Have you had an issue before with these fittings vibrating loose?

O-ring fittings are typically not subject to vibration loosening, because they are almost always mounted to hard lines or thin brackets which damp the actual vibration applied to the connection, and the o-ring itself provides a nylock-like aid to vibration loosening resistance.

thanks, SGG

no history of vibrating loose but i since it is mounted to hard piping lines which can vibrate i wanted to see if there was an "insurance factor" in the form of a thread locker / vibratite that could be added

We normally use a thread lubricant prior to torqueing, not an adhesive like Loctite 243.

NOOOOO, please don't do this. The Loctite products are acrylic plastics and don't have the resilience of rubber. If they get on the o-ring they remove all benefits of rubber and substitute all problems of plastic. And for a cherry on top they make it a PITA to repair when it does leak.

When working with SAE products remember that they were designed for on vehicle use which includes vibration resistance. They were not designed for shadetree repair where unknown products get slathered all over the engineered system.

Normal tightening should not need 'insurance' for o-ring fittings. Unless the connected plumbing all comes loose, the fittings stay tight.

Ted

Thanks All!

So, if properly torqued to spec that's all that's needed.