Balance cap stone of Longines 12L - 12.68N

Hi folks,

I'm relatively new to watchmaking and learning my way through so apologies for a basic question but need your advice here 😀

I'm servicing Longines 12L (12.68N) movement which is from 1942 so the cap stones of the balance wheel don't have incabloc. What I got stuck at is the jewel under the cap stone, I removed the cap stone, and the jewel under it is installed in some kind of a spring. Is it alternative (earlier) setup for the antishock system? Should I expect similar spring on under the upper cap stone too?

Please see the pictures below. Is such a setup common in the old watches? Just curious, is there any name/reference to this spring?

I'm a bit doubtful if I should remove the spring with a jewel for cleaning or maybe it is better to clean it while it is still in place. I'm not sure if installing it back needs some kind of tool or if it is straightforward. Can you please suggest, and share your experience about how you are handling such tasks?


Many thanks in advance 😀

Thank you Archer, sounds not so complicated, will give it a try. Is it a brequet spring for shock system or something else? I guess second cap stone will have same, would you expect so?