A staple of many watch enthusiasts’ collections is the pick-up-and-go watch.  The trusty quartz, ticking away in the watch box, oft neglected but waiting patiently for some attention.  In the armory of classic Seiko dive watches of the 1970’s and 80’s sits the 7548, the middle market quartz equivalent of the 6309 automatic divers and, if we’re honest, a higher quality offering than the second generation 6309 sold from about 1985.  Reflecting this higher tier status, the 7548’s generally cost a fair bit more than run of the mill slim case 6309’s of the same era, and in my searches I struggled to find one meeting the right balance of condition and price. Then in early 2010 I saw a 7548-700B on eBay, looking rather forlorn and described as ‘needing service, battery’.  I took this to mean anything from ‘it needs a new movement’ to ‘it needs a service’ to ‘it needs a battery’ but it otherwise looked in decent nick and so worth a punt. £37 sealed the deal plus another £13 postage and about 10 days later I received it. Here are two of the seller’s photos:

The watch appeared generally in very sound condition, sporting plenty of scratches and a couple of dinks on the case and bezel, a clearly trashed insert, lots of crud but a beautiful dial with lovely honeyed markers and hands that while not in perfect condition, were perfectly serviceable. The first thing I did on receiving the watch was to replace the battery and much to my relief is sprang into life.

So, with an apparently healthy movement, all that was needed was the usual clean, case refinish, new insert and crystal and gaskets all round. While I had been waiting for the watch to arrive, I had found a decent, but not mint SKX009 insert, and had also bought a NOS 6309 crown from Cousins. The crystal I was to order after having received the watch and in the end I opted for a flat, AR coated sapphire, to keep it looking as original as possible.

Let’s begin then. Out with my Dad’s old penknife and off with the bezel:

Plenty of muck in there. The innards of the bezel look pretty grim:

The insert is removed by inserting a scalpel blade between it and the bezel from the underneath and gradually working around the bezel until it works free:

The insert is now free from the bezel and can be added to the huge pile of worthless old Seiko parts accumulating in my parts drawer:

The final part of this process is to remove the gasket which usually, on a watch of this age looks like this:

and here’s some of the dirt liberated from the bezel:

Let’s return to the case, which appears pretty filthy too:

and in this shot we can see both the cut-out on the crystal retaining ring to aid removal as well as the somewhat battered state of the lugs:

A better view of the retaining ring cutout:

A knife blade into the cutout and gently lever the retaining ring off the case

Next, out comes the movement, movement ring, crown and stem:

Before moving on to the case, I decide to replace the crown, which looks a bit beaten up. First job is to separate the male and female parts of the stem (no sniggering at the back there), taking care not to lose the washer at the end of the spring:

In order to replace the crown, we now have to separate the male part of the stem from the crown itself. This requires a needle vice to secure the stem, whilst turning the crown anti-clockwise (Note: there are some who would advocate not using a needle vice for this operation as it risks damaging the operational part of the stem, suggesting instead that you hold the stem by the threaded part):

Here’s the new crown on the left and the old on the right:

and the whole lot reassembled:

That washer is important because otherwise the stem will not sit straight on its own accord.  The next job is to remove the crystal, crystal gasket, gasket retaining ring and chapter ring:

and we are finally ready to tackle the case. The first part of the exercise involves the use of pegwood sticks to remove most of the grime. Here we see the case, partly cleaned, with a goodish view of a significant ding on the lower right lug:

Having got rid of most of the dirt with the sticks, we now brake out the tooth brush and Colgate:

Here’s that troublesome lug, in the process of being reworked:

How do we do this. Well, this might seem a bit brutal, and it does take a bit of courage the first time, but this is my method of choice:

I’ll spare you the rest of that process, but it is rather time-consuming, tedious yet somehow therapeutic. Here’s the case post trauma, with a satin finish to the top, and a polished finish to the sides and back:

Right, now we are ready to reassemble. Or we would be if we had that crystal. After a 5 day wait for the rather excellent Hong Kong postal service to do its stuff, the crystal arrives and we are ready to continue. Here’s the refinished case, the chapter ring, gasket ring and crystal gasket:

In they go:

On with the rather lovely new sapphire crystal (with a frosted bevel – nice):

So far, all that is required is finger pressure, but the crystal retaining ring needs a crystal press to get it back on:

In goes the movement, crown and stem with some lubrication for the new crown gasket, a fresh case back gasket and on with the case back:

The bezel snaps on with firm finger pressure, following the fitment of a fresh, greased gasket:

The only things that remain are the new pepsi insert, a set of 22mm fat spring bars and a new rubber strap: