Mamiya RB67 90mm 3.8 shutter problems

[Androb]

Hello! I been reading through the internet about finding out what my problem can be. I've been unlucky so far.

The problem is a bit weird, first few times I fire the shutter of the day, it works nicely 3-4 times. Then all of a sudden it doesn't fire. It gets stuck in the cocked position and the shutter pins on the back comes loose. So I can move the pins and the shutter blades moves nicely without resistance aswell. I have to be abit aggressive with it to fire. And when it eventually fires, it just fires the timings without opening the blades. So sometimes I just hear the timing go off without any light being let in. And after a while, it just gets stuck in the cocked position with the loose pins without ever firing.

I have found a video on youtube where they take apart the lens and cleans the shutterhousing. I have done that (was a bit nervous but was succesful). The blades were clean and not sticky/oily.
I put it together again after a night with lighterfluid in it and it still malfunctions.

Any tips what this can be? It does this on and off the body.

Thanks for reading!
Best regards, Robin.

 

[shutterfinger]

https://learncamerarepair.com/product.php?product=639&category=2&secondary=22
likely worn out.

 

[Androb]

Ah ok, thanks for reply. Sucks but expected.