Manuel,

I would say it depends on how much watch stuff you have done and how mechanically inclined you are. I have done it to some of my cal 12 watches with mixed results, some good and some not so good. It is at least reversible if you mess up, but will likely require a watchmaker.

I’m assuming you have the proper tools.

1. Remove case back.
2. Remove the stem/crown. To do this you need to turn the screw that holds it in about a quarter to half a turn and no more. If you turn it too far IT WON’T HOLD THE STEM WHEN YOU GOE TO PUT IT BACK IN.
3. Loosen the two screws that hold the movement into the case. These have a rectangular washer that you slide to side. You don't need to remove them.
4. Carefully remove the movement and set aside in safe place.
5. Tighten the loose pusher.
6. Installation is the reverse of removal.

Step two is where I have screwed up both literal and figurative. The set screw for the stem has a lever or something that attaches from the dial side of the movement. This lever is what holds the stem in place. If you unscrew the set screw too far it also comes apart from the lever and the only way to reattach it is by removing the dial and hands.

And now for the disclaimer, I’m not a watchmaker and I don’t claim to be one. So take any repairs at your own risk:)

Eddie

: Hello,

: i need some help, to fix a pusher on one of my cal. 12 watches:
:
:

: It's the reset pusher, that is a little bit loose, so you can see
: the sprocket. Can i fix this myself or is this no job for a
: rookie?

: Cheers,
: Manuel