75/1.4 w/ strange noise. Should I keep it?

[swoop]

I purchased a leica 75/1.4 onn ebay and it's in good physical and I believe mechanical condition. However when turning the f-stop ring there's a strange noise that sounds like grinding. It only happens when turning from a low to a high f-stop. The blades look perfectly fine.

Is this common? Should I keep it or return it?

 

[Benjamin Marks]

Return it. Or get an estimate for having it looked at and negotiate a partial refund. "Grinding" is not good. It should apply to stones and grains, but not precision mechanical objects.

 

[vizioneer]

Yes return it, I've had a 75 lux and there was no grinding noise in the aperture ring actuation, or anything for that matter.