M158 case backs - for posterity sake

[dapellegrini]

In a previous thread I documented the nightmare I had trying to open a M158-5000 case back.  Long story short - after two weeks, hundreds of dollars in tools, and adding some nice marks to the case back - I ended up smashing through the front - sacrificing the dead (who knows if it could have been revived) LCD to keep some semblance of a case in shape.  Ends up the case gasket was fused to the case and caseback around the pushers and no amount of leverage would get it open.  Pushing through the front was easy, but came at the cost of most of the internals.

Here's that thread:
wristsushi.proboards.com/thread/23280/tricks-impossible-snap-case-back

Fast forward several months (and many M158's) and I have again found a case back that will not open.  Right now it is outside, sitting in the 114 sunlight for a few hours - I have not yet tried that (though I had tried a hair dryer to no avail last time).  I want to use this one to further (and as patiently as I can) experiment with different methods to unlock it.  More on that soon (I hope)

Anyways, in the course of collecting lots of parts watches, I have discovered there are 3 different case back designs for the M158.  Hopefully the show up in these photos

(Note most of my uncased M158's are SGP, but I believe these case back types are found on SS and SGP examples)

1 - notch at bottom right, no cut-out on case back - never had a problem opening one of these:


2 - notch at bottom left, no cut-out on the case back - only ever seen one of these (here) - and probably easiest to open because it gives you the leverage in the right place - around the buttons where things can bind up



3 - notch at bottom right AND cut-out in case back.  IME these are the nightmare versions - but not all the time.  The cut out in the case significantly reduces your leverage - which isn't a problem if your gasket is nice and supple, but watch out if not!


Sometimes the #3's come right open, but I'm now finding myself with the second that just won't.  

If some hot, direct sun doesn't work, I might next try leaving it in the freezer for a week.  And open to any other ideas you guys have.  Photos of that one soon

[inboost]

dapellegrini - I think we ought to try some Kroil flooded around the caseback as it's a good penetrant with that heat as the first go. I wonder if we couldn't get air pressure to help us some how. If we made some kind of a battery hatch to air nozzle piece we could pump the case up while holding it crystal down against a hard surface with some clamps as not to blow it out instead of the case back.  The other thought is to make a tool that mimics the battery hatch engagement as a handle that allows you to pull the back off.

Where you able to get the hatch off?

[dapellegrini]

inboost , is the the same thing as Kroil?





Unfortunately the hatch is trashed (I have replacements).  It is turned hard around the wrong side of the threading, and has the remains of a gasket smashed in the threading and over flowing out the back.  I didn't try too hard.  I could probably get it off with a nickel in vice grips and a lot of downward pressure... 

There is a video somewhere of a guy using epoxy to glue a wrench (if I remember right) to the crystal of an old Seiko to they pull it free...  

Another thought, if I gently carve out the plastic gasket around the crystal, perhaps some protection over the LCD and firm pressure would push it out the back?  Last time I used a center punch thinking the crystal will shatter and fall out - but its like safety glass and takes for ever to pull it out a piece at a time.  And the center punch (of course) ruined the LCD.

[inboost]

dapellegrini - I'd say not, but it might do the job? spray some into a little cup and then drip it around the perimeter of the case.

Yes, gluing tooling to the caseback could be another way out. I think superglue can be melted with high heat to get it to release but I've never done this. I remember someone doing this to turn a part on a lathe so it's pretty strong when done right! I just don't know the aftermath and how hard it would be to clean out of inscribed caseback data.

[dapellegrini]

Ok, it's out cooking in the sun for the moment.  Here's the penetrating oil I have:

www.amazon.com/dp/B00022VY74

Would you recommend Kroil in an oil can or the aerosol version?

[dapellegrini]

Well a few hours in the desert sun and the LCD went completely black, the case was too hot to hold at first.  The LCD regained normal color after a few minutes in doors.  No luck getting it open.

So I put the penetrating oil I have on hand around the caseback.  Let sit for an hour.  Also no dice.  I have ordered some Kroil.

I was able to rotate the battery hatch to the open position, but haven't yet got it to come up.  Still paying around a but with that.  

[dapellegrini]

And another case back opener bites the dust

[inboost]

Drat, that's terrible dapellegrini Why must you find these fused M158s to torment you so? I'd buy the Kroil in liquid form not aerosol as the spray out of any can is too violent for anything we do on the watch bench. I say spend your efforts getting the battery hatch off the caseback for now, maybe the penetrant will work over time to soften the bone to the caseback gasket. If this battery hatch is toast, why not superglue a rod to it and use it to try and pull the whole caseback off? In fact, clean the whole back of the thing off and glob a whole bunch of hot melt glue around it as well, maybe that will help?You could also try gluing the caseback to a flat surface and then use much bigger prying tools in the bracelet lug are to lift the case off the movement. Might be worth a try?

[Myles]

Can you superglue a flat piece of metal to the case-back, and use that as a lever to pry it off?

Acetone (e.g. nail polish remover) dissolves superglue.

[dapellegrini]

I may try the super glue route next.  Its been in the freezer since last night and I'm inclined to leave it there for a while yet.

A can of Kroil is also in the mail...

I was able to get the battery hatch off.  What a difference leverage makes. The module shows no signs of life with a new battery (no surprise there) and no battery corrosion visible from the open hatch (a potential small win)

This is my setup hatch remover:





You have to apply a fair amount of downward pressure, and go slow.

Here's the watch sales listing photos.  I paid very little for it - figured worst case I would get another case and bracelet.  Oh, and I was really hoping for a good dial frame.  This one is usable I think, but not perfect







I've amassed a small collection of parts for these watches.  One of these days I am going to nerd out on the electronic parts and see if I can't get at least one or two working modules back together.





It seems there are three things that typically go wrong with these:

1. The LCD goes bad, signs of leakage etc - I am not sure that is recoverable - certainly not by me
2. The electronics are shot - either some hidden issue, or corrosion.  The later is sometimes recoverable 
3. The mechanical parts are trashed - either by rust or battery corrosion or other.  I have not yet attempted a full dissassemly and reassembly of these parts - I typically just take the best looking one to put into a watch with a working module.  It does look like these should be serviced, cleaned at lubed every so often.

Here's a few examples of the mechanical parts:

In likely recoverable state:


In questionable state:


In terrible state:

[dapellegrini]

Well, I pulled the M158 head out of the freezer last night - must have been in there for 5 or 6 days.  Let it thaw overnight and spent an hour today trying to get the back off.  I bent another case back tool in the process - and discovered that if I use a cheap case vice upside down, I can get a better "grip" on the watch while I pry.  No luck.

Its now in the garage soaking in a thick application of Kroil...  This thing is on there so good, am I doubtful with the penetrating oil, but we will see.

If that doesn't work, I think next step is supergluing something to the case back.  Then epoxy, then trying the same on the crystal with an attempted reverse removal that doesn't destroy the movement...  Hopefully it doesn't come to that.

At this point, when it does come off, I won't be able to clearly say "this" or "that" did it.  Its like the pickle jar that won't open - then you give it to someone else and the lid slides right off - probably more about all of your previous attempts than the last one specifically...

More soon (I hope).

[inboost]

dapellegrini - best of luck, it's so disappointing when things go this way. Hopefully it comes apart 'nicely' and you're left with some good parts. Kroil is a really good penetrant that has helped me out of a few jams in my life. Fingers crossed it doe the job for you too. Cool tip on using the case holder upside down, that's clever!

Inboost

[dapellegrini]

inboost - how long do you figure would be max soak time?  I don't want to call it too short - will just leave it there for a week if that is what it might take.  Also, probably a silly question - this is sitting in my (hot garage) - does this still evaporate?  Should I plan on multiple applications spaced out at some interval?

[inboost]

dapellegrini - really hard to say. I would try and exercise the joint to help the penetrant move in. The temperature swings might do it well, and could some gentle squeezing and prying. If it were mine and I wasn't in a hurry I'd leave it until next weekend. It is a very light oil, so you might need to apply what evaporates / wipes way in your handling of it.

[dapellegrini]

I didn't jiggle it around any, but I did soak the whole case back in the Kroil - and then forgot about it for a week.  Last weekend I picked it up again and still no luck.  Super glue is on the way.

Also, I was pondering the specific case opener they show in the service guide:



I believe this is the Seiko S-280, which is hard to even find a photo of.  As luck would have it last night there was one listed for sale online and I bought it.  No idea if it will help - but at this point I will try anything - plus I quite enjoy collecting tools.




I think I will try the S-280 - then move on to super glue - to pry the crystal out for a (hopefully) delicate reverse extraction.

[dapellegrini]

Question: What would be the correct way to clean up this rust and corrosion, once disassembled?

[small]

I love the smell of Kroil in the morning...

I wish I could add a drawing, actually whish I could draw as well. I think you can gain some mechanical advantage with a piece of something and the crazy glue. I hope I can explain well enough.

Have a piece of "bar" longer than the case back, that it extends over the "pry" position and the opposite side. If you can give yourself some overhang on the side away from the pry point.

Add the super glue just to the area nearest the pry point, not over the whole case back. The glue should have enough bond strength and the bar enough leverage now over the total back of the case. Once the case back "pops" off you should be able then to release the bar from its bond by prying it at the far side, since there isn't any glue there. You can then get most, if not all the glue residue off, w/a razor blade. You might need to finish with Nail polish remover.    

Good luck

[dapellegrini]

The Seiko S-280 arrived today, and it was very quickly determined that it would not be of any help with this project. The tip is just too large to catch this case back. I will put a couple photos of that at the bottom of this post.

So having disqualified the S-280, I broke out the Gorilla Glue, and found a small throw-away wrench that must have come with some flat pack furniture or similar.



Being very careful, I applied some glue to the case back - then pressed the wrench on there for 15-30 seconds.



Well, I thought I was being careful. Some of the glue got down into the hatch threading, but didn't spill into the module - so it should still clean up just fine.



After letting it sit a few minutes, and with the case face down - I gripped the wrench with one hand on each side, using my thumbs against the underside of the lugs, and applied what seemed like a lot of pressure. Ends up those lugs are very uncomfortable to press your thumbs against with any force. After a few hard pushes the glue gave up - wrench and case back again separated.

So, I put more glue over the spot, pressed the wrench back on again for 15-30 seconds and again let it sit for a few minutes. This time I reversed my strategy. Using a case vice, I flipped it so the case was facing up, using the vice pegs to push up on the back of the lugs, I then pushed down on the wrench - equal pressure on both side and put just about all my weight behind it. And it worked! The case case apart!





And Kroil everywhere!

I guess that stuff doesn't evaporate. You can see it splattered onto the inside of the crystal (a couple photos above) and it obviously got down to the o-ring, as it was wet, but didn't seem to help release it.

All in all, it is a pretty grimy mess...





This is the first time I have ended up with a broken gray plastic thingy (below) - I suspect the Kroil did it in - as its soft-ish and bendy, instead of hard plastic like it is supposed to be



I decided I needed to get the crystal out ASAP to get any Kroil off the dial frame - as I am hoping that will be salvageable for a future rebuild. The crystal broke with almost no pressure



Good news is that I think this dial frame is good - minor (pre-existing) damage at Caracas - but otherwise very nice.

Here's what I was left with on the case back:



And the inner gasket was completely petrified. Prying it up with a pick was hard and it just broke off in parts.







Around where the pry-point is on the case back you can see the gasket is completely fused to the case. I couldn't pry it up, so I figured I drop it in some acetone along with the case back and see if that doesn't clean it up. The ring that sits around the other side of the gasket inside the case was also etched at the same spot where the gasket had fused to the surrounding metal.





So into a shallow acetone bath it all went



The wrench was too large for the glass bowls, so I used q-tips to soak it and a razor blade to scrape off the softened glue residue.



It took about 10 minutes for the case back to start to give way. It was gooey like this for a while:



In the end I am left with a little bit or residue or etching on the polished parts of the case back - which I think will buff out easily with a cape cod cloth (at another time).



The o-ring fragment however would not come off on its own - and had no intention of easily melting away



So back to the dental pick - and it eventually gave in



After the acetone I took a soft tooth brush with warm water and soap to the two case halves.  The residue around where the o-ring is not showing any sign of letting go.  This will get a bath in the U/S machine (another day) and more manual clean-up



Oh, and here is the S-280, you can see it just is too big for this jog:

[inboost]

Wow dapellegrini, mixed emotions here. I feel bad the kroil may have damaged the plastic movement ring. It's pretty gentle stuff usually so it's unexpected to me that this happened to you. I'm happy you managed to get it all apart though, that's really fortunate that the dial frame came out so well all things considered. It's amazing how tough that bite is between the seal and the case parts. I wonder if there might be something going on there with a third component in the mix to create this situation. I say this becuase it seems only a section of that gasket was really what was holding the whole thing back. The kroil went past most of it as it should, but not the small section you had to dig out. I bet that is what was holding the whole thing together. It's weird that it's opposite the pushers where something might enter. I wonder what it could be?

[dapellegrini]

I'm not worried about the broken gray plastic bit - I have a lot more of those.  It could have been the penetrating oil I put on it before the Kroil - not sure.  Anyhow, I saw a service mark on the case back - will get a better photo tomorrow.  I am also intrigued by how that could get sooo stuck - but I know this is not uncommon.  It is very odd that the stuck part in this case was on the opposite side of the pushers.  I will do a little more reflecting tomorrow and post an update.