Seiko 7A38 - by the numbers

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Forum Home > Bend it, Mend it - Mods & Wreckers > Pushers for the 7A28-7009 'Alien'

Sir Alan
Member
Posts: 457

I recently acquired a pretty good condition 7A28-7009 'Alien', the black coated one (so not the 'Ripley' silver version). Shortly after this, I picked up a salesmans sample case (no movement, and also no clasp or fittings), with the intention of combining the two to make one good one.

This in itself was a pretty straightforward operation, leaving me a complete watch in almost NOS condition and a part watch in used, but still good condition. Then the seach for the hard to obtain extra links and replacement pushers began .........


I thought I'd write up the pusher replacement, as I haven't seen any threads showing this.

Here's the watch with the original pushers:



everything looks pretty good here. But, this side on shot shows the inevitable cracking to the plastic pushers:



Here's the left (lower) pusher, pulled off its metal stem:




You can just make out the hairline crack at 9pm. This split was enough to allow me to pull the pusher off the stem. Here's the right (upper) pusher:



not a pretty sight - completely cracked and a loose fit over the stem. You can see I did try superglueing it, but the brittle nature of the glue, with the brittle plastic wasn't a good combination.


I'd resigned myself to making some replacement pushers, but not having access to a milling machine meant this was a job that was likely to take some time and probably need several attempts before getting it right. 


Well, luckily I found a source of these pushers and 4 of them arrived last week. So, it was pusher replacement time :D



However, this is where it got a bit more complicated.

I'd wrongly assumed that the yellow pusher was a push / friction fit onto the stem, and that it would be easy to push replacements onto the existing stems.

No, the pushers are a very tight fit onto the stem, and I think that trying to pull them off the stems they come fitted to, and/or trying to push them over the existing stems would probably result in cracking them - which would kind of defeat the object of the exercise :roll:


So, it was time to remove the pusher block, attached to the side of the watch with two phillips screws.

Here we are:



and the underside, with the pushers off:



and a shot of the inside:



each pusher stem is held in place by one of those pesky c-clips, so out with the c-clip pusher tool:



to give this:



and this:



BTW - you've probably seen this part for sale on ebay, but if you look, you'll see that it doesn't come with the housings for the pusher stem. Without these that part is useless, and I don't know how easy it would be to get them out of an existing block.


Here's a side view of the watch with the pusher block removed:




from this, and the other pictures you can see that the pusher end (where the c-clip is fitted) simply depresses the pusher on the watch itself.


Very simple, but prone to one problem. You can see (if you look carefully) at the pictures of me holding the block, and the pusher, spring and c-clip that the tip of the pusher is slightly bent. This is caused by the pressure of pushing the pusher against the pusher in the watch, at an angle. This and the fact that the tip is weakened by the indentation to hold the c-clip.

3 of the 4 pushers I replaced were all bent, one badly enough that trying to straighten it (to pull it out) resulted in it snapping off.


Here's the block with new pushers:



lovely :P


And fitted back to the watch:



and here, on my full watch:



One word of warning. The screws that hold the block onto the watch are a real b&gger to get undone.

I did the 'part' watch first, and typically whilst they were hard to remove, they did come undone without too much damage.

On my complete watch (based around the pristine sample case), both screws were really tight. The lower screw finally relented (with a snap/crack type noise) showing evidence of threadlock on the thread (a white residue).

But, the upper screw just wouldn't move, and I ended up rounding out the head, :mad:

So, it was out with the dremmel and some very very careful drilling out/off the head. I managed to do this without causing any damage to the block, but once the block was off there simply wasn't enough of the screw protruding to do anything with it. So, whilst the block is now held on with one screw, I need to find someone who can drill out and re-tap.


Oh well, all part of the learning process.


November 5, 2012 at 2:22 PM Flag Quote & Reply

fdawg4l
Member
Posts: 2

This is really informative and the bit about the threadlock is my experience exactly.  Actually, I think I've nearly rounded out the  lower screw and am hesitant to mess it up some more.  And the bit about bending the tips of the piston (?) which actuates the button on the watch itself is exactly my problem.  The reset pusher is useless on my newly acquired 7a28 7000.  I was hoping I could rip the bracket off, have a look, and unbind whatever was bound up in there and get things to reset adequately.  Alas, for not.  At least for the moment.


Anyway, if I may ask, where did you get the replacement pushers?  I have access to a (few) 3D printer(s) and was hoping I could get a hold of some genuine (or reasonably genuine) replacements and try to copy what I could for when I ultimately crack them and need replacements.


Also, the housing and bracelet of mine is pretty rough.  The paint is scratched and worn from time.  Any tips on how to restore that?

Lastly, the face ticks are still somewhat yellow and the face itself is more grey or white from what looks like sun damage.  Have you ever replaced the face?  Any tips you could give me would be greatly appreciated.


December 6, 2012 at 2:32 AM Flag Quote & Reply

Sir Alan
Member
Posts: 457

Hi there :)

There are yellow pushers for sale on SCWF. But, to fit them as-is you'll need to get the block off. I really think you'll crack them if you try to fit just the plastic part onto the piston part (though if you heat it up gently that might prevent this ..).

I really wouldn't know how to restore the black coated cases / bracelets and from what I've read to date short of a re-spray which will look worse there isn't any solution.

Replacing the dial, hands, tachy ring, glass are all things I've done and are very easy with a good set of tools and a fair degree of patience. 

The problem is finding parts to replace them with!!


Do you fancy posting some pictures of your watch?



December 6, 2012 at 4:38 AM Flag Quote & Reply

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