Rubber vs Steel Fuel Lines?

I've read a few threads on fuel lines and it seems that most people use steel line along the frame, then flexible (rubber, etc.) to finish the connections to the tank and/or fuel pump.

Can anyone tell me why it isn't a good idea to use rubber lines, made for fuel, the entire way and skip using any steel?

I've seen bulk fuel line at most FLAPS. I thought I'd try the 5/16 fuel line and 1/4 return line in all rubber, unless someone here convinces me it's a bad idea.

 

for me, rubber fuel hose just doesn't seem to last as long as it used to.
if it isn't rotting away on the outside, it can come apart on the inside.

I'm in the "use more steel line, less rubber" club
there are those that say long rubber runs can cause vapor lock (sounds bad)
shrug on that.
it's up to you in the end.

short lengths of hose mean less to replace when they go bad.

 

Rubber, especially when exposed to heat and environmental chemicals, rots away. Even the short lengths of hose hidden and sheltered up above the fuel tank will weather, and deteriorate. Rubber is also much more susceptible to insult by exhaust heat and road hazards.

For example, fuel filler hoses are common failure for old cars. The short lengths of rubber hose in the engine compartment should be replaced every year or two. The short lengths of hose next to the fuel filter should be replaced with the fuel filter, always. These hoses are very common cause of under-hood fires.

The short lengths of hose above the fuel tank are also above the level of fuel in the tank. The lines on the frame are not, and if they fail, they will siphon fuel out of the tank on their own.

I have seen a vehicle burn because of long rubber hoses. Not my car, not my work, but I was a witness.

Don't take a chance on a fire. Steel is cheap, and easy to work with. Steel will not fatigue from vibration. Go steel - don't take a chance on rubber lines.

 

Tim...you convinced me. Steel it is. I can't see 4 years of work going up in smoke because my rubber line decides to burst or break or whatever.

I guess I'll add to that by saying, I'll buy quality brand rubber hose rated for gasoline for the short runs that I'll need.

 

yea, you're right.
got twisted on that one

 

Use metal line. It will take more rubbing and last longer than rubber lines.

I used metal line from the tank to under the hood close to the engine. Make sure that you can reach the rubber hose from under the hood in case you need to change it. I used metal clamps (with rubber liners) to clamp the fuel line inside the frame. That will reduce vibration and the possibility of metal line being rubbed in two. This way the fuel line is protected from the sticks, rocks, and other nasty stuff that could rip a line in two.

Oh and use good quality gasoline line.

 

I just added steel lines to my to do list on my JEEP.

 

I ran steel on wifes jeep. Only rubber hoses as flexable joints. I am still concerned about the heat transfer from the exhaust.

Side note, in aviation fuel lines are (higher grade) rubber and are required to be changed every five years. Do you want to replace are the all hoses every five years?

 

Well I would like to bring up some experience I have. I think all semis use rubber hose. Now I know we are talking apples to oranges, (diesel/gas) but it seems to me more on the quality of hose one decides to purchase. The cheapest available hose will break down fast, the high quality hose will not, some times lasting 3 times longer than the cheapys. Steel line is nice, something I plan to use in the future, after everything is back together and runs the way it should. If you plan on changing to EFI you will have to change all the fittings over to match new ones, and in my book it makes more sense to run temp lines (rubber high quality) than to run steel twice because of the new fittings. You can but adapters I know, but I like the clean look.

"heat transfer" will still effect a steel line on carb engines, causes fuel to boil inside, EFI won't because it is always moving and under pressure.

If I miss understand some things, please steer me differently.

 

" Only rubber hoses as flexable joints. I am still concerned about the heat transfer from the exhaust. "

I have seen steel brake lines with coiled wire covers on the outside. I think that is for wear resistance but wouldn't that help disipate heat kind of like a radiator.
On my particllar application ( 304 v-8 ) they just don't come that closen to the exhaust.

 

One last question...are brake lines and fuel lines interchangeable?

My FLAPS has pre-cut lengths of brake lines...but not fuel lines.

 

It's the same material. Brake lines come with nuts and double flares on each end.

 

I thought it might be...but since I really don't want to do this twice I thought I'd ask.

Thanks.

 

When I built my Jeep I used 5/16 steel line, bought it bulk in a roll and bent it with a brake line bender, worked great. I have fuel injection so used the efi hose for the transitions.

 

I would have 2 concerns about to much rubber fuel line, 1 would be chafing and the other would be rot. Either one would lead to failure and gas going all over and catching fire.
I know it sounds just too simple to run a flexible line and not have to get under there with a tubing bender and bend and fit and bend and fit, but in the long run a good system rigidly mounted is going not be a safety hazard. I like to trust the stuff on the Jeep, and that means safety first.

 

FWIW, I used the hard lines from the tank over to the framerail and tig welded a/n fittings to the end and ran pushlock hose( VERY TOUGH and HIGH PRESSURE) up to the bellhousing and steel OEM line to the throttle body. I put several clamps on the hose area to eliminate rubbing. I also ran the lines down the passenger side to get away from exhaust heat. Went out to the desert recently and it was 108 out and had no issues.

 

I am at the fuel line stage on my build. I have decided to go with a steel line after reading all of the debate. However... What size line do I use?
1973 CJ5 with AMC 304 V8.
Also my tank did not have a return line if I remember correctly. Only one line leaving tank and proceeding forward. Could this be right?

 

I've read 5/16 delivery and 1/4 return (if you have the return).

If you have, or will be, replacing your sending unit in the tank it will come with a return connection. I didn't see any available that didn't have the return line anyway.

 

small rubber line rotted threw in under 4 years... I'd use steal, and I use the fuel injected hose now ( for mu short lengths), way more expensive but holds up better.