Fuel return valve slight leak - question?

[Irish Rover]

Below is a picture of the generator fuel tank return valve on my boat. Both engines have similar valves. There's a very slight leak from the generator valve when I fill the tank to the max. I'd like to remove the valve, clean it up, and do whatever's necessary to stop the leak. My oncern is how the valve is secured internally - I'm concerned something will fall off when I loosen it and end up in the tank. Any advice appreciated.
Edit. I see I posted the pic of the engine valve. They're identical.

 

[penberth3]

Below is a picture of the generator fuel tank return valve on my boat. Both engines have similar valves. There's a very slight leak from the generator valve when I fill the tank to the max. I'd like to remove the valve, clean it up, and do whatever's necessary to stop the leak. My oncern is how the valve is secured internally - I'm concerned something will fall off when I loosen it and end up in the tank. Any advice appreciated.View attachment 209279
Edit. I see I posted the pic of the engine valve. They're identical.

If you're unscrewing the valve from the 90 degree elbow there shouldn't be any loose parts anywhere.

You haven't said where the leak is. There appears to be dark red sealer on the threads?

 

[Irish Rover]

If you're unscrewing the valve from the 90 degree elbow there shouldn't be any loose parts anywhere.

You haven't said where the leak is. There appears to be dark red sealer on the threads?

Thanks. I suppose technically it's not the valve that's leaking. The leak is from the part attached to the tank but I'm not certain exactly where from. By the time I got to it, it was already slightly wet and it only happens when the tank is completely full or almost full and sloshing around in a bit of weather.

 

[Boater Sam]

Get it totally dry and install small collars made from twisted blue hand roll paper tight around every joint. You will see which is leaking, there could be more than one. Or smother talc all over the joints, the diesel will stain it. I would not attempt any tightening of the square unions in the tank or their lock nuts. Changing the ball valves would be easy.
Is there an access port into the tank?

 

[Irish Rover]

Get it totally dry and install small collars made from twisted blue hand roll paper tight around every joint. You will see which is leaking, there could be more than one. Or smother talc all over the joints, the diesel will stain it. I would not attempt any tightening of the square unions in the tank or their lock nuts. Changing the ball valves would be easy.
Is there an access port into the tank?

No access port. I don't want to tighten anything right now. I want to loosen, remove, clean, reseal the square part, but I want to be sure nothing from inside will be set free to drop.

 

[Boater Sam]

Are you sure it is the square part that is leaking?
But are you sure where it is leaking?