[71 T/A]

Do you all like to use teflon tape on a factory steel line running from fuel pump to carb?
This is a Qjet on a 68 GTO.

[steve25]

No, they seal on a flange seat like Brake lines do.

If you need tape to stop a leak then either end of the flange seat is deformed or nicked, and tape will seal up the threads themselves for a while but eventually you will have a leak.

Note that you have aleak at the pump the block like projection the comes off most pumps that the line screw into has been know to split from the nut getting tightened into too much.

[TCSGTO]

Don’t use tape on fuel fittings. I’ve seen it break loose and clog carburetor passages.

[STEELCITYFIREBIRD]

No....never!!
Teflon tape and carburetors don’t play nice together.

[younggto]

If you need to use anything I’d say use High Tack gasket sealant.

[Formulajones]

Using Teflon or any kind of sealant on a flared fitting will do nothing to seal the flare. If you have a leak it's because something is wrong with the flare, the threads don't do the sealing, and when it leaks past the flare, if it doesn't come out of the threads it will just come out behind the nut between the tube and the nut.

Most of the issues I've seen with flares is using the cheap seam tubing from the auto parts stores. Sometimes they just don't flare very well, especially if using a cheap flare tool. Seamless tube is better but harder to find and more expensive, and of course a good quality flare tool does wonders.

[flat-bill]

I use just a touch of antiseize between the back side of the flare and the flare nut. This will allow the nut to tighten smoothly without galling. Some times it is necessary to tighten and loosen the flare nut several times to get the flare to seat down properly on the inverted fitting. Billk

[Schurkey]

Teflon / PTFE tape has no business anywhere on a car. Fuel and oil systems, especially. If it doesn't shred and cause problems during installation/tightening, it'll shred and cause problems when disassembled.

There are some liquid "Teflon" sealers that can be useful; but not on flared fittings.

[Greg Reid]

If fuel has gotten to the threads of a flared fitting it's already gotten past the sealing point.

[Formulajones]

Originally Posted by flat-bill

I use just a touch of antiseize between the back side of the flare and the flare nut. This will allow the nut to tighten smoothly without galling. Some times it is necessary to tighten and loosen the flare nut several times to get the flare to seat down properly on the inverted fitting. Billk

.....

[lust4speed]

Seeing Teflon tape or really any sealant on flared fittings is a Jeff Foxworthy moment -- "Here's your card..."

[steve25]

Lol! Agreed!

[Kenth]

I have found a proper copper or fiber gasket inside the inlet fitting against the cone will save the day sealing these types of lines.
No need for gorilla arms.

[Cliff R]

Another BIG problem I see a lot with this sort of thing is cutting the steel line between the fuel pump and the carb and putting rubber hose and clamps on it. BAD idea, especially if the ends of the steel lines don't get a "bulge" put on them to effectively hold the hose and clamps.

These new fuels are extremely hard on any type of rubber hose, and the last thing you want is a fuel leak under the hood on the pressure side of the system.

I've had several customers call the shop this year alone with stories of nearly burning their vehicles to the ground when they developed leaks with these new "fuel injection" systems. They are high pressure and even worse when you develop a leak someplace after the pump.......Cliff

[Formulajones]

Agree Cliff,

I just got back from Goodguys with over 2,000 cars. I can't even begin to tell you how many high dollar cars were there with rubber fuel hose up to the carb and cheap fuel filters plumbed in

I can't understand why so many people are afraid of bending a little bit of steel line and putting a couple flares on it. Everyone into classic cars at that caliber should at a minimum have a flair tool and tube bender in their tool box.

If nothing else at least go the easier (but more expensive) route and buy good AN line and fittings and plumb a nice safe system. You can at least do that without any special tools. But rubber fuel line with worm clamps? UGH! There really is no excuse for it these days, especially when all these pump to carb steel lines are even reproduced for many applications.

[11th Indian]

Teflon tape is a lubricant and not a sealer.
Nothing sexier than a preformed metal fuel line with no dents cuts or modifications...

If it leaks - it needs replacement.

[Ben M.]

Originally Posted by Formulajones

There really is no excuse for it these days, especially when all these pump to carb steel lines are even reproduced for many applications.

People who don't know me scratch their heads and people who do know me laugh and smile when they see any car I own: grimy dirty 50 year old motor, brand spanking new uncut steel fuel line from pump to carb. I don't tolerate ANY rubber that isn't where the factory put it.

I also think I've taken off teflon tape from the last 6-7 cars I've owned. The only car that I didn't need to was a low miles original '74 455. Seems the myth of "needing extra help to seal" has been around a long time.

[autobahn]

Teflon tape can be successfully used IF you know how to use it the first 2 threads CANNOT have any tape on them, and only on a tapered thread, does NOTHING for flair type joints the only thing for flair is to put a SMALL amount of oil or antiseeze on the outside portion of the flair some will poo poo this but after 50 years as a pipefitter I know what I'm talking about!ANY thing else I'm still a student

[77 TRASHCAN]

Originally Posted by Cliff R

Another BIG problem I see a lot with this sort of thing is cutting the steel line between the fuel pump and the carb and putting rubber hose and clamps on it. BAD idea, especially if the ends of the steel lines don't get a "bulge" put on them to effectively hold the hose and clamps.

These new fuels are extremely hard on any type of rubber hose, and the last thing you want is a fuel leak under the hood on the pressure side of the system.

I've had several customers call the shop this year alone with stories of nearly burning their vehicles to the ground when they developed leaks with these new "fuel injection" systems. They are high pressure and even worse when you develop a leak someplace after the pump.......Cliff

Not just cutting the factory steel line, BUT putting a clear PLASTIC drug store filter inline. You can buy metal filters. Lots in line fuel filters you'd buy came with short pieces of rubber hose and the spring clamps. They did this, because Chrysler products used this setup......from the factory...LOL

[68azbird]

use the yellow tape