Mamiya RB67 50mm Sekor C rattle?

[Joosep]

I got a 50mm from eBay. Marketed as "very good shape". When I invert it in my hand, I hear glass moving inside. Does not matter what aperture, shutter speed its on and if it is cocked or not. If I turn the floating element all the way to the other end, the rattle stops, for about 3-4-5 inversions, then comes back.
I already anticipated my crappy explanation skills, so I made a video. Click here to watch it.

Anyone out there with a 50mm Mamiya? This "normal"?


Thanks!

 

[sevo]

Sure it is glass? And does it still happen when the lens is mounted? All my RB lenses rattle, when not mounted to the camera. Some of the coupling levers apparently get tensioned by the breech lock, and are free to move as long as the lens is off-camera.

 

[Joosep]

Yes. I can hold all the stuff still with my hand, it still rattles. I can hear/feel it coming from the inside. And yes, it still does it when it is mounted.

And to add: It feels like it is coming more from the front than the back.