Fuel Lines

[brotherGood]

Alright, so for the third time since I've had the car, a fuel leak is keeping me from driving the car. So, Im finally going to bite the bullet and run all new lines from the tank forward. First part of the two parter is this; will there be an issue running rubber lines up? Im told thats what they're using in shops nowadays, and it'd probably be easier to do. Second, I saw once that if you have a modified engine, upping the size may be beneficial. Now, my setup isnt too crazy, and I dont see the 360 being any more than a decent cam, maybe slight head work, headers and a 4bbl. Is there any benefit/downfall to running bigger fuel lines?

Thanks in advance.

 

[80mirada]

You will still have the standard size fuel pickup unless you plan on modifying it. I am not a fan of running that much rubber. I think most non-metal lines on modern cars are HDPE .

 

[Justwondering]

X2
I just replaced the fuel filters on two vehicles this past week. Neither had rubber lines.

All the dirt, filth, and rocky bits that fell from the lines and rails as I worked on them made me realize I don't want long runs of soft lines under the vehicle. They get a lot of abuse.

Ditto for the brakes (but that's also a heat/expansion/pressure issue).

 

[Aspen500]

Running rubber lines is a bad idea. For one, it'll cost way more than making steel lines and it's just dangerous. The rule of thumb is to keep the rubber fuel lines to 12" or less total in the entire system.

You may be OK if you use fuel injection rated hose but it's stiff and hard to work with, plus,,,,,,,,,,,not really inexpensive. That hose is made for high pressure but also as 80 Mirada said, it's HDPE which holds up to fuel and ethanol where regular fuel hose has a finite life span.
I suppose braided stainless hose would be acceptable but again, very pricey.

In other words, use steel line and keep the rubber hose to the connections at the tank, frame to fuel pump, and filter connections.

 

[Justwondering]

Aspen500,
I love the way you explain things. Easy to visualize, on target, and you provide the answer to 'why'.
Its a pleasure to read.

 

[Dr Lebaron]

And if you run ethanol, that crap hates rubber.

 

[brotherGood]

Well, that answers that..lol. Its 5/16" line, right? How much should I pick up to run new line all the way?

Thanks for the response everyone.

 

[Aspen500]

You'll have to measure but be sure to add some in case of an oops moment.
I'd GUESS three 60" lengths or metric equivalent if that's how it comes by you guys. Don't forget to pick up a couple unions to connect the ends of the line together.
Also a good idea to put a slight flare where the hose will connect. I've had luck doing half a double flare. I mean, do the first step in forming a double flare without doing the finishing step. Or,,,,,,,do a bubble ISO flare. Prevents the hose from slipping off. the clamp won't be able to go past the flare even if it comes loose.

Yes, 5/16" line. If available in NZ, try to get the copper/nickel alloy line. It bends much easier than the old standard steel line and won't rust or rot, at least not for a very long time. It lasts like stainless but is easy to work with, unlike stainless which is a female dog to deal with. It's priced in the middle of plain steel and stainless and worth the extra cost.
We've been using the copper/nickel at work for a couple years and glad we made the switch. It's DOT approved and so will most likely be your equivalent of the DOT approved "down there".
You'll be able to spot it easily because, well,,,,,,,,,,,it's got a light copper color ironically enough, lol.

 

[brotherGood]

Im not sure what I used before..probably just whichever what cheapest. Ive got no problems getting that nickel/copper line..im in Ohio.

Do I need to replace the vapor line? I mean, its just a vent..as long as it doesnt vent bad places im ok..right?

 

[Justwondering]

my lines from the canister (87 fifth) are not metal

 

[BudW]

There are three metal lines in the area, 5/16” for fuel line, ¼” for fuel return line (the small one) and vapor return line (I’m not sure of size, maybe 3/8”)(the big one).
Unless extremely modified engine, a 5/16” fuel line will be more than adequate.

The M-bodies (not sure about F or J-bodies) have a 2 piece metal fuel line. There is a small piece of rubber hose connecting the two on the R/F frame rail, just behind the R/F upper control arm. There is a (I’m guessing) 1½” by 12” metal trim piece/plate covering the fuel lines under the control arm, that needs to be removed (two 5/16” head screws) to get access to that hose.
(Note: I’m going by memory here, so don’t quote me).
If I recall correctly, the short piece of rubber hose is where the fuel vapor and fuel return lines break away from the main fuel line.

Note: I would highly encourage you to NOT use rubber hose the entire distance.
Metal line is not hard to work with, even if you have to replace the entire distance due to rust or damage.
Having a bubble on end of metal likes is very helpful – but sense our fuel lines are not under pressure, if you don’t have a bubble there, it won’t be a real big issue.
If we are talking about pressurized fuel, then a bubble flare is a must do.

BudW

 

[BudW]

my lines from the canister (87 fifth) are not metal

Are you referring to the plastic tube coming from carburetor to charcoal canister, or the metal line from fuel tank to charcoal canister?

 

[Aspen500]

Im not sure what I used before..probably just whichever what cheapest. Ive got no problems getting that nickel/copper line..im in Ohio.

Do I need to replace the vapor line? I mean, its just a vent..as long as it doesnt vent bad places im ok..right?

Sorry bud! For some reason I thought I was responding to Brucynz with the Cordoba from New Zealand. One of those days...........................

Having rubber line on the vapor side isn't that big a deal. It won't leak raw gasoline and is little to no fire danger. Still, make sure it's fuel vapor rated hose and you'll be fine. Of course, you still wouldn't want to run the vapor line in rubber all the way to the tank. Carb to canister lines would always be rubber.

 

[BudW]

Carb to canister lines would always be rubber.

Or Plastic

 

[brotherGood]

Ok. Thanks for the help everyone..

Hopefully in the next couple of weekends I can find some time to tackle this. I really wanna get the car going again..its always been this or that since the control arm busted 4 years ago now..I miss driving the stupid thing on a daily basis

 

[brotherGood]

Alright, a little update....

I finally got some time to work on the fuel lines today. I thought the issue was the feed line, so I planned on only doing that one for now, and the others when I could get on the lift. After multiple distractions, I get that done (ish..I put a patch on it to make sure I had the right line) and come time find out..that wasnt the bad one. The bad one is the one returning fuel to the tank. I tried to splice together what hose and line I had, and it didn't quite make it.

So, seeing as how I need to take a trip to the parts store anyway..should I just get more line, or is there really a point to having that extra little bit of fuel coming back?

 

[BudW]

You may be able to get by with the fuel return capped off.
The main purpose is to reduce vapor lock on hot days.

The easiest way to plug the line is to get a 2-fitting fuel filter to replace the 3-fitting fuel filter with.
Leave the short piece of hose from the 3rd fitting (unused) and insert a screw or small bolt into the hose.