Seeking 'Cuda filler neck install tips

[GoodysGotaCuda]

I have my fuel tank out chasing a low fuel pressure issue and while I am at it, I am looking to fix my fuel filler neck. Since day one I have had a leak on the filler neck when the tank is completely full, it appeared to be between the grommet and the tank.

I have bought another, little more expensive "Mopar authentic restoration part" filler neck grommet to try.

• Is it advised to apply some RTV to seal the grommet to the tank?
  
• Have you ever had to seal the neck to the grommet? I think I have read to try white lithium grease here
  
• Any other pro-tips?

[RUNCHARGER]

I have never used a sealant of any sort there, the better quality grommet should do the job. Gasoline will eat most anything anyway.

[1 Wild R/T]

And gasoline definitely attacks RTV...  Hopefully the better grommet solves it, I've always lubed with WD40 & slid it together, never a problem....

[Plumcrazzy]

Some type of lube will surely help the assembly. I would not use a sealant. WD40, White Lithium, Vaseline, maybe even a dry lube like graphite. Try to use something that can be wiped away without a residue. 

[Topcat]

My first one leaked there too.

I used Vaseline since it would be gas friendly in the  system.

I brought the tank up almost tightened but slightly hanging at an angle.

Then put the tube in, tighten a little, push tube a little.
Repeat process.

No force was needed and went in fine this way.

[anlauto]

Lube yes, sealant no in my opinion

[Brads70]

I just used some Vaseline on the tube.( Challenger?) Don't use RTV it is not compatible with gas.

[GoodysGotaCuda]

Thanks for the input all! Fuel pressure is fixed, awaiting my new grommet. 


I had the pump shift in the tank and come loose, I was running at 11psi according to my logs at WOT!