Well we have all bought vostok with a broken mainspring well I have and I have changed a couple with mixed results I did see a thread once some where with lovely pic's and everything, and was quite a good read and well presented. on a russian forum some where can't remember where
But as I ant got a broken vostok to hand or the time to take loads of shots and what not
I will just list how to do it in steps as I say if I get one that needs to be swapped might take some pics then and edit or redo the thread then maybe or just add them in to a reply post with the opening bit modified ..
OK then here goes :
1) so to be sure to have let it run down i.e not ticking.
2) then with a back removing tool remove the back ring and plate and o-ring and put safely to one side...
3) on the movement there is a dimple by the ratchet and the smaller cog on the back , once you have unscrew the crown ( if you have not done this all ready ) press the dimple gentle does not need a lot of force and firm pull out the stem/crown.. place safely to one side.
4) now the movement is loose carefully take out and put into a movement holder or what every you are using ...
5) now I will try and describe this as best I can first remove the screw holding the ratchet cog it is the big cog of the three close together and place the screw and cog to one side.
6) now there are three screw holding the winding bridge (I think they call it) so remove all 3 screws. and put to one side ( it would be a good idea to have a small container with spaces for each step to keep them separate)
7) OK this bit is slightly tricky lift up the winding bridge gently holding it, you don't want to remove it just gently hold up so you can get at and get out the mainspring barrel.
At this point the broken mainspring barrel is removed it depends now what you are going to do in the thread it went on to open the barrel and removing the spring and find where the break is and possible depend where the brake is re-work the end,after the break good option. if not having a spare barrel & spring.
For this thread we are going to assume we have bought a none working job lot so have lots of parts to play with and practice on ..if you have then you will have had one shot at this when removing it from the donor ( good to give it a try on the donor just to see how it goes too).
8) so now we fit the new barrel the same as above just lift it enough to slide the barrel in, then fit the 3 screw back in and then the ratchet wheel on.. then simple you just work backwards from point 7) upwards really then once the back is on.
wind as normal and hoping it was a good donor mainspring you should have a happy vostok and a happy you
I hope I explained it well. as I say if I can get the time and a movement I might strip it down and take some pic's as I do from 3 to 7 on my list.
As always Ismy