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Old 08-28-2011, 09:18 PM
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what do I use to seal fuel line npt fittings with?

Im workin on a carbed fuel system that Im using an aftermarket electrical can style fuel pump from autozone. Fuel pressure output of this pump is 2 to 4 psi if I remember correctly. Well every time I turn around, theres junk in the carbs needle and seat. This junk seems to be the yellow pipe tape from lowes. Im not sure if Im just dislodging leftover old tape every time I take the fittings apart or the tape is failing. I started using this tape because if I dont use it, the fittings, (brass ones purchased at lowes), leak. Are the fittings at fault here? Is there a sealant or pipe tape thats approved for fuel fittings?
Im always workin and tinkering with this 64 vw bus and this time Im putting steel braided fuel line in all the way to the dual carbs. Goal here is no fuel leaks or fires. I plan on running the fuel line from the fuel pipe out of the tank which is slightly smaller than 8mm to a fram fuel filter(hpg-1). From there it will go through the engine tin to the fuel pump and then the fuel pressure regulator and on to the dual carbs. Im just not sure if I want to continue using this tape as Im afraid that I will be digging the tape out of the needle and seat again.
Last but not least, I just read a thread that said steel braided line still has regular rubber hose in it...which degrades. Uh, my whole point of using steel braided line was to install it and forget it. Fuel line Im using is from russel and its the -4an.

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Old 08-28-2011, 10:14 PM
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Use pipe thread sealant from permatex, or regular liquid thread sealant.
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Old 08-28-2011, 10:25 PM
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"The sealant issue"

Hey i dont know about you guys, but myself, i just put in an extra electric fuel pump on my van. And after the brass fittings I purchased, i kept putting the teflon tape on wrong. so i bought the teflon paste, and it works like a charm!!! just dont put it on the first three threads from the end. you dont want to get that stuff in the fuel!!! But i guarantee that it will seal, and you can sleep comfortably!!! And it is still soft after if you decide to disconnect it!
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Old 08-28-2011, 10:31 PM
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"The sealant issue" 2

And if you use teflon tape, you have to thread it on the rite way. that happend to me with my Edlebrock Thunder Series Carb. When i put the fittings together, they would come undone. Thats why I say use teflone paste, from Napa. Thats what i use!!!
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Old 08-28-2011, 10:58 PM
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well the pipe tape I use is the yellow tape.......says its for gasoline and other petrolium products. That might be the mistake Im making is getting too close to the end of the pipe threads with the tape, that and not cleaning old tape remnants out when disconnected. I like the liquid sealant idea. My fittings have never come loose, they just leaked here and there if I didnt use sealant of some sort. I even tried tightening the **** out of some of them...still leaked. Now Im even wondering if this steel braided fuel line crap is even worth it. I was under the impression the stuff would last for years.
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Old 08-28-2011, 11:11 PM
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Over tightening fuel and hydraulic fittings can stretch the threads, and they'll leak. as far as braided line 'crap', I've used braided fuel lines from my fuel cell and pump and brake lines for years with AN fittings, no sealant, and no leaks.
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Old 08-29-2011, 09:15 AM
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Rector-Seal works well on all fittings.
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Old 08-29-2011, 11:40 AM
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Quote:
Originally Posted by fumplet
well the pipe tape I use is the yellow tape.......says its for gasoline and other petrolium products. That might be the mistake Im making is getting too close to the end of the pipe threads with the tape, that and not cleaning old tape remnants out when disconnected. I like the liquid sealant idea. My fittings have never come loose, they just leaked here and there if I didnt use sealant of some sort. I even tried tightening the **** out of some of them...still leaked. Now Im even wondering if this steel braided fuel line crap is even worth it. I was under the impression the stuff would last for years.
You are right about the left over tape caught in the female fittings as being the major cause of it getting into your carb. It's hard to get it ALL out of the threads, so use a liquid/paste sealer- never tape!

Braided/woven fuel line- as long as it's good quality- is fine to use. In fact, NHRA approves its use along w/solid metal lines for fuel systems, where they only allow 12" of uncovered rubber fuel hose- TOTAL- for the whole vehicle's fuel system.
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Old 08-29-2011, 01:12 PM
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Quote:
Originally Posted by 68NovaSS
Over tightening fuel and hydraulic fittings can stretch the threads, and they'll leak. as far as braided line 'crap', I've used braided fuel lines from my fuel cell and pump and brake lines for years with AN fittings, no sealant, and no leaks.
for years as in install it and forget it? So the stuff lasts much longer than regular rubber line and clamps? In the vw world, its recommended to change your regular rubberline fuel hose every year.
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Old 08-29-2011, 01:21 PM
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Quote:
Originally Posted by 68NovaSS
Over tightening fuel and hydraulic fittings can stretch the threads, and they'll leak. as far as braided line 'crap', I've used braided fuel lines from my fuel cell and pump and brake lines for years with AN fittings, no sealant, and no leaks.
Well, heres what I did. Assembled all the brass fittings not too tight but snug. Leaks everywhere. Tightened them all a little bit over and over till they were real tight. leaks never stopped. So, it didnt really matter how tight they were.
I didnt know they made -an adapters to accept steel fuel line. Not sure how those hold up. Thats what I started to do was use steel fuel line. I used brass compression fittings and those leaked too. Especially when I used the ferrels that came with the fittings from lowes.

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Old 08-29-2011, 02:35 PM
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"The sealant issue" 3

Well it seems like you might have to start over, my friend. You sure not too much pressure is coming though? And the fittings might be messed up now! Did you try the paste???
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Old 08-29-2011, 02:37 PM
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I'm thinking maybe the thread angle is different on -AN fittings over NPT or SAE threads, but I have no leakage. I don't know how long to expect the braided lines to last, I think ethanol would take it's toll over time. I know in my boat I add Stabil ethanol additive to neutralize it.

-AN fittings are really nice, it takes some patience and practice to cut make up the lines, and definitely use aluminum wrenches on them to save the coating.

I've never used compression fittings on pressure lines, I double flare mine from the pressure regulator/distribution block to both carbs without problems.
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Old 08-29-2011, 03:31 PM
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Quote:
Originally Posted by fumplet
Well, heres what I did. Assembled all the brass fittings not too tight but snug. Leaks everywhere. Tightened them all a little bit over and over till they were real tight. leaks never stopped. So, it didnt really matter how tight they were.
I didnt know they made -an adapters to accept steel fuel line. Not sure how those hold up. Thats what I started to do was use steel fuel line. I used brass compression fittings and those leaked too. Especially when I used the ferrels that came with the fittings from lowes.
A properly formed double flare on the tubing combined w/an inverted flare fitting will seal fine. As will AN-type fittings. A NPT fitting should, too- so I'm not sure what your problem is.

Teflon tape/paste is a requirement for a NPT fitting because it acts as a lubricant as well as helps seal the joint. It should be used the first time the joint is assembled, or else the brass can gall. It's not needed or wanted on an inverted flare or AN-type fitting/nut.

Even though using NPT or invert flare fittings (not compression fittings, like 68NovaSS said above) from a hardware store should work together OK, you'd almost certainly do better using Russel or Earls fittings and hoses. Stay w/one brand, don't mix and match. The initial cost is a lot higher- but what's the cost of replacing your ride if it burns to the ground?
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Old 08-30-2011, 12:33 AM
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I thought teflon tape would dissolve with gasoline. If it doesnt then I will use that.
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Old 08-30-2011, 06:49 AM
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Quote:
Originally Posted by fumplet
I thought teflon tape would dissolve with gasoline. If it doesnt then I will use that.
DO NOT USE TEFLON TAPE!!! I might not have been clear on that earlier. Strings of it remain up inside the female fittings and every time the joint is disassembled it ALL has to be pulled back out of the threads, and you'll rarely get it all out.

Use paste/liquid sealant.
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