Flare Fitting Question

[Hedgehog]

For those of you who work with tubing this should be an easy answer. For me well, I don't work with tubing very often.

I'm working on a fuel line. Was plugged, but I have it figured out now. To replace it properly I need to use flair fittings. I went to m local parts place and told them I need "1/4" flair fitting nuts for a fuel line. They seemed to take for ever, but finally came up with what looked like what was needed.

The nuts went on the line properly and I surprised myself by making some very decent flairs on the tubing. The unfortunate part is the fancy blue flair fitting barb end that was going to be used to attach the flexible part going to the fuel tank and carb does NOT thread on the flair nuts. ....... whow that was not that easy to write. ...... Is it possible that the flair nuts are metric, not an English thread? Everything looks good until its obvious the threads are NOT going to work.

 

[Hedgehog]

Or is there a different thread on fuel lines and break lines?

 

[mriplaybass]

I'm not quite sure what you are doing Hedge, but I will tell you that the generic hose barb fittings that you get at the local hardware store or even parts house are probably NPT threads. I assume that you are trying to connect to a MC carb.? If I recall correctly, the fitting going into the carb, is probably NPT male, but the other end where the fuel line is connected is an inverted flare fitting. You can't thread an NPT fitting into this. You need the fitting specifically matches the inverted flare. If you are using the OEM fittings, you would need a 1/2x20 flare nut to fit into the brass fitting on your MC carb.

 

[Belizean]

Or is there a different thread on fuel lines and break lines?

HH take this with a grain of salt but I think they are different from what I remember. Seems like the flare is different maybe one is 37 degree and the other is less. You probably need standard threads and you may have metric. I'm positive someone here knows. I had to do one flare on a back brake line a long time ago and I had to borrow a flare tool because mine was a different angle

 

[Lumpy Grits]

Make sure that is not an aircraft fitting.
Automotive flare is 45*. Aircraft(AN)is 37*.
LG

 

[Hedgehog]

I asked for a fuel line flair nut and trusted that I got what I asked for. The parts store is very highly thought of here in the Tucson area. .... Before you tell me to go to NAPA, it was a family run operation, they are now owned by NAPA's parent company.

.......... Update: While typing this I though, "a picture is worth a thousand words. While taking the pictures I now see what the problem is. I tried to go directly from the flare nut to the blue conversion. I need a female flare nut to male flare nut adaptor.

 

[Lumpy Grits]

Looks like you did go to NAPA(kinda).
LG

 

[Hedgehog]

Lumpy - Exactly.

This is what I'm trying to do. This should not look like some sort of farm fix, but something neat, clean and durable. Hope the picture makes sense.

 

[Lumpy Grits]

What is the fuel line diameter you are using?
I ask, because in the picture it looks kinda small.
What you pictured(first batch)is fine.
LG

 

[Hedgehog]

The line is the stock line and yes it is relatively small at 1/4". It was plugged with tight. Fortunately the plug was right at the gas tank where the fuel pump will be spliced into the line. These old lines are plated in copper. Why do I know that? While cleaning the old accumulated gunk off the line the copper sanded off fairly easily to expose the steel line.

 

[Lumpy Grits]

1/4", is that the fuel feed to the carb?
If so-I would look at go'n to 5/16" or even 3/8" line to reduce vapor lock issues from the summer heat.
LG

 

[DaveMueller]

Try a good hardware store. Flare fittings are common plumbing items. Even the big box home improvement stores have them. If the fitting feels light (aluminum) and is anodized, it's an AN fitting. I have a bunch that are red and blue.

 

[Hedgehog]

Thank you, I should look at the hardware stores.

Lumpy - I see your point, but ALL the existing fittings, the fuel pump, the fuel tank, the carb. are sized for 1/4" line. I'm not really in a position to change everything out. ..... this isn't for the 360. It feeds a little old F-134 4 cylinder.

 

[Lumpy Grits]

The gas sold today is far more likely to V'lock in your summer heat, than the gas sold when the Jeep was built.
LG

 

[Hedgehog]

True, when this thing was built you could just drive right up to a local dinosaur and stick a hose in him. I'm going to run this for a while, if V-lock become a problem I'll upgrade the size of the line. .... B-T-W the fuel pump is only for priming.

 

[Hedgehog]

OMG - Got all the parts I needed to finish my fuel line. A little this, a couple of those, 2" of this, 3' of that and way to much money changed hands. I should have ordered an all new fuel line from Willys America.

 

[Hedgehog]

This is frustrating but at least I found an answer. The flare fittings I got were a non-standard thread. Luck is with me though, only one needs to be cut off and replaced, that one needed to be removed to shorten the fuel line anyway. It was frustrating and expensive to figure out. You would think this would be easy …… NOT.
Why is it that one thing ALWAYS leads to another. My battery box had a lot of light surface rust on it so it was removed, cleaned and painted with bed liner. BUT, removing the box revealed stress cracks in the fire wall. So, clean the area, switch to .025 wire in the MIG, spot, spot, spot, go back and repeat until done. Then while running the front fuel line the line got caught on a piece of metal. As it turns out the metal is a stress cracked piece of inner fender. More welding, I really like welding so no big deal. But it is a lesson to pay attention to, especially if you want to do a job right.

 

[hagar]

Thank you, I should look at the hardware stores.

Lumpy - I see your point, but ALL the existing fittings, the fuel pump, the fuel tank, the carb. are sized for 1/4" line. I'm not really in a position to change everything out. ..... this isn't for the 360. It feeds a little old F-134 4 cylinder.

I just don't see anyway those fuel lines are 1/4" diameter.
If they are, they are not factory.
The F134 Hurricane won't run at any speed with such small fuel line.
If they are indeed 1/4", simply changing out the brass fittings on the tank, pump and carb to 5/16" would put you back where you need to be.

Of course you would need 5/16 line and hose as well.
This shouldn't be a big deal to do.

 

[Hedgehog]

Please find a way to trust me on this, the stock lines are 1/4", all the data sheets say 1/4", see attachment. Now, the real reason for this thread was to find out about flare fitting threads so I came to the people I trust. The dirty truth is this is for my '51 Willys Wagon with a F-134 4 cylinder.

So, Hagar, in a way you win, it isn't a CJ or a military jeep.

 

[Hedgehog]

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