zenit 3m light leak troubleshooting

Appreciate any help here. I mostly use LF/MF/dslr but have enjoyed my helios44/m39 lens on my dslr, so I decided to get the film camera to go use with it. I got a "working" Zenit 3m. It works but has a light leak. If anyone has experience with these cameras and not throwing them away when there is a little problem, a reply would be great. I would think the light leak is somewhere around the film takeup. It's missing a metal screw on the bottom plate on that end, could it leak through there? It also had some scraps of film near the light traps on the back door, wonder if any of that light-piped some light where it shouldn't have? The back is kinda loose with some felt in the light traps but nothing thick/plush.

image attached

Look at the black cloth where the light leak comes from and see is there a whitening. Due to old mechanism , the high stress area on cloth when cocked , distorts the ligh proof painting on the cloth. I think repairmen were painting it well with a pen.

If there is a missing screw , tape there and try again. One of my Leica IIIF and Zenit EM had these issues , one hole on the cloth , other the whitening.

If there is a cloth error , longer the lens looks to the light , heavier the effect.

Good luck,
Umut

Looks like a bad shutter curtain. I heartily agree w/ the notion of throwing it away (Russian cameras, grrrr). I have a Zenit 11 that has an excellent Helios M42 mount lens, but suffers from uneven exposures. I just moved on and bought a Japanese camera w/ a Copal metal shutter, and am awaiting my M42 to K mount adapter. Much smarter move in my mind than trying to fix a Zenit. Both the camera and adapter cost me ony $35, shipped. I can only imagine what a CLA on the Zenit would cost, and I'd bet any amount of money that when it came back it wouldn't function correctly. Life is too short!