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227 Posts
Discussion Starter · #1 ·
The 7549-7009 Tuna below, arrived some months ago overhere at the home of a forummember overhere. (we found out we are only a few miles separated)
Mario asked me to look at it.

You can read here how he got it,27861.0.html

If I remember correctly it arrived to the end of the week and on saturday I did some little testing to check if the watch was ok. ::)

I had some problems.... ???

The watch was not running and there was no way I could close the crown, If I closed it somehow the weakest touch made it jump out... :-\

I looked at the shroud screws and thought which morron would do such a thing. One original shroud screw was missing, one original was in place, the other 2 had been replaced by some screws which did rust and had a different pitch... :-[ [size=78%] .

I started working on the watch.
The original Shroud screw came lose... :celebrate:
Someone had already tried to remove the other screws, the philips head was more or less worn out. Time for the trick box with some different tools, like allens, multi head allens and torxes.
One of the others came lose after a fight..which it lost.. :celebrate:

the other screw broke of :-\ at least the shroud could be removed.

Left this for a while, first need to see if the watch was running after a new battery.

The bezel came off...without gasket, one clickball missing.

I opened the watch and the watch did run with a new battery...ok, now we can work to something.

I decided to drill out the broken screw first..I knew if the drill would break we would be in deep problems, although the shroud will hold by 3 screws, that one would be cosmetically fixed, just in case of.
Cosmetically fixed: I would have attached the head of the screw to the shroud and the shroud to the case by 3 screws. The head of the screw would only have a cosmetical function.

The drilling worked and went good, at this stage I stopped. I would like to fix the closing of the crown first.

At first I didn't know what was wrong with the crown, checked the old crown, tried a new crown, which was a tad better but not good.

Then I saw it...the first thread of the crown in the case was missing... :a102:
Never seen this before, I could not think of anything which could cause this.

If you look at the pics below, you can see that the crown at the right watch is deeper into the watch as the one on the left. BUT in the left one the crown is screwed close, the right one is open just pushed in, so it should go into the case a little more.

After some measuring and fiddling I found out that the bottom of the crown contacted the case and there was no way it could be screwed in....Case is /was toast.
I contacted some people with a great knowhow at restoring seiko divers. Verdict more or less: you need a new case. Yes, that would be the easiest and the best...but I don't see many of these cases.

So I tried a repair.
I shortened the crown, I used a new crown of a SBBN011 as these are cheaper as the ceramic ones. you can see what I removed in the second pic in red

I could screw the crown onto the case now, but now the crown tube was to long. Should I or should I not... ??? Ok, I gave it a go and I shortened the crown tube for a bit.

What a work.

And indeed, it worked, the crown screwed onto the case for around 1.5 turns. Yes, we are going good.
I installed a new crown gasket....but now the crown did not fit anymore...the crown is tappered outwarts to the outside, so I had to make that to the new crown. I had removed that by shortening the crown.

I thought I was there..but the deeper the crown goes, the deeper the stem goes into the movement and there is no room. :(
Every solution in this brought another problem. Thinking about a solution.......I had to find a way to make room in the movement of the stem and I found it.
Another option was to make more movement possible in the crown stem assembly which is more or less identical to the 6309's.
I found a way..but this was easier found than made.

I had to deep out the female part of the stem (yellow)

I had to flatten the male part of the stem (red)

Now these 2 parts could move more into each other.

That was the last big hurdle to take to get this tuna going.

I serviced the movement and changed the day finger which is a typical 7548 / 7549 problem. I cleaned the hands and dial as much as possible. I installed a new battery, new gaskets and a new crystal.
Tightening the crystal ring gave me the idea why the thread of the crown was broken. If you tighten the crystal there are no lugs to hold the watch, the only thing extruding the case is the probably someone had the crown screwed for about one thread and tighten the crystal and sheard of one winding.

the watch was done now, except for tapping the threads of the shroud screws. It was a search to find the correct tap, but I found it in a modelshop. Of course I retapped all four shroud screw threads.
I installed a few used shroud screws as new ones did not matched the lived and aged look of the watch.

I did wear it for a few days before I send it to Mario, I hope he is happy with a fully functional watch now after a more or less hopeless start.

Wear it in good health !


5,181 Posts

What a great job, excellent innovative approach to issues that would cause other folks to write the case off as junk. GREAT job!

Special Member
4,629 Posts
Luka, words cannot express how happy and thankful I am. Thank you very very much! I'm proud to own this Tuna and will wear it proudly from now on...


391 Posts
Great save Luka! Thanks for sharing a very innovative approach on this one! With people like you no Seiko should go down the drain without a fight! :You_Rock_Emoticon: :clap:

119 Posts
Wow! That's an incredible save, and a fantastic status report!
As if tapping out holes on an engine block wasn't tough enough, that's amazing.
Doesn't get any better than that. The world is richer one killer, functional Tuna!
Great write-up and great pics.

Super Moderator
3,300 Posts
Thank you for documenting the repair, it was good to get an idea of the thought-process- I'm sure you spend a fair amount of time just thinking, checking, measuring, thinking again...

I dub you "Luka, Patron Saint of Lost Tuna Causes"- you really brought that one back from the brink. Well done.
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