Fuel Replacing the Plastic Factory Fuel Line Push on Connectors


lube between the nut and the face
Founding Member
Oct 28, 2001
Claremore, OK
I am by no means taking credit for any of this but I could not find where it was all in one place. Mustang5L5 had a thread over on the Corral about installing a 94-97 fuel pump hanger in a Fox tank but the issue is the supply line on the 94-97 unit is 3/8" and not 5/16" so the factory plastic line from the hanger supply to the inline filter could not be used. Not sure what Mustang5L5 ended up doing but he did link this video where a guy shows how to install the fittings without heat or hot water:

View: https://youtu.be/V7UzCvZTbJI

Within the comments on the video a guy posted a link on how to do this in the car and it seems to work pretty well and would work outside the car if you do not have a vise. I am going to cut and paste it here as I hate linking other forums as they could disappear and the information with it. So this is from LS1tech.com and the member that posted it goes by 1936 LS1 (I put the pictures in the thread where I thought they made the most sense as they were just at the bottom of his):

As promised, here’s a step-by-step on how to install fittings on factory-style nylon fuel line WITHOUT having to buy the expensive (IMO) tool that Dorman sells.

Here’s what you’ll need:
A roll of tubing (Dorman 800-072 is the 3/8”)
The appropriate fittings for your job
Some light lubricant (I used hydraulic jack oil)
The line clamp from a brake line flaring kit (don’t worry if you don’t have this, there’s an alternative)
A caulking gun
A single edge razor blade or tubing cutter that used for air line (gotta be something that won’t crush as it cuts)

To start, make a clean cut of the tubing. I used a single edge razor blade.
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Next, insert the end of the tubing through the end of the caulk gun as shown.

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Now, clamp the tubing in the flaring tool clamp using the hole in the clamp that corresponds with the size of your tubing. Leave only enough tubing sticking out to fit all the way on to the fitting (I've actually got a little too much sticking out in my pic). Clamp it tightly, but only hand tight. It won’t slip. You don’t need it as tight as is required when flaring brake lines. If you’ve done that job, you know what I’m talking about.
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Now seat the clamp in the far end of the caulk gun as shown. Be mindful of the tubing past the clamp. Don’t let it get any pressure on it and get kinked.
Now add a little light lubricant to the fitting. Just enough to get it shiny, it doesn’t need to be dripping wet.
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Great, now it’s time to assemble! Move the plunger forward in the gun until there’s just enough room for the fitting between the plunger and the tubing. Align the fitting with the end of the tubing and hold them in alignment with your fingers while you start to squeeze the handle of the caulk gun.

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Watch closely because it only takes 2-3 clicks to seat the fitting fully.
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Take the clamp off of your tubing and you’re ready to move on to the next one!
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Alternative clamping method
If you don’t have a flaring tool clamp there is another option. I’ve seen this a couple of places online but haven’t built one myself.
You’ll need:
a short (4-6”) 2X4 (or two 1X4s the same length)
a band saw or access to one
4 – 1.5” wood screws

Drill bits slightly smaller than your tubing OD (outside diameter) (ex. 5/16” hole for 3/8” tubing)

I got the pic of this type clamp below from another site so to give credit where it’s due, here’s the link...


That poster actually oversized one end so the fitting would go down in there too.

You can see how to build it from the pics. You could also use 2 1X4’s screwed together and drill the hole on the seam where they meet. If doing more than one size line, you could put two different size holes in one clamp.

EDIT: I added two more pics. There were some negative comments made about the way the joint in the first set of pics I took ended up so, to show that they got better after my first attempt I added a couple of pics. The tubing clamp does leave marks on the outside of the tubing but apparently the Dorman tool does as well. The wooden clamp probably wouldn't. The marks are superficial and have no effect on the integrity of the tubing.

Fuel Line Holder he built:


I found another DIY video that had another way to do it:

View: https://youtu.be/xFCQccnuvl4


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Reason I posted this as I am thinking about ditching the 5/16 and 1/4 lines on my Coupe and running 3/8" fuel line for the feel and return as that will more than will work for current engine needs plus some. Doing it this way seems like it will be very cost effective and will allow me to get the Pro-M fuel hanger. I cannot get hard lines back in the car in one piece due to the subfram connectors and braided line that is ethanol tolerant it really high dollar right now. I figure if all the new cars are running this stuff it should be just fine. Anyone have opinions or experiences that would day otherwise?
I'm trying to understand the point.
I'm not saying i'm for it or against it, i just don't understand why someone would need or want to do it.

I don't even understand the pro m fuel hanger, isn't it like $180 without a pump?
Original post was for anyone needing to just replace a fitting. My second post is just me looking at more flow rate on the existing fuel system as I am approaching the limits of the factory 5/16" feel line and the 1/4" return. Not sure if I will do it or not but this presented another avenue over dumping hundreds of dollars on PTFE braided line and fittings.
I used push lock and it wan't that bad pricewise and has a somewhat oem look.
For the pump there is always the aeromotive or holley 12-347 that comes ready to drop in and add fittings.
I've never understood that pro m hanger at that price.
I already have the pump so for me its is looking at getting more fuel out under high load conditions and more fuel back to the tank under low load or idle conditions. The Pro-M hanger is stupid on the cost but I do not think they are catering to the masses on this one.

Which push lock system did you use?
I'm pretty sure it was all earl's push loc in black, but not the glossy black.
Easy to use, not so flashy, cost effective.

Currently i use a hanger similar to the pro m, but with no pump on it, the pumps are external.
But i did it a long time ago, going to swap it to a 12-347.
I really don't like 2 pumps and not sure how i feel about the style pick up i have.
But there were no truly hi flo hangers with pumps on them back then.
Finished the layout so including the Pro-M hanger it would run me about $400 to upgrade to AN-6 feed and return lines from the tank to the fuel rails using the OEM stuff. Might try this later down the road but I have enough on my plate with the car right now.
The plastic tubing will work and can be molded to form around obstacles. Function of a hard line but less weight and actually more durable. You're giving me ideas. :chin
Assuming you used hose and not plastic line then?
Yeah it was hose.
I looked for it online but maybe it's the pics or they changed it slightly.
It has a slightly hard textured outer coating. Not easily damaged for sure.
Planned right it doesn't take that many fittings and from what i can tell it's not as expensive as it used to be.

Personally i find what I prefer these days, then search for the best price on that product.
I guess the materials in that video work, but that setup is not for me all the way to the tank.
It would be one of those cases i saved a few dollars, then spent way more to undo it later.

Edit: As i look a bit into it, it may have been aeroquip push lock.
The hose looks like what i have.
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The only hesitation I have (which is really small) is the plastic line would need to be run between the subframe connectors and the rocker panel to keep it away from the exhaust but that area is exposed to road debris. With all of that I might look at a shield of some sort for it just in this area. The fuel lines run behind the front wheel well liner so that will protect them there. The only other area they are exposed to heat would be where the lines would transition from outside the subframe connectors to inside the rear subframe. I have had really good results using header wrap on plastic lines in this area in the past but they like to come unwrapped. It would be pretty easy to find a high temperature tube that could slide over the lines (we do this in oil & gas quite a bit) so that would be the best route. Can finish the ends with some high heat shrink tube that has the glue on the inside to keep it weather tight. Would most likely use this same approach to provide protection to the lines from the front to rear wheel. A little more research here but that would be the idea.

The plastic fuel line is ETFE which has some pretty good properties:

Extruded Tubing – ETFE tubing is adaptable to many applications because of its many improved properties over such polymers as PTFE and FEP. ETFE extruded tubing offers superior strength compared to FEP, PFA, and PTFE and also possesses very high chemical resistance. ETFE tubing provides somewhat greater stiffness but also possesses excellent impact protection. This tubing can be used to protect its contents from chemical contaminants and mechanical stresses while also providing insulating properties for electrical applications. ETFE’s mechanical properties endure at temperatures to 300 °F (148 °C). ETFE tubing can be formed into special shapes to maximize application flexibility for design requirements.

Overall most of the new cars fuel systems are completely plastic now so I don't have a lot of concerns about it.
Ah yes, i remember now. I ordered the wrong hanger and got one for an 94-97 Mustang instead of the correct Fox one. Had it all installed when i realized my mistake and didn't want to buy another hanger.

I did end up just using the Dorman 800-082 fittings and pressed it onto my existing line. I remember it was a total PITA pressing it on there. Don't recall my exact method though.

It's been fine since. I am paranoid about fuel lines on these cars, so I may go back and upgrade all my lines to 6AN for some reassurance and eliminate a lot of these plastic/rubber connections and push-to-connect fittings. I think that will be my project next winter.

That pro-M 6AN hanger is rediculously priced.
The hanger is literally the same cost as all the other parts. I called Pro-M to see if they would sell it without the "installation parts" which is the S-hose and clamps, sending unit lock ring and seal, sock filter, and the isolator that goes between the bottom of the pump and the hanger. The guy said he would not reduce the price and that is the way they come. I think they might sell a few more if they dropped the price to $149.95 gave the option to buy all that stuff for an additional cost. Even then $149.95 seems like a lot but if they are not selling hundreds a year then whoever is making them for them is not going to give them any kind of volume discount.

Regardless you are correct and the price is insane.
And here is the one with dual AN6:

Wish they had a picture of it so we could see the feed and return line routing. For both hangers I did read that feed line is 5/16" and the return line has been upgraded from 1/4" to 5/16" which is an improvement but making them both 3/8 would have been better. In the reviews one of the comments stated that the return line goes all the way to the bottom so that is also a plus.

They also offer a 10% discount on orders over $100 so that drives the cost down under $100...I think I am going to pull the trigger and order it.
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In the picture it includes their hot wire pump harness. I ordered that a few weeks ago when I rewired my pump. That alone is like $30, I'm sure you could off it on the corral.