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I ran a new hard line from the Fuel Pump to the carb and the lower flange is still “weeping” a bit, even after I reset and tightened it. (Photo is before when I was in the process).
I don’t want to keep torquing down on it, but it shouldn’t leak - at all. What are some things I can try?
update: Fixed!
put a little anti-seize on the threads and flare and torqued it a few times - no more leak. Thank you!
Is it leaking out of the flare, or the threaded elbow?
Stainless line?
Those sealing gaskets above might work well with Stainless. Otherwise, lossen back off. Then retighten.
make certain your using a flair nut wrench so you can get appropriate torque on it.
FWIW- the last car i did new stainless lines on, the kit i purchased recommended installing/loosening the new lines 3 times at each fitting to ensure a good seal.
PTFE Tape! Put a couple of turns on each thread and re-tighten.
The theory says it shouldn't work, but trust me, it does.
If it doesn't, then you may have a damaged line, as mentioned.
If it's stupid but it works, it isn't stupid?
I suspect that this works because:
1. You are undoing it, and redoing it.
2. The teflon tape lubricates the threads, and lets you get more pressure on the tapered sealing surface for the same amount of torque. Many ARP bolts work this way, too.
FWIW- the last car i did new stainless lines on, the kit i purchased recommended installing/loosening the new lines 3 times at each fitting to ensure a good seal.
Yes, and you may need to do it more than 3 times. A little anti sieze on the threads helps also.
I did this recently and as Sunflower 1972 says, read Lars post on the link he gave. I had to remove the pipe and bend it slightly several times to get it, so that you could tighten both nuts fully by hand and then it didn't leak.
..........Even though it works, I wouldn't recommend it.
I confess I was doubtful when I was told about this 25 years ago, but I've used it on the fuel filter joint and the P/S hose connections as a matter of course ever since - no massive torque required to seal either and no detrimental effects.
Lubricate the joint. If you assemble a flare joint "dry" it will "grab" and gall, and you will not be able to achieve proper torque and seal: The threads of the fittings should be lightly lubricated, as well as the back surface of the flared tube where it rides against the flare nut. By lubricating the parts this way, you will achieve a smooth, proper torque of the joint, and it will be leak-free. (Many people think that they corrected a leak by using Teflon tape: In fact, the Teflon tape did nothing more than provide "lubrication" of the threads so good torque could be achieved while shearing off shards of teflon tape into the inside of the fuel line...)
Alignment and lubrication of the threaded joints is mandatory assembly procedure for all AN flared connections and inverted flare tube joints (there's actually a MIL-Spec document that covers this topic).
I confess I was doubtful when I was told about this 25 years ago, but I've used it on the fuel filter joint and the P/S hose connections as a matter of course ever since - no massive torque required to seal either and no detrimental effects.
And I'm sure you're careful to only get it on the threads, just as I'm sure it does work. Anti-sieze might also work, or some ARP bolt lube, for the same reason. As long as the tapered seat is clean, as that's where the seal is made.
My only reason to advise against it is to keep teflon tape out of fuel and brake systems, from folks less careful than you. But if it works, it works!
If the Tube was flared properly then it should easily mate with the brass block and SEAL without excessive force. It should only require a few pounds of force to seal it off.
I don't think Teflon Tape is designed to be used with gasoline. I have never used it on a flare fitting connection. On some parts you could use watered down dish soap as a lubricant that washes off.
That makes sense. Even though this line is supposed to be OEM-fit. It isn't. As usual with any replacement part, it took some "working" to get it to line up. The part is well-made, just not a perfect fit. I'll undo-redo it a couple more times.
I did this recently and as Sunflower 1972 says, read Lars post on the link he gave. I had to remove the pipe and bend it slightly several times to get it, so that you could tighten both nuts fully by hand and then it didn't leak.
And I'm sure you're careful to only get it on the threads, just as I'm sure it does work. Anti-sieze might also work, or some ARP bolt lube, for the same reason. As long as the tapered seat is clean, as that's where the seal is made.
My only reason to advise against it is to keep teflon tape out of fuel and brake systems, from folks less careful than you. But if it works, it works!
I guess PTFE tape is a cleaner, some would say more current, way of lubricating joints. So as Lars implies, while it is not true to say that PTFE tape "corrected" a leak, it does what is required to prevent them. This from "The Complete Guide to PTFE Tape" "What is PTFE Tape?
PTFE tape is a simplistic yet highly versatile lubricating material and thread sealant. It is mainly used in ductwork and piping applications and is also known as thread seal tape and plumber's tape.
PTFE Tape for Petrol and Oil
Due to its chemical inertness, PTFE tape is resistant to both petrol and oil. Therefore, it is often used in automotive applications to seal and lubricate fuel line joints.
Plumber’s lubricating and sealing tape is designed to cope well under moderately high pressure and heat demands. This means that it is broadly suitable for use in environments where it may encounter oil, petrol, diesel and other fuels.
As with most PTFE tape applications, it is good practice to start wrapping slightly below the first line of threading, leaving one full thread circumference exposed at the insertion end of the mating joint. If any small pieces of tape are sheared off where the threads bite together, you can start your wrap a little further back from the endpoint to prevent these material scraps from entering and potentially contaminating connected tanks or fuel lines."
I suspect that this works because:
1. You are undoing it, and redoing it.
2. The teflon tape lubricates the threads, and lets you get more pressure on the tapered sealing surface for the same amount of torque. Many ARP bolts work this way, too.
Even though it works, I wouldn't recommend it.
I think it's stupid because it makes you look like an amateur and a bubba.....and everytime I see it I shake my head the same way I have been shaking it for 30+ on this, whether it works or not......it is like the Q-Jet spacer adapter deal.....epidemic.....about half of the cars I see or work on with Q-Jets have Teflon Tape on the threads....
Put two drops of oil on it.....achieves the same thing.......
From Lars:
Teflon tape is only used on pipe threads, which use the threads themselves as the sealing surface. Inverted flare joints, as well as "AN" flared joints, use contact between the flare and the mating fitting to seal the joint - not the threads.
That said, there are some things you should do with the flared joints when mating them:
Inspect the flared tube and the mating fitting to assure no cracks, damage, or scoring on the sealing flare surfaces.
When mating the fittings, make sure that the fittings can be fully mated using finger-tightening. If you have to "draw" the fittings together using a wrench, you have misalignment which must be corrected - the joint will leak if there is any misalignment, no matter how tight you tighten it.
Lubricate the joint. If you assemble a flare joint "dry" it will "grab" and gall, and you will not be able to achieve proper torque and seal: The threads of the fittings should be lightly lubricated, as well as the back surface of the flared tube where it rides against the flare nut. By lubricating the parts this way, you will achieve a smooth, proper torque of the joint, and it will be leak-free. (Many people think that they corrected a leak by using Teflon tape: In fact, the Teflon tape did nothing more than provide "lubrication" of the threads so good torque could be achieved while shearing off shards of teflon tape into the inside of the fuel line...)
Alignment and lubrication of the threaded joints is mandatory assembly procedure for all AN flared connections and inverted flare tube joints (there's actually a MIL-Spec document that covers this topic).
Another trick for stubborn flares (usually stainless) is the brass flare washers......whoever invented these is sitting on an Island somewhere laughing their *** off at us.....
I have never had to use one on a Copper/Tin/Steel line.....
03-14-2024, 12:52 AM
The Dreaded Fuel Line Leak - Fixes?
