So, I just pulled off the rear most section of fuel line on my 74 F-100. To remove rust from inside of the fuel line (remember it had been open for about a year), I came up with using acetic acid solution (~25%) to solubilize the ferric oxide that may have built up on the inside of the fuel line. So I made up a solution of 25% acetic acid in water (acetic acid is not a 'strong' acid, like hydrochloric, phosphoric, or nitric) and using a funnel (and closed up one end of the fuel line with a 3/8 rubber cap), poured my solution in. Two seconds later, solution came streaming out of a decent size hole in my fuel line, right around where it has to bend to go around the axle/wheel well area.

So...I definitely need to get the steel lines from LMC Truck, I guess. They're the only ones that make a set for the 74 F-100 LongBed, I think?

 

INLINE TUBE Inline tube The brake plumbing experts LMC doesn't "make" anything, they just resell whats already available. They get their lines from either Inline or Classic tube.
I've dealt with Inline and their work is top notch.
I have a '73 F100 long bed and bought all the lines that they make for my truck. Got the stainless steel version. It's not that much more than the standard carbon steel and won't ever rust.
The lines have been installed since the picture was taken.

 

Thanks Mike!

 

one word about inline tube, though, is that they are the suppliers of, it seems, almost all the "prebent" lines for classic cars sold through all the different distributors. However, its backwards from almost every other product... sometimes its CHEAPER to buy them through a third party. I don't know why, I guess they give volume discounts, or something. But jeff's bronco graveyard has their brake kits about $40-50 cheaper than inline tube will sell them to me for, and I ordered them from JBC and they were drop shipped from inline. So you may want to shop around a bit.

Also, my rear brake line for my F150 had some weird bends on it that put the brake line out in the open, out of the frame. I bent them by hand to get the brake line in, wasn't comfortable with it hanging out like that, but I'm not sure why they did it like that. I went with inline because I wanted all stainless lines, but after having to modify the stuff I got anyway, if I was doing it over again I'd just make my own. You can buy a nice flaring tool for the cost of the inline stainless lines, and then you can do your own forever. Incidentally I did just that for my fuel line, I bought a roll of aluminum fuel line from summit, a tubing cutter, and a tubing bender, and made my own aluminum lines. They work great, they won't ever rust, and I used a hydraulic flaring tool to make little bubble flares on the end to hold the rubber lines on. My total cost for materials was under $40, including new rubber line and clamps.

 

Thanks Hasteranger,
JBC doesn't carry the fuel lines for the 74, just the 76-79. Also, LMC doesn't carry 'em either.

 

You can see from the picture I had quite a collection of lines to install. All fit great with one minor exception, and it was the fuel line. The 90 degree bend where the line goes from the crossmember to the frame rail wasn't bent quite 90 degrees. I bent it by hand and eyeball, not a big deal at all.

 

+1 on Inline. A great product with great customer service.

Even if they don't have pre-bent lines you can buy a nice line bender (I liked the snap-on line bender) and bend your own for a little cheaper. This job is made easier if you have your original lines to use as a template.

 

...or you could just buy a roll of 3/8" hardline and bend your own for about $20. It's not like it's a terribly complicated run since most of it's straight.

 

Yeah, my own fuel line is nice and straight, and then the inline tube prebent rear brake line is just all over the place, its probably half again as long as it needs to be if you straightened it out. Idk I like simple straight stuff. sometimes, like for the brake lines off the master cylinder, its nice to get prebent ones, those would be hard to make. But the rear brake line, the fuel line, both are mostly straight runs down the frame and super easy to make.