Thread sealant for gasoline.

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I finally found some made by permatex It's aviation grade. Part# 80019. Anyways, I've read how you aren't supposed to use Teflon tape on npt fittings for gasoline. I think because a small peice can get into the fuel system, but how does this pasty permatex stuff not get into the system? I mean wrapping with Teflon tape isn't hard to keep a couple threads from the end. Also what about if you need to take a fitting off? How do you clean liquid sealant off?
 
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Good questions, I have never had the need to use anything on fuel lines. All the one's I've seen relied on a small o-ring or were simply quick connect styles. Even my older vehicles prior to 1970 never leaked or had issues with their regular threaded lines.
 
Originally Posted by GMBoy
Good questions, I have never had the need to use anything on fuel lines. All the one's I've seen relied on a small o-ring or were simply quick connect styles. Even my older vehicles prior to 1970 never leaked or had issues with their regular threaded lines.




They make straight threaded fittings with an oring. I think i'd prefer the regular npt style that way I don't have to worry about a little oring getting eaten up one day and leaking.
 
I love the stuff. Dab some on the male fitting and wipe of the excess, use a rag.Wait a few minutes until it skins over, then assemble. It has to be scrubbed off your hands. If all else fails read the instructions on the tube.
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I need a take a fitting out and put a different size in and I don't it will work if the fitting I wet with gasoline. I guess I could wait for it to evaporate.... Do you pull the old stuff out or do you just add more and fit in on again?
 
The stuff is non- hardening, Wipe off the old stuff spread on more, re-make the connection. I have never had any issues using it. In fact I use it any where a bolt passes through or into cast aluminum to stop the bonding
 
Never have seen tapered pipe fitting used on fuel lines. The vehicles I was around when I was a kid used inverted flare fittings. They were reliable if not over tightened.
 
Originally Posted by Yah-Tah-Hey
Never have seen tapered pipe fitting used on fuel lines. The vehicles I was around when I was a kid used inverted flare fittings. They were reliable if not over tightened.


I looked them up on the web. Looks like the male end is npt and the female side is a straight flare fitting? You would think living in Houston I should be able to drive down the street and find the correct fittings. I'm sure fuel fittings are special in some way to handle gasoline. Or is brass brass?
 
Okay this stuff is goopy and messy. Are you still supposed to apply it a couple threads back away from the end of the fitting cause I couldn't be that precise with it. I just rubbed a thin coat around the threads. It said to apply on both pieces that you're assembling.
 
It doesn't give any instructions other than let it dry a few minutes before assembling. When can you run gasoline through it?
 
Originally Posted by ledslinger
Gasoila E-Seal


When it says gas they're referring to natural gas I believe. Not gasoline. I made this mistake too buying yellow Teflon tape thinking it was compatible for gasoline.
 
Mk378 they make all kinds of liquid type sealants, but I haven't found any tape style sealant for gasoline. It's annoying because you have to wait a certain amount of time before you can put fluid through.
 
All PTFE tape is chemically compatible with gasoline. The only difference with the different tapes is the thickness and the color.

But, never use any sort of tape on a fuel system because little flecks of tape do come off when the joint is tightened, and they can get stuck in your carb float valve, jets or fuel injectors to cause malfunction.
 
Wherever you got the "keep it two threads back", that's a bad idea because you lose the sealing potential of those threads.

The real problem with shards of PTFE is they go everywhere when it is taken apart. And you did say that this application (whatever it is) would involve periodic taking apart.
 
Only time I've seen pipe dope or sealant on fuel fittings was diesels or small engines. All the flare fittings and banjo bolts on the older cars I used to work on were all assembled dry. Permatex #2 and Aviation are non-drying sealants based on an organic resin and dissolved in alcohol or acetone, which are polar solvents.
 
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