Section 28 Fuellube & Fuel Fittings

[John-G]

Let me start by saying Happy New Years!! ... and my question does NOT refer to the NPT threads on the fuel fittings (which I know require a more robust thread sealant than Fuellube).

Section 5 suggests that the aluminum tubing?s flares should be lubed with Fuellube prior to assembly ? which sounds like a good idea to help prevent galling should the fittings twist a little during tightening or loosening.

My question ? is it acceptable to ALSO place a thin coating of Fuellube on the threads of the fittings to help prevent galling the threads (perhaps corrosion too) when tightening/loosening the AN818 aluminum fittings ? or should the threads definitely be left dry?

 

[rvbuilder2002]

The current section 5 suggests a small amount of light oil can be used (no mention of fuel lube), but if the flair is properly made it should not be necessary.
Lube on the B nut threads is not usually recommended. Particularly if you are using a torque wrench to tighten... it would cause you to over tighten if you used the standard torque values.
The best installation practice is to make sure you have proper alignment so that you can easily and fully thread the B nut on with your fingers and then complete the tightening with a wrench, double wrenching (a wrench on the B nut and one on the fitting it is being attached too) when appropriate.