Thread sealant on fuel pump flare fittings?

[Charger Fan]

Read several articles on-line about using thread sealant on fuel line to fuel pump flare fittings. Didn't think you needed any with flare fittings. Are you supposed to use a sealant on the threads of the fitting?

 

[Daves69]

Maybe use copper washers....

 

[Don Frelier]

No

 

[turbine68rt]

Never used it, never needed it.

 

[moparedtn]

On the pipe threads themselves? Sure.
On the flare connections? Heck no.

 

[pnora]

No.

 

[dadsbee]

It's a flare fitting, the flare does the sealing. A drop of oil on the fittings threads, sure. Sealant, not required.

 

[WileERobby]

It's a flare fitting, the flare does the sealing. A drop of oil on the fittings threads, sure. Sealant, not required.

Exactly. You have to think what is the sealing area ? The threads are not doing the sealing. The mating surface of the flare is doing the sealing.

 

[Aron Gleason]

All I put on the threads is assembly lube.

 

[1967coronet]

A little lube on the threads prevents galled threads.
Flare stays dry to seal, do not over tighten , flares will crack.

 

[moparedtn]

A little lube on the threads prevents galled threads.
Flare stays dry to seal, do not over tighten , flares will crack.

One of those sounds that makes your heart sink a little - the cracking of a flare nut giving up.

 

[68Moparmaniac]

Not necessary, I do however, use a touch of anti-seize on the threads of brake line, fuel line flared fittings... it helps take away that pucker factor when you're cracking them loose after time and the elements have had their way on the connection.

 

[Dipstick]

It's a flare fitting, the flare does the sealing.

Except in some rare cases where the flare fails to seal, then the gaskets shown above can save the day.

 

[Charged440]

Those copper washers sound like the ticket if you have stainless lines that won't seal up.

 

[RJRENTON]

Flair fittings are designed to seal metal-to-metal. If the joint leaks, it is possible that the fitting angle is mismatched. The common fitting angle is 37-1/2° (JIC, joint industry conference or AN Army-Navy) or 45° SAE. The fittings resemble each other but are not interchangeable. If the fitting leaks, it is possible that either the fitting or tubing connection is damaged or are not compatible. A drop of lubricant in the fitting's threads is acceptable but not on the flared portion. On the pipe thread portion of the connecting fitting, my preference is a sparingly applied pipe dope or a Loctite product
If a leak has developed, it is possible that the incorrect fitting was applied. A standard flare, 45°, for normal pressures and temperatures or for high pressures and temperatures, a 37-1/2°, is used or for a high vibration application, an inverted flare joint is prefered. For example, on a 440 six barrel application, the fuel line connections at the carbs and Tee fittings are inverted flare joints using steel tubing, double flared. Copper tubing material is susceptible to "pinch off" during flaring and subsequent tightening and fatigue failure due to vibration in service. Weathehead is an excellent brand to consider, Parker-Hannifin and...there are others. Others will have differing opinions and methods....to each his own.....just my opinion of course.....
BOB RENTON