M1 Carbine adjustable rear sight question

Hoping someone can help me out... While moving the peep sight aperture on the adjustable rear sight of my M1 carbine, pushing it down from the 300 yd to the 100 yard markings, the aperture came clean off its tracks, falling out the front of the sight assemebly. A small ball bearing, which I was lucky enough to find rolled out. I'm not sure how to get that ball bearing and aperture back into the sight assembly at the same time; has anyone ever attempted this and is there a trick to getting it back together? I hate to have to replace the rear sight since it was very difficult to get on in the first place. Thanks.

I have replaced the aperture once on an original carbine that had a missing aperture and I wanted to keep it as original as possible. In addition to the small ball bearing, there is a very small, very short spring that goes into the hole in the aperture before the ball bearing. If you don't have the spring, you are hosed.

It is much easier to replace the whole rear sight than put the aperture / spring / ball bearing back in place.

If you have access to a rear sight tool, replacing the rear sight is a piece of cake. What state do you live in? Put up a post and you can probably find someone near you that will help you out replacing the rear sight.

If I wasn't trying to keep a carbine original, I wouldn't ever mess with trying to replace the aperture. When I did it a couple of years ago, I needed the bravery / stupidity I now have in my 50s and the eyes I had in my 20s. I dropped the ball and spring 6 or 7 times before it finally went together. I think I got it together by sense of smell rather than sight.

Good luck.

Mike in NC