Stuck brass movement ring

[fixermole]

I have a brass movement ring stuck tight. Does anyone have experience removing such with care?

It's in a old Buren auto with a Durowe 611. You can tell the ring may have been beaten in by the dimples on the top edge. I've tried to gently pry it out all around but it is soft brass. I've tried to tap around its circumference inwards to dislodge it from the case. It's pretty dirty and it does seem to be more stuck to the case than the movement itself.

I've also tried to pry it away using the stem slot, which does have a inner lip, but to no avail. I'm worried about pressing too much on the movement itself. This is the first brass one I've come across.

If it was more stuck to the movement than the case I would just apply heat to expand it, but that likely won't work for brass on brass. Would some release agent be next to try? If so, which?

Thanks in advance for any suggestions or experiences.

[Tudor]

I don’t like that the movement is there, but you could try inverting a can of “air” to release the cold liquid onto the ring and shrink it away from the case. 
 

once it’s out, address the tight fit. Either it’s out of round or oversized. 

[rodabod]

You could lift the crystal out and press on the dial with a nylon cup. Sounds extreme, but I've had to do that before.

[HectorLooi]

I think this is a front loader. There are 2 screw holes near the edge of the movement that suggests that there were movement retaining screws.

[watchweasol]

Hi I would try the cold air method first or use plumbers freezing spray to try and contract the brass ring  if none available put it in the freezer for a while.  But before all that checkout Hectors assumption, It well may be a front loader as the vacant screw holes are suggestive of such. 

[fixermole]

Thanks all for the suggestions. I'll first try contracting the ring with a can of compressed electronics duster and/or the freezer. If still stuck in there, I'll just remove the crystal to make sure it's not a front loader although there are a couple of indications it's not. I'll definitely address the fit once it's all cleaned up.

[fixermole]

All, indeed this is a front loader. It's apparent once it's apart from the case tube extending into the "movement ring". Thanks again for the advice.

 

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