Recently I had the issue with my Contax RX, when the mirror hit the lens’ rear part during several exposures.
After investigating on the web, I found this a common issue with contax cameras. The glue, fixing the mirror on the mirror carrier, gets loose over the years. Thus, as the camera is usually standing upright and the mirror is then on a slope, the mirror drifts downwards.
I found a nice solution on the web, using a hair dryer and some superglue.
After heating the mirror around a minute or so … very carefully moving the dryer back and forth, as the camera gets quite hot … I could move the mirror back into it’s correct position.
Finaly I put some superglue onto the edge between mirror and mirror-carrier.
Up to now, it fits ;)
P.S. Full Story here on Digicamclub.