Wristwatch restoration, servicing and repair

Seiko 6105-8119…

It’s been almost three years since I’ve written about a Seiko on the blog, so let’s have a look at this vintage 6105 diver.

(Click pictures to enlarge)

Replacing the 62MAS, Seiko’s first ever diver, the 6105 was produced from 1968 until 1977 and has become something of a Seiko legend. Having seen a rise in popularity over the last few years, values have steadily increased and all original examples in good condition are now highly prized by Seiko enthusiasts.

The watch was produced in two flavours, the cushion cased 6105-8110/8119 seen here, and also a slimmer cased model, the 6105-8000/8009.

You may see the cushion cased model referred to as the ‘Captain Willard’, so named because Martin Sheen wore the same model in the 1979 film Apocalypse Now.

Unfortunately time hadn’t been kind to the subject of this post and it arrived in poor cosmetic condition. Still in the possession of the original owner who logged hundreds of hours of diving whilst wearing the watch, it was finally replaced in the late 1980’s and has been resting in a drawer since then.

Although the case was in decent shape, the crystal was heavily scratched and as is common to many 6105’s, the lume had deteriorated and the resulting ‘rot’ had eaten away the plating on the hands and frames of the hour markers. You’ll notice too that the SEIKO logo is also heavily tarnished.

With the caseback removed I was pleased to see that the movement was still in good condition with no sign of rust or heavy wear, just a few patches of light tarnish on the winding rotor. The movement in this watch is the cal. 6105A, a 17 jewel automatic which runs at 21,600 bph.

The movement required no more than a routine service, so the majority of the work on this watch was cosmetic.

As can be seen in the dial shot above, the tarnish on the hands and dial markers was extensive, so much so that the chrome plating on the hands had been completely eaten away. Consequently, the owner opted to replace them with a set of 6105 aftermarket hands on this occasion.

The hour markers had suffered too but not to the same extent, so with the old lume carefully removed and a little work done to clean up the tarnish, the new hands, dial markers and bezel pip could all be re-lumed to match. The last job on the dial was to replace the tarnished logo.

The case was then stripped down, cleaned and rebuilt with new gaskets for the crystal, bezel and caseback, but the crown gasket proved to be problematic.

The crown gasket on the 6105 is a known issue as the original crowns were never designed to be serviceable and Seiko never supplied replacement gaskets for them (the whole crown would have been replaced as part of a service). When the crown is made, the gasket is inserted first, a thick metal washer is then pressed over the gasket and the edge of the crown is then crimped/folded over to seal the gasket and washer inside.

The only way to fit a new gasket is to prise out the washer, replace the gasket and try and re-insert the washer – I’ve never attempted the manoeuvre myself, opting to either stick with the original crown, or fit an aftermarket replacement. Here’s a picture of a crown from the internet that has had the ‘operation’ and while it worked, the result isn’t pretty.

Genuine NOS (New Old Stock) crowns can still be found for the 6105 and one was included with this watch, but as the gasket inside is already 30+ years old it is known for them to have hardened in storage, and unfortunately that was the case here.

In the picture below the crown on the left is the original crown in which the old gasket is barely visible after decades of being stretched around the case tube. In the NOS crown on the right, the gasket is clearly visible and, with some silicon lube and moderate pressure, it should slide over the case tube making a tight seal. However, on this occasion the gasket was as hard as rock, rendering the crown useless.

Thankfully the seller of the NOS crown had some more in stock and the gasket in the replacement crown was still soft, so the watch could finally be rebuilt and fitted with a new Seiko strap to finish the job.

Rich.

** Many thanks to Paul Stevenson for letting me feature his watch on the blog and also to Paul Briggs for his sterling work as the middle man. đŸ˜‰ **


One Response to “Seiko 6105-8119…”

  1. Adrian Baldwin Says:

    Hi Rich,

    Delighted to see a Seiko featured in the blog again. Has it really be three years since the last post on the brand? A great watch and and certainly one on my wish list.

    I hope that Paul is well pleased with your efforts, you’d think it was a different watch.

    Best regards,
    Adrian

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