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what is this fitting - diesel fuel line leak


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Does anyone recognize the yellow circled fitting? It leads from the fuel tank to the primary filter and has a slow drip right at the red line. I'm new to diesel motors. It looks like I could put a wrench on each side and tighten to eliminate the drip. I'm worried about breaking something. Maybe there's a better way to do it? Maybe it needs replacing?

Thanks! 

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JIC female thread to hose barb.

You could take off the 2 pieces back to the valve and use a pipe thread to hose barb fitting single fitting. (With proper sealant or tape rated for fuel on the threads)

Here's the fitting on the valve side of the red line, left side is the leaking side, try tightening them, may stop the leak, may not.

 

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^^^Some one used two fittings where one would do the job. From the close fit of the two parts, I'd guess there is a flare joint under that red line. Judging by the round fuel tank, it's an old powerboat, & probably had copper fuel lines originally

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Thanks Sea Level. Google suggests Permatex thread sealant. Back it off a bit, paint it up with sealant, tighten it back down. Does this seem right?

Longy, I'm not sure what a flare joint is? Can confirm she is older (nearly 50) but she most definitely sails. 

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Backing off the leaky fitting won't do it, residual fuel on the threads will prevent sealant from working.

You shouldn't need sealant on jic fitting threads,  normally the machined faces will seal to several thousand psi, but if one of the faces gets a scratch, they leak.

 

 

 

 

 

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It's worth taking it apart at the red line to see what you've got.  Consensus seems to be a flare connection, but there are other possibilities, such as BSP (inverted flare) or even just a pipe thread.  Whatever it is, there is at least a decent chance that the two parts aren't proper mates, such as an AN into an SAE flare or vice versa, or a tapered pipe thread into a straight one.  Identification can be tricky; you need a thread gauge and calipers and maybe the little tools that Aeroquip used to sell to identify flare angles.  Also, see Pegasus Auto Racing Supplies website for useful information.  If you don't have mating parts, the solution is obvious, but if you do, a clean up and re-tightening should suffice.  Unless you have tapered pipe threads, no sealant is called for.

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The seal on those fittings is from the mating surfaces, permatex should not be used.  Open it up and inspect the surfaces, clean and reseat them.  If it still leaks, replace it.  It’s short money to stop a leak.

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