question on how to open Grand Lange 1 rep

[myaz 3]

 I need to access the dial of one of Robert's Grand lange 1 reps to reglue the date window frame

 

I am unable to remove the movement the usual way (lift it out the back after removing the stem) as it is wider all around (see A) than the diameter of the case (at B),  i.e,  it seems to to fit below the narrower rim of the case

I wonder if the crystal/bezel assembly doesn't unscrew from the top like it does in another of my reps, an IWC FA Jones but I am unable to remove/unscrew the crystal/bezel assembly from the top of the Lange using normal forces with sticky tape and rubber ball.

I can't find any screws in the back that hold the plated together.

It does have a line indicating there are 2 plated that are somehow held together

Thank you for any help

 

 

 

[tribefan 6,768]

I don't know jack about these, but it looks like you can get something between the lug and bezel and pop it open. You can try unscrewing the bezel if it is threaded, but my guess is press fit.

[myaz 3]

Thanks.  Will see if brute prying forces prevail

[Horace Derwent 796]

Thanks.  Will see if brute prying forces prevail

Best of luck , i personally would be scared but you know what youre doing....

[GenTLe 1,501]

Looks like a front mounted movement with a pressure fit bezel like on my recently serviced Mido Multifort.

To open it I used one of these (trashed by the procedure):

and a watchmaker hammer to fit the blade between the case and the bezel. Going all around and finally pry it.

Take care as it may have a red gasket below (like those used in the snap-on caseback) and with an old one it is very difficult to fit back the bezel and glass. I ended up measuring the bezel and the lip on the case where the bezel was fitting and buy new ones from here: (the G36450 was the right one for the Mido): https://www.cousinsuk.com/product/red-gaskets-by-size-iso-swiss also putting quite some silicon grease on the new gasket to facilitate the re-fit.

Oh and also take care to your fingers as it's very easy to cut yourself using this method (I know something about that...)

[myaz 3]

Thanks a lot, using a hammer with a wedge and going all around makes a lot of sense. I had tried a watch case back knife with wrist pressure and got nowhere

[myaz 3]

tribefan and GenTle were right. Bezel doesn't unscrew, it's pressure mounted.

As per GenTle, I used this razor blade and hammer going gently all around.

The 2 holes in the pic below go all the way through: There's probably a specialized tool that can be inserted from the other side and pop the bezel off.

Anyways, here's the date window frame superglued back on

Thanks again guys