What fittings do I need for fuel lines

[Groenys 57]

So I am trying to relocate the fuel tank to under the bed. My problem now is that I cant seem to get the right fittings for the fuel line. The couple auto parts stores here are no help at all. The only fitting they had was a male flare to go onto the stainless fuel line. I ordered 2 6an flare female by barb to connect the hard line to rubber line. The problem I am having is the fittings wont go together. I'm assuming the male fitting is correct because it fits on the stainless line, but the female fitting is to small to connect. I looked up and thought that 6an was 3/8? So my question is does anyone know the exact fittings I need for 3/8 stainless line? I have tried taking them in to the 2 parts stores around here and no one even has flare female fittings. Some pictures below of the fittings i currently have.

this is the male end on a piece of 3/8 line


this is the female by 3/8 barb end




this is them not going together. the male is to big.


I also don't know what the connection type is from my fuel pump. Can anyone tell from the picture?

[ndeep]

your stainless male and piece of tubing appear to be standard 45 degree double flare, not 37 degree an flare. that would be why they wont thread to each other. if you are just going to go to a barb fitting, i dont know why you just dont go from 45 flare to barb

[Groenys 57]

Originally Posted by ndeep

your stainless male and piece of tubing appear to be standard 45 degree double flare, not 37 degree an flare. that would be why they wont thread to each other. if you are just going to go to a barb fitting, i dont know why you just dont go from 45 flare to barb

Ah that makes sense why they don't go together. I didn't know they are two different degrees. So I just need to order some 45 degrees female by 3/8 barb and they will work?

[mr48chev]

I'm pretty sure that black fitting has pipe threads in it. It isn't a normal automotive fitting.

I'd have to go look in my stuff but the fitting going into the fuel pump looks like it is for a compression fitting that uses a nut and ferrule. Or it was used with a fuel hose that had an end on it that screwed on that fitting.

You should be able to unscrew that brass fitting from the fuel pump and match the threads on it to a fitting that will screw in it properly and have the correct end to slip a hose on it that also has the correct diameter passage in it. The less fittings you have the less chance for a leak you have.

[1project2many]

Ordering "45 degree flare" may not get you what you want. If you look for "3/8 female inverted flare" you're more likely to get a fitting that attaches to the nut that you currently have on the steel line.

https://www.summitracing.com/parts/edd-724660

But what is that brass fitting in the last picture? The blue convoluted cover and the fitting style look like Ford to me (and to one of the techs here). If it is, I believe you can use a high quality compression union type fitting with it.
https://www.amazon.com/Ham-Let-30020...n%3A5485702011

[e015475]

This might help

https://www.speedwaymotors.com/the-t...xplained/28780

http://www.hotrod.com/articles/0605s...tive-fittings/

[mr48chev]

I went back and read your original post and one point you fully missed is that you have to have an AN fitting to fasten an AN fitting to. They don't connect to standard fittings without an adapter.

AN fittings were designed and still used in the aircraft industry. They got adapted to hot rod use much later. Now street car guys like them because they "look cool" but most of the time aren't needed for regular street rigs. A bit of history on them plus a good explanation here. https://www.pegasusautoracing.com/do...ocID=TECH00096


NOW UPDATE after the coffee kicked in and I started looking at you photo of the pump the fitting you show is on the OUTLET side not the inlet side.
That normally is used with an inverted flair fitting and steel line running to the carb. The inlet is the tube that the short fuel hose that connects to the steel line running up the frame connects to.

[Groenys 57]

Originally Posted by 1project2many

Ordering "45 degree flare" may not get you what you want. If you look for "3/8 female inverted flare" you're more likely to get a fitting that attaches to the nut that you currently have on the steel line.

https://www.summitracing.com/parts/edd-724660

But what is that brass fitting in the last picture? The blue convoluted cover and the fitting style look like Ford to me (and to one of the techs here). If it is, I believe you can use a high quality compression union type fitting with it.
https://www.amazon.com/Ham-Let-30020...n%3A5485702011

the last picture is the fuel pump fitting. I will try that link to the inverted flare to barb and see if that works. thanks

[Groenys 57]

Originally Posted by mr48chev

I went back and read your original post and one point you fully missed is that you have to have an AN fitting to fasten an AN fitting to. They don't connect to standard fittings without an adapter.

AN fittings were designed and still used in the aircraft industry. They got adapted to hot rod use much later. Now street car guys like them because they "look cool" but most of the time aren't needed for regular street rigs. A bit of history on them plus a good explanation here. https://www.pegasusautoracing.com/do...ocID=TECH00096


NOW UPDATE after the coffee kicked in and I started looking at you photo of the pump the fitting you show is on the OUTLET side not the inlet side.
That normally is used with an inverted flair fitting and steel line running to the carb. The inlet is the tube that the short fuel hose that connects to the steel line running up the frame connects to.

The picture of the pump is what is left after I took off the hose coming from the original fuel tank.

[1project2many]

Originally Posted by Groenys 57

the last picture is the fuel pump fitting. I will try that link to the inverted flare to barb and see if that works. thanks

We have Ford vans here at the shop with fittings that look like what's on your pump. I believe compression unions work just fine with those.

[dsraven]

do you have a hydraulic hose place anywhere nearby?
if you are simply trying to get a new fuel supply line from the tank to the mechanical fuel pump you should be able to reproduce the bubble in the line to keep the hose from blowing off with a partial flare or a bead roll tool. the pump probably has a bubble style hose fitting on the inlet similar to a barb but less harsh on the hose, which should be fine with a good quality fuel line attached, such as rubber style fuel injection fuel line and fuel injection fuel hose clamps instead of gear clamps. from there you need to connect to the steel or stainless line on the frame. the problem is that line doesn't have the bubble on it, correct? what about checking with a hydraulic hose shop about getting a partial bubble flare put on the tube? google bubble flare and you will see what I mean and how it looks.
like this

https://www.youtube.com/watch?v=voP3cmakecs

or this tool

https://www.jegs.com/p/Earls/Earls-E...40092/10002/-1

the jegs tool would be a fairly inexpensive way to go and you could do as many lines as you want. I recommend the fuel injection hose and clamps though. better reinforcement in the rubber line and the clamps don't dig into the hose like a gear clamp does. if you use a fitting for anything just make sure the passage through the fitting is at least the same size as the tubing inside diameter. otherwise it becomes a restriction.
dunno if that helps

[dsraven]

a transmission shop may also be able to fix you up with some fittings that have barbs on one end and a flare style thread on the other. they are made to fit into the trans cooler port on the rad, which is usually a flared fitting. they come in a trans cooler kit so they sometimes have extra fittings laying around. the outlet of the fuel pump is likely gonna be the same thread, dunno for sure since it's been awhile since I had to replace that line. it is the pressure side of the pump so remember to use quality parts. steel line would be better than rubber in this area up to the carb.

[mr48chev]

One question, have you ever had the truck running with the lines hooked up the way they were?

I see the photo of the pump disappeared but if you never had it running before someone else may have hooked it up wrong. Could be an odd ball pump that has the inlet and outlet in different spots than normal but I rather doubt it.

[_Ogre]

before you go any further, you need to back up and show us the tank fitting
you're posting random fitting pictures and expecting someone to figure out what your doing

as mr48chev mentioned the fuel pump fitting is the outlet that hooks to the carb. you don't need any adapters, just buy a 5/16 inverted flare steel line from the parts house and bend it to fit between the pump and carb

[Groenys 57]

Originally Posted by _Ogre

before you go any further, you need to back up and show us the tank fitting
you're posting random fitting pictures and expecting someone to figure out what your doing

as mr48chev mentioned the fuel pump fitting is the outlet that hooks to the carb. you don't need any adapters, just buy a 5/16 inverted flare steel line from the parts house and bend it to fit between the pump and carb

The line to the carb is still connected in the picture. The fitting that is showing in the picture is what connects to the fuel tank line. I removed the old line that was ran. It had about 6 inches of rubber hose going from the pump to the fuel line. Then it was hard line all the way until about another 6 inches of rubber line that connected to the original tank. That is why I was trying to do it the way I was. Because I thought I read you should use rubber at the tank and the pump to give it a little flex. If that's not correct Ill be happy to figure out what the correct way is. I just want to get the pump back connected to the tank so the truck will run again.


This is the connection from the Tanks Inc fuel tank. 3/8 npt I was told.


this is the connection that I took off the fuel pump that was conected to the rubber hose.

[Groenys 57]

Originally Posted by mr48chev

One question, have you ever had the truck running with the lines hooked up the way they were?

I see the photo of the pump disappeared but if you never had it running before someone else may have hooked it up wrong. Could be an odd ball pump that has the inlet and outlet in different spots than normal but I rather doubt it.

Yes the truck ran before I removed the original fuel tank. I have not touched the line from the carb at all

[1project2many]

I kept seeing that fuel pump picture as a canister style electric pump. The blue conduit on the line next to is is what Ford uses on their diesel fuel systems and we have it on some of our gasoline powered vans. Sheesh...

You should use flexible line (hose) between the engine and steel line attached to the frame and also between the cab/tank and the steel line on the frame. Typically these hose sections are less than 6" long.

The brass fitting you are holding in your hand in the newest pictures is 3/8" inverted flare female. It is not really the correct match for the brass fitting in the pump. I would remove the brass fitting in the pump and check for a 1/4" pipe fitting. If the pump is 1/4" pipe I would use a 1/4" pipe to hose barb fitting to simplify the connection.

At the tank I would probably use a 3/8" pipe male to 1/4" pipe female bushing. Then I would use a 1/4" pipe to hose barb fitting just like at the pump. It is possible to find 3/8" pipe to hose barb but in this are it's tricky so the 1/4" pipe would be easier.

The ends of the steel tube on the frame should be flared slightly or bubbled to prevent the rubber hoses from coming off as easily. The frame line is a suction line so you could attach the hoses without a bubble and it would probably work ok but I'd make sure the bubble was there.

Good luck.

[Groenys 57]

Originally Posted by 1project2many

I kept seeing that fuel pump picture as a canister style electric pump. The blue conduit on the line next to is is what Ford uses on their diesel fuel systems and we have it on some of our gasoline powered vans. Sheesh...

You should use flexible line (hose) between the engine and steel line attached to the frame and also between the cab/tank and the steel line on the frame. Typically these hose sections are less than 6" long.

The brass fitting you are holding in your hand in the newest pictures is 3/8" inverted flare female. It is not really the correct match for the brass fitting in the pump. I would remove the brass fitting in the pump and check for a 1/4" pipe fitting. If the pump is 1/4" pipe I would use a 1/4" pipe to hose barb fitting to simplify the connection.

At the tank I would probably use a 3/8" pipe male to 1/4" pipe female bushing. Then I would use a 1/4" pipe to hose barb fitting just like at the pump. It is possible to find 3/8" pipe to hose barb but in this are it's tricky so the 1/4" pipe would be easier.

The ends of the steel tube on the frame should be flared slightly or bubbled to prevent the rubber hoses from coming off as easily. The frame line is a suction line so you could attach the hoses without a bubble and it would probably work ok but I'd make sure the bubble was there.

Good luck.

Are you saying that I don't need a connection from the stainless line to the hose connection? That's my biggest issue I have is that I cant seem to figure out how to connect the two. I have a connection for the tank side. but just couldn't figure out how to get from the hose to the stainless.

[1project2many]

No, you don't need a fitting between stainless and hose. If you expand the end of the stainless the hose won't slip off when clamped. This is how factory installation is done.

Some example shapes:






I like to make a partial flare using the bubble flare tool as it seems to give the best shape. But you can get an acceptable bubble using 45 degree inverted flare mandrels.

[Groenys 57]

Originally Posted by 1project2many

No, you don't need a fitting between stainless and hose. If you expand the end of the stainless the hose won't slip off when clamped. This is how factory installation is done.

Some example shapes:






I like to make a partial flare using the bubble flare tool as it seems to give the best shape. But you can get an acceptable bubble using 45 degree inverted flare mandrels.

Thank you. I will look into the bubble flare. I have a 45 degrees flare tool I will see what kind of bubble I can get with it.

[dsraven]

-try to keep the number of fittings to a minimum, less chance of leaks or line fatigue cracking/breaking. if using a fitting near the end of a rigid line secure the line fairly close to the fitting to keep vibration from causing fatigue cracking of the rigid line near the fitting or in the fitting

-mechanically secure the rigid line to the frame, not the body, because the body will move independent of the frame and may cause issues. this would vary for those who have the tank in the cab or attached to the body. in this case secure the rigid line to the body, from the tank to the frame, until it reaches the frame area, then use flexible line for the transition to the frame. also use flexible line to connect the rigid line on the body to the outlet of the tank

-use good quality flexible fuel line. I personally prefer the fuel injection hose because it has better cotton (or whatever they use) reinforcement and holds it's shape better. if you look at the end of a cheap fuel hose compared to the better quality hose you will see the reinforcement. some have more than others. I understand you are only dealing with a suction line from the tank to the pump so there is no pressure, but I usually go with the best stuff when it comes to fuel line and clamps etc

-use flexible line for the last 6" where the mechanically secured rigid line transitions to the fuel pump or the fuel tank. this absorbs flex and vibration but also allows a disconnect to remove a pump, a tank or an inline fuel filter

-install an inline fuel filter inline before the pump in an area that is easily accessed and not directly above a hot item, like the exhaust, or near a battery or other flammable item. mechanically secure the rigid line to the frame before and after the filter and also mechanically secure the filter to the frame using some sort of bracket and a simple gear clamp around the steel fuel filter body. this allows easy filter changes but keeps the filter secure and the filter bracket allows less strain on the rigid line from the weight of the filter full of fuel plus anything that may get hung up on the filter, road debris, mud etc. use flexible line to connect the parts

-use the fuel injection style hose clamps at the junctions if possible because they have a better clamping force than a gear style clamp and also gear clamps tend to distort the flexible line (actually draw the rubber through the holes in the clamp "gear") and can cause tears in the cotton line reinforcement if torqued up too much

-use a liquid pipe dope rather than a teflon tape style of pipe thread sealant, where needed, because the tape style can break off small sections, if the connection is ever undone, and those threads of the tape can get into the fuel system and cause havoc

-flared fittings do not need a sealant. some lube on the threads but not a sealer. the seal is mechanical between the tapered parts that contact when the fitting is tightened

-use a ground wire from the fuel filler neck near the gas cap on the tank to the frame that supports the tank, whether it is mounted to the body or the truck frame. this will eliminate the static that can build as fuel runs through the fuel lines from the gas station tank, gas station pump, gas station filler hose and handle, your truck filler neck and all the way up to your fuel tank. the same reason why aircraft fuel tenders require grounding and bonding before filling the planes and also why the sign says "remove gas cans from the vehicle before filling" at any gas station. the vehicle is sitting on rubber tires (so insulated from the ground) and your body or clothes can become the connection required to ground the static. if you check a modern vehicle fuel filler neck you will see the ground wire attached to the filler neck below the gas cap and the frame of the vehicle. below are a few examples of some filter hanger ideas and also some clamps and better reinforced fuel hose. spendy but you only need a foot or 2

http://www.tanksinc.com/index.cfm/pa...rod/prd432.htm

http://www.hrpworld.com/store/defaul...ters-each.html

http://www.hps-siliconehoses.com/hps...fuel-line.html

https://www.grainger.com/product/GAT...on-Hose-45VF25

[dsraven]

check this in post 620 for a cool and cheap idea to mount the inline fuel filter

http://67-72chevytrucks.com/vboard/s...446527&page=25

[dsraven]

tube benders like this also do a great, uniform bend. if you have many bends I suggest some sort of bender to get a good job and have things look great when done

https://www.swagelok.com/en/catalog/...part=MS-HTB-6T

[_Ogre]

adapt from the 3/8'' npt on the tank to #6AN and run steel line up the frame
rubber hose should be minimal, just from the frame to the pump
with a new tank you don't need a fuel filter before the pump, just after