted to replace this with a new spring wire. All the other parts were in good shape.
Seiko 6139 Service – Assembly
A small amount of anti-slipping grease is applied to the inside of the barrel wall before the mainsping is installed. The mainspring was in good shape so it was reused in the original barrel.
Once the mainspring barrel is assemble and resealed the train can be assembled applying oil to the jewels on each plate after it is screwed into position.
A new Spring was produced as the old one had seen better days. The original can be seen on the white paper in the left photo above. After the completion of the new spring the pallet fork and balance assembly can be placed into position and screwed down. We can then test the movement is operating and assess any potential issues.
After the escapement has been assembled and the movement has sprung back to life, the jewels on the mainplate can be oiled. Following this the assembly of the keyless works the cannon pinion and minute wheel followed finally by the date assembly. Typically when completing the movement assemble during the Seiko 6139 Service the movement will be left running in a sealed container for 24 hours before the watch is fully assembled. This allows us to monitor the movement so we are satisfied with the Seiko 6139 service outcome.
The dial and hands can then be be applied to the movement and we can test the chronograph function a number of times to insure the start stop and reset functions are all working correctly without any slipping. The movement dial and hands can now be cased into the freshly cleaned case. The gaskets for the pushers, crown, crystal and caseback were all changed during assembly in accordance to the original specification. The OEM gaskets are no longer available from Seiko so we use the finest after market gaskets we have access to which allow us to give clients a 24 month guarantee.
Servicing a vintage Seiko 6139 chronograph requires precision, expertise, and a deep understanding of its unique mechanics. At WellingTime, we bring years of experience and a passion for horology to every timepiece we handle, ensuring your Seiko runs smoothly and reliably for years to come. Whether it’s a full service, restoration, or repair, we are committed to delivering top-quality craftsmanship. Contact us today to give your chronograph the attention it deserves, and let’s keep your timepiece ticking flawlessly. For Almost daily updates follow us on facebook.
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