The advance lever on the 120 back of my RB67 Pro S is worryingly loose. So far it is functioning just fine, I've never had problems winding and frame spacing isn't an issue but it seems like it could be a minor disaster waiting to happen. I've only had the camera a couple weeks so I can't really say if it's been getting worse over time. I'm sure there's a way to tighten it though nothing seems obvious so rather than poking around blindly I'd be happy to defer to the wisdom of anyone who might know exactly what to do here.
The should give you an idea of how loose it is.
Your suggestions are appreciated, especially if you have successfully dealt with this before.