Gasoline leakage... New Lines. No more smell!

[facultyofmusic]

A few days ago I put gas into the tank and tested my fuel system by plugging off the opening that's supposed to go to the engine. I ran the pump for 30mins and couldn't find any liquid leaks, so I thought I was done. Turns out there IS leakage. So small that no detectable liquids anywhere along the line, and just big enough to fill the garage with the smell of gasoline overnight. I bought a gasoline leak detector to pin-point where the leakage is, and I need some help figuring out what's going on. I created a separate post for this here because this is becoming bigger than "just another build thread update".

Places I've probed and verified to be NOT leaking:
Fuel vapour canister. canister.jpg
NPT fittings at the fuel filter. filter_fitting.jpg filter_fitting2.jpg
Plugs and fittings at EFI pressure regulator. fuel_plug.jpg regulator_fitting.jpg regulator_fitting2.jpg
Gas cap and filler hose. gas_cap.jpg gas_cap2.jpg gas_cap3.jpg

[facultyofmusic]

hardline compression fittings. hardline_compression2.jpg hardline_compression3.jpg hardline_compression4.jpg hardline_compression.jpg
pump, sender, and filler tube seal: sender_seal.jpg tank_seal.jpg pump_seal.jpg

What IS leaking are the braided stainless steel hoses. It's not just at the fittings either, it's along the whole line. Even at the middle of the lines no where close to the fittings. The detector's readings shoots up whenever I touch the line itself.
20220303_203750.jpg 20220303_203500.jpg

I'm confused as to why this could happen. Is the leak actually at the hose-end fittings and the gasoline's just seeping through along the stainless steel webbing? This also happens at pretty much every line. I don't believe I stripped ALL my hose-end fittings...

Here are the hose-end fittings I used: https://www.summitracing.com/parts/sum-220690b
and here's the braided line I used: https://www.summitracing.com/parts/sum-230610

[hineas]

What kind of braided line are you using? Some stainless steel braided lines will allow gasoline vapors to permeate through the wall of the line.

[egchewy79]

My guess is the fittings didn’t get properly seared into the hose and it’s leaking around one of your ends, then wicking along the braided SS.

[Jeff Kleiner]

Where’d do you get the braided hose? Ten plus years ago there were a number of complaints of odors from guys using hose from Jeggs. No true liquid leakage but gasoline odor would actually permeate the rubber hose. Replacement with material from another manufacturer resolved the issue. This probably doesn’t help you other than to confirm that the phenomenon of odors without actual fluid leakage can occur.

Good luck,
Jeff

[rich grsc]

Jeff is on the money, wrong hose, it's rubber, from Summit.

[Its Bruce]

PTFE lined hose is the preferred solution for zero petrol seepage/odor, but it requires PTFE-specific fittings.

[mikeinatlanta]

Normal for cheap china hose. If you look closely at the Summit questions you will see that it is not recommended for E85. Any hose that can't take E85 also can't take E10. Make sure that any hose is alcohol rated.

You can make it better for now by running pure gasoline without ethanol.

[Alan_C]

As was said, wrong type of hose for modern fuels. Hate to say it, but you will need to replace the rubber hose with PTFE lined hose made for fuel and the pressure pressure for your system. Replace all your braided SS line and move on.

[NAZ]

If you go to PTFE SS braided hose there are some basic rules you'll need to follow to prevent issues. The first is use a conducive PTFE hose to prevent electrostatic discharge creating pin holes in the liner (see link below). Also, use the same manufacturer and model hose and fittings as there is no standard so mixing brands can cause fitment issues and leaks. This is one of those areas that shortcuts result in safety critical problems.

http://www.techafx.com/catalog/46

[Mike.Bray]

If you go to PTFE SS braided hose there are some basic rules you'll need to follow to prevent issues. The first is use a conducive PTFE hose to prevent electrostatic discharge creating pin holes in the liner (see link below). Also, use the same manufacturer and model hose and fittings as there is no standard so mixing brands can cause fitment issues and leaks. This is one of those areas that shortcuts result in safety critical problems.

http://www.techafx.com/catalog/46

Agree 100%. I've used Earl's hose and fittings for 40 years and never had an issue. For fuel lines I use this. https://www.holley.com/products/plum...arts/690006ERL

[mikeinatlanta]

Have to somewhat disagree with the others, maybe. You have spent a lot of money on fittings, so that is your starting point. If you contact Summit by phone their tech support can tell you if they have any alcohol resistant line that will fit those fittings. If they do then that's the line you should get so that you don't waste the big money on new fittings. It doesn't have to be PTFE.

[Fman]

I went with Fragola PTFE, time will tell but after 18 months I have no fuel smell or leakage. PTFE is a more bulletproof way to go, not as easy to assemble but long term supposed to be much better. Take a peek at these two videos, does a good job of explaining fuel lines and how to properly assemble PTFE AN fittings.

Also make sure and purchase your fuel line from a reputable vendor (Summit, Jegs, Motion Raceworks, etc...) so you know you are getting the real deal. Would not order on Amazon.

[Fman]

Here is video on how to assemble PTFE AN fittings.

[mikeinatlanta]

Here is video on how to assemble PTFE AN fittings.
w[/video]

The people doing that video have are mistaken. The AN refers to the threaded side of the connection, not the type of hose.

[first time builder]

Rich the web site says for gasoline for the hose he got.

[mrmustang]

Rich the web site says for gasoline for the hose he got.

The problem being, what type of gasoline, pure, unadulterated, or 10% ethanol, or E85. Not all fuel lines marked for use with "gasoline" are specific enough, and can be aromatic, thus allowing vapors, or in the case of the OP, actual fuel seepage to occur as the fuel line in question is not compatible with a modern day fuel blend. In the mid 90's and early 2K's, when the ethanol blends became more main stream, I used to respond to these same type of posts. Have not seen as many posts in regards to this as suppliers sold off their older product and replaced it with the newer, fuel blend friendly products.

Bill S.

[rich grsc]

Rich the web site says for gasoline for the hose he got.

I know, thats why I said 'wrong hose', todays fuel has ethanol in it. Plain rubber hose is going to have issues, even with just 10% ethanol.

[JohnK]

I know that regular rubber hose will eventually degrade when exposed to ethanol, but in this specific instance (if I understand correctly) the hose has only been exposed to gas for roughly 30 minutes. It doesn't seem plausible to me that a hose would degrade enough in that period of time to be seeping gas, but I could be wrong. In Daniel's specific case, I'd be more inclined to check for a mismatch between hose and fitting, or missing o-rings on the pressure regulator AN fittings, or poorly seated o-rings on the fuel pump hanger or gauge sender, or some other source of small leaks.

[NAZ]

In my experience, fuel line leaks are typically caused by:

1. Improper installation
2. Improper materials selection
3. Damage


When looking for the source of the leak on braided hose, you may be fooled into thinking you have a hose leak and not a fitting leak as fuel can wick between the hose and the braided outer sleave. A drip does not always indicate where the actual leak is coming from, it could be several inches away from the point it drips.

IMO, using a sniffer that detects VOC vapor on a braided line is a questionable tactic but if you believe you have a leaky hose, pressure test it in a bucket of water using compressed air and look for bubbles. The amount of bubbles and location may tell you more than just where it leaks.

[efnfast]

Only use Aeroquip stainless or startlite hose - the other brands like Summit, Fragola, etc. are all junk.

I did my fuel lines with Aeroquip stainless back in 2005 and they're still fine (no fuel smells, no weeping, etc.)

[facultyofmusic]

Thanks for all the great info everyone. I ordered a set of Fragola PTFE stainless steel wrapped lines as well as matching PTFE fittings from the same brand. Unfortunately I didn't see your message in time @efnfast, I guess we'll see how these lines do. I also ordered a pressure testing kit. I'll verify the integrity of the lines and fittings before I install them onto the car.

As for the lines that are currently on the car, I don't have a way to take them off without venting gasoline into my garage, so they're staying on until my new lines are ready. I hear you on the possibility of improperly installed fittings. Here are my reasons why I didn't believe that to be the case. First, there's next to 0 gasoline vapour detectable at the fittings. The readings go higher as I stay on the line itself, not at the fittings. Second: very single line is like this. I don't think I installed every fitting improperly, as I was quite careful in making sure the fittings aren't over tightened or unseated. I have line that's more than 2FT long, and the vapour leakage is just as strong in the middle of that 2FT line as it is near the fittings.

Another curious thing I noticed today: I flexed the lines a bit and was REALLY surprised at how soft they've become. I remember bending them requiring quite a bit of effort, but now they flop like a fish. Like many of you, I can't imagine the rubber getting compromised SO quickly, but I can't help but to wonder if that's indeed the case. I want to call summit racing and see if they're seeing issues with their lines. Before I do that, though, is it normal for rubber to become so soft so fast in presence of gasoline?

[efnfast]

Thanks for all the great info everyone. I ordered a set of Fragola PTFE stainless steel wrapped lines as well as matching PTFE fittings from the same brand. Unfortunately I didn't see your message in time @efnfast, I guess we'll see how these lines do. I also ordered a pressure testing kit. I'll verify the integrity of the lines and fittings before I install them onto the car.

As for the lines that are currently on the car, I don't have a way to take them off without venting gasoline into my garage, so they're staying on until my new lines are ready. I hear you on the possibility of improperly installed fittings. Here are my reasons why I didn't believe that to be the case. First, there's next to 0 gasoline vapour detectable at the fittings. The readings go higher as I stay on the line itself, not at the fittings. Second: very single line is like this. I don't think I installed every fitting improperly, as I was quite careful in making sure the fittings aren't over tightened or unseated. I have line that's more than 2FT long, and the vapour leakage is just as strong in the middle of that 2FT line as it is near the fittings.

Another curious thing I noticed today: I flexed the lines a bit and was REALLY surprised at how soft they've become. I remember bending them requiring quite a bit of effort, but now they flop like a fish. Like many of you, I can't imagine the rubber getting compromised SO quickly, but I can't help but to wonder if that's indeed the case. I want to call summit racing and see if they're seeing issues with their lines. Before I do that, though, is it normal for rubber to become so soft so fast in presence of gasoline?

If it's garbage hose, yes.

Summit is garbage hose.

I've can't begin to count how many threads I've seen across how many forums where people use garbage hose and then are surprised when it's weeping/leaking/etc. after 3-6 months of use.

[edwardb]

Personally, I wouldn't obsess about the rubber hose, why it's breaking down, why it's now more flexible, etc. The bottom line is it's well known that rubber hose breaks down over time when used with gasoline. And with the newer blends that have ethanol it's even worse. It's really unfortunate that Summit (and others...) still show rubber hose as useable for gasoline without any further guidance or disclaimers. I feel especially bad that as a new builder you had to learn about this the hard way. If you mentioned it in your build thread, I missed it. I (along with others) would have cautioned against it. You're doing the right thing to replace it. As fast it the rubber hoses appear to be breaking down. Not going to start a flame war or argument. But will just say I disagree with previous posts that suggest there's only one brand of PFTE hose and everything else is junk. That's one person's opinion. My experience is any of the mainline brands are acceptable. Including Fragola. I happen to use Eaton/Aeroquip, and have had great luck with it. Mainly I strongly recommend using hose and fittings of the same brand. I do typically stay away from the Summit house brand. More than likely it's from one of the major suppliers. But I don't know who that might be and probably where they can buy it the cheapest. I stick with brands I recognize. Pressure testing each hose as you assemble it is a good practice. I started doing that a couple builds ago. Haven't found a leaker yet. But it's a good feeling knowing that you have a good hose before installing. Good luck.

[NAZ]

OP, I've used many different brands of braided hose, both in rubber and PTFE. For PTFE I've settled on Fragola as I use so much PTFE braided hose it's more practical to use one brand so I have commonality of spares in my AN fitting supplies. There are many good brands to choose from but some have a wider variety of fitting types making it easier to design a supply system. I've never had a problem with Fragola over the years and I make a lot of AN hoses, from -4 to -24.

The PTFE hose is more difficult to work with but pay attention to the details and with practice you'll find it becomes easier. Buy the correct tools for working with AN hose and it makes the job easier and less likely something goes wrong with the assembly. Pressure checking your hose assemblies before installation is a good idea.

[rich grsc]

I use Fragola, have had good luck with it.

[Its Bruce]

If/when using hose clamps, be sure to select by dimension and not AN size. The PTFE dimensions are different than non-PTFE AN.

[mikeinatlanta]

I used to be diehard Fragola until last year. Was building a nitrous system using -4 all Fragola. Every PTFE line leaked. Sent photos to Fragola and they couldn't help. Finally they built the hoses for me and they leaked too. The actual hose they had in stock had an out of spec liner and they could not be made to not leak, even by Fragola. Nobody is perfect.
Had to build my system out of Earls and it is fine. Would have gone Aeroquip but had trouble finding the stock I needed. The only fittings and hose I'll trust on brake lines is Aeroquip.

[Fman]

I used to be diehard Fragola until last year. Was building a nitrous system using -4 all Fragola. Every PTFE line leaked. Sent photos to Fragola and they couldn't help. Finally they built the hoses for me and they leaked too. The actual hose they had in stock had an out of spec liner and they could not be made to not leak, even by Fragola. Nobody is perfect.
Had to build my system out of Earls and it is fine. Would have gone Aeroquip but had trouble finding the stock I needed. The only fittings and hose I'll trust on brake lines is Aeroquip.

I would say your situation was not the norm and extremely rare with a defective Fragola line, I have spoke with quite a few people using there fuel lines/fittings with no issues (including myself).

[mikeinatlanta]

I would say your situation was not the norm and extremely rare with a defective Fragola line, I have spoke with quite a few people using there fuel lines/fittings with no issues (including myself).

I agree and believed them when they said it had never happened before. Like most they immediately assumed that I wasn't putting them together correctly. What the actual issue was the PTFE liner was slightly undersized, so the crimp wasn't working correctly. They were shocked when theirs leaked too.

Point being that any brand can be an issue, which is why one should ALWAYS perform a pressure test @ at least 500psi on PTFE steel braided lines. You never know for sure until you test.

[facultyofmusic]

On pressure testing, how does one pump 500PSI into a line? The electric tire pump I have only goes up to 125PSI max.

[JohnK]

No need to pressure test fuel lines to 500PSI. 125PSI is double what a fuel line will see in service, and more than enough to identify leaks.

[NAZ]

On pressure testing, how does one pump 500PSI into a line? The electric tire pump I have only goes up to 125PSI max.

The pressure used to test a hose assembly would depend on the application pressure and of course, don't exceed the working pressure rating of the hose & fittings used. A brake hose may require a greater pressure than a low pressure fuel line. For low pressure braided SS AN style fuel lines (carb or EFI) a typical home use style air compressor provides plenty of test pressure. I like to cap one end and adapt a short piece of polyflow tube to the other and attach that to an air hose. A bucket of water will give you instant results.

If you want to make your own brake hoses (not recommended) or make fuel lines for direct injection systems, you can either purchase a hydraulic pump or use an old master cylinder to rig a home grown high pressure tester. A hyd power pack pump can also be adapted -- you just have to be creative.

[BradCraig]

In response to the Summit PTFE comments, I used their stainless braided PTFE\AN fittings and it's been rock solid. All the AN fittings worked 1st try without even a drip. I just think it comes down to preference and the "skill" of the installer.

[mikeinatlanta]

On pressure testing, how does one pump 500PSI into a line? The electric tire pump I have only goes up to 125PSI max.

I use a CO2 tank. For higher pressure lines like brakes I use nitrogen.

No need to pressure test fuel lines to 500PSI. 125PSI is double what a fuel line will see in service, and more than enough to identify leaks.

The point of pressure testing is to expose leaks and faulty hose construction. You need enough pressure to do this and 125 won't on a 3,000psi fitting, especially when dealing with hose braid that diffuses the leak. In service pressures are irrelevant.

It's fine if you don't want to test your lines and have gotten away with it (so far), but advising others to not properly test their lines based on your luck is irresponsible. I used to not test my lines either. Learned my lesson when a (not leaking) fuel line came apart, sprayed a turbo, burned the car.

EDIT: To clarify with some numbers. A 1/4" ID hose has about .05 square inches of surface area. At 125psi you will have about 6.25 pound of push on the hose end, which is nothing compared to the stresses it will have in service from normal bumps and vibrations. A 500psi test will only generate 25 pounds of push on the hose end, still not radical or out of line testing.

A 3/8" hose has about .11 square inches surface area, so 125psi will result in a 13lb push on the hose end while 500psi will generate 55lb of push. Not hard to see by the numbers which is a more appropriate test pressure. 500psi is actually minimalist for fuel lines sizes.

[JohnK]

Take a deep breath Mike.

Tests can be testing for many different things. When pressure testing for leaks, 125 psi is plenty. Don't believe me? How about the manufacturer:



Pressure testing for faulty hose construction is a type of failure testing. This is beyond the scope of "normal" pre-use validation. Failure testing typically happens near or above the rated spec of a part, so even 500 psi is insufficient on a 3000 psi fitting. If it makes you feel better, then that's great. Let's just cool it with the alarmist absolutes based on anecdotal experiences.

[mikeinatlanta]

Take a deep breath Mike.

Tests can be testing for many different things. When pressure testing for leaks, 125 psi is plenty. Don't believe me? How about the manufacturer:



Pressure testing for faulty hose construction is a type of failure testing. This is beyond the scope of "normal" pre-use validation. Failure testing typically happens near or above the rated spec of a part, so even 500 psi is insufficient on a 3000 psi fitting. If it makes you feel better, then that's great. Let's just cool it with the alarmist absolutes based on anecdotal experiences.

"Take a deep breath", really? "Alarmist", really?

You are mistaken saying that the higher pressure testing is a "failure" test. You are correct saying that failure testing is done above rated spec of the part and you are correct saying that 500 psi is insufficient for that. Both you and earls are missing a key point of "in service" pressure testing, and that is the stresses induced during normal handling and use. Only testing to 125 psi does not ensure a correctly assembled fitting, and could still be subject to in service failure.

Don't really consider Earls a credible source. Earls claimed in their video that you should pressure test to in service pressure or 125, whichever is LESS. By their account, my 15psi fuel hose for my nitrous system should be pressure tested at 15 PSI. You could hand tighten the fitting assembly and get it to not blow bubbles at 15psi, then easily pull it apart by hand with minimal force. By their account my 300psi rated dry sump return lines wouldn't even need band clamps because they see minimal pressure in service and wouldn't leak at low pressure even without the clamps. Of course common sense dictates that the fittings should be assembled correctly, and tested to verify such. The question is what pressure would accomplish this.

[JohnK]

Mike, if you don't believe me and you don't believe Earls, how about Eaton/Aeroquip?

https://www.eatonpowersource.com/con...20Fittings.pdf

Step 7. Important—Check hose for pushout by observing hose position mark. Pushout should not be evident. CLEAN, PROOF TEST TO TWICE OPERATING PRESSURE AND INSPECT ALL ASSEMBLIES.




Your assertion that service pressure, or operating pressure, doesn't matter just doesn't make sense. For a fuel line in a fuel-injection system (the context of this discussion) 125 PSI is roughly double the operating pressure and perfectly acceptable for testing for leaks.

I spent 20+ years working in Manufacturing Operations, with a good chunk of that time as a Lean Six Sigma black belt doing statistical process analysis. What most anyone will tell you is that the vast majority of failures that are discovered in the final test phase of manufacturing are due to human error. Yes, there are sometimes manufacturing or materials defects, but statistically-speaking, human error is the single largest contributor to defects. This is why so many industries adopted some version of Toyota's manufacturing philosophy, where "poke yoke" or fool-proofing manufacturing operations as much as possible is an imperative. This is why we have keyed electrical connectors that can only be assembled one way, as an example.

All of that said, the most common source of failure of an assembled braided-steel hose will be user error in improper assembly of the fitting. Testing at 125 PSI is more than sufficient to identify a fitting that was assembled improperly on a fuel line. Spending a ton of time testing for improperly made PTFE liners or defective fittings is going to be mostly non-value add. If we were talking brake lines, for example, that would be a different story. I personally would never make my own braided steel brake lines because I don't have the means of pressure-testing such a line to double its service pressure.

It's fine if you don't want to test your lines and have gotten away with it (so far), but advising others to not properly test their lines based on your luck is irresponsible.

Your recommendation above goes against all literature I've seen from most major suppliers of braided steel flex lines. If you have data to support your position please share it. Otherwise, claiming that my advise is irresponsible is alarmist.

[Fman]

I agree and believed them when they said it had never happened before. Like most they immediately assumed that I wasn't putting them together correctly. What the actual issue was the PTFE liner was slightly undersized, so the crimp wasn't working correctly. They were shocked when theirs leaked too.

Point being that any brand can be an issue, which is why one should ALWAYS perform a pressure test @ at least 500psi on PTFE steel braided lines. You never know for sure until you test.

Looks like I did my pressure test with air incorrect, went to 65 psi for 10 minutes and no air leaks. The EFi system I am using runs at 58psi. Have not had any issues with fuel leakage to this point after 2700 miles on the car now. Knock on wood hopefully my luck continues.

[facultyofmusic]

Finally, and end to this fuel like debacle. 2 days ago I received my lines, fitted them, pressure tested them to 180PSI, and swapped them in. No gasoline smell in the garage ever since. The lines I used are Fragola PTFE core stainless steel braided lines. The fittings had really good tolerance and the fittings were super solid.

I left the fuel pump on for 30mins as it pumped fuel through the loop. No leaks. I also used the VOC sniffer to sniff around the fittings and there weren't any significant trace of fuel. The fuel-pump seal now shows a higher reading than the fittings themselves, and I could only smell a tiny bit of gasoline around the fuel pump seal.

Thanks to everyone for helping me out on this. I can sleep soundly now that my fuel lines are finally done for good.