Bending Fuel Lines

[jeffball610]

So I've taken on the task of bending up all new brake and fuel lines for my 510 project. I've done this for several reasons, not the least the fact that steel lines get rusty after 40 years.

 

I've bent up the brake lines without much hassle, but the fuel lines are another issue. I'm using 3/8" standard steel line and I keep crushing the bends. I'm not sure what the issue is other than perhaps using a generic tubing bender that has a max tube diameter of 3/8".

 

Is there a trick here? Should I step up to a big boy bender? The only other advice I've seen is putting sand into the line to keep it from crushing. Not sure if I want sand in my fuel lines. Any advice is welcome other than the use of braided line. I have limited space as it is and soft lines are not the answer anyway. Of course I'll be using braided line and AN fittings at junctions, so that's been covered. Let me know if anyone has advice or if there is a decent tutorial somewhere.

[DAT510]

You can try heating it. When i bent mine, i crushed it once, and that was because i didn't do it in a smooth motion. I used a cheapo bender from Autozone and it worked fine. Try bending it in one steady motion.

[DATN510]

You can try heating it. When i bent mine, i crushed it once, and that was because i didn't do it in a smooth motion. I used a cheapo bender from Autozone and it worked fine. Try bending it in one steady motion.

 

I second that process.

[bananahamuck]

Don`t heat the lines. But yeah the better the bender the easier it is to get tighter bends.

[Emptytank]

So I've taken on the task of bending up all new brake and fuel lines for my 510 project. I've done this for several reasons, not the least the fact that steel lines get rusty after 40 years.

 

I've bent up the brake lines without much hassle, but the fuel lines are another issue. I'm using 3/8" standard steel line and I keep crushing the bends. I'm not sure what the issue is other than perhaps using a generic tubing bender that has a max tube diameter of 3/8".

 

Is there a trick here? Should I step up to a big boy bender? The only other advice I've seen is putting sand into the line to keep it from crushing. Not sure if I want sand in my fuel lines. Any advice is welcome other than the use of braided line. I have limited space as it is and soft lines are not the answer anyway. Of course I'll be using braided line and AN fittings at junctions, so that's been covered. Let me know if anyone has advice or if there is a decent tutorial somewhere.

 

 

When I have to make tight bends, I will fill the line with table salt, then tape the ends shut. This media (can be sand also) will prevent kinking and works really well for bending without tools also.

[Boaty]

When I have to make tight bends, I will fill the line with table salt, then tape the ends shut. This media (can be sand also) will prevent kinking and works really well for bending without tools also.

 

Dude. That's an amazing idea, I've never heard of such a thing! Seems legit, even if you're just trolling, I'll try it anyways. Couponed the shit out of salt earlier this year, plenty to spare. Haha.

[Laecaon]

Dude. That's an amazing idea, I've never heard of such a thing! Seems legit, even if you're just trolling, I'll try it anyways. Couponed the shit out of salt earlier this year, plenty to spare. Haha.

 

It is legit, I have heard of this process before. Considering sand is like 3.99 for 50lbs at home depot, I might go that route.

[DAT510]

lol my dad just told me about this last week. my friend is trying to bend his down pipe some more and my dad recommended this.

[FoxyRoadster]

When I have to make tight bends, I will fill the line with table salt, then tape the ends shut. This media (can be sand also) will prevent kinking and works really well for bending without tools also.

 

 

I've also heard of a method of putting soapy water in lines and freezing them to bend without crushing.

[jeffball610]

So I'm finally back on my fuel line issue. I made up a little tubing "de-bender" using some timing belt pulleys and a water pump pulley to help straighten the coil of fuel line. I bent up one small section of tubing using the sand-filled method, and it works pretty good. However, now I need to bend over 110" of tubing. I can't seem to get enough sand in there.

Actually I'm using baking soda, as I figured it would be about as fine a powder I could find and it cleans up easy. I made a really small funnel out of paper and it worked okay for the small section, but trying to get this stuff in such a long tube is killing me. Anyone know of a better way to get this in the tube? Or a more reasonable way to get this done? I'd rather not make multiple sections and I'm pretty set on getting this done and not using braided line all the way back. The pros seem to be able to do this, so why can't I?

[DAT510]

stick in the ground and dig with it lol.

[DanielC]

This is the tubing bender I have.

This is a better picture of the business end of it.

 

It will bend 3/16, 1/4, 5/16, and 3/8 tubing. The grooves in the half round shoe are almost as deep as the total diameter of the tube, and this holds the sides of the bend from moving out, and this makes it harder for the tube to kink.

 

When you try to bend a tube, several things happen. The inside of the bend has to shrink, and the outside of the tube has to stretch. The closer the inside of the bend in the tube is to the outside of the bend, the less stretching, and shrinking has to happen. This makes the tube want to collapse. In order for the tube to collapse, it had to get bigger perpendicular to the bend, and this allows the sides parallel to the bend get closer. The round tube becomes oval. Holding the sides of the tube makes it harder for the round to become oval, and less likely the tube will kink

[Tristin]

You could always fasten some sort of screen on the end and use compressed air to blow whatever media your using into such a long pipe.

[hang_510]

perhaps using a generic tubing bender

a good tool will save a lot of hassle.

[jeffball610]

Like I keep telling my students, "just jump in with both feet and do something". I did something and it seems to work. The idea of filling the fuel line with baking soda or any medium for the length of tube I'm using just doesn't work. The idea of using sand or filling seems to revolve around the concept of making the tubing radius as small as possible. By simply increasing the radius of the bend, you can eliminate the kinking of the tubing.

I took the approach of making several smaller angle bends to get my desired bend. It's not perfect, but it seems to work pretty well. I also took out a lot of the bends I put in the brake line (that would have made them run identical to each other), as those bends were much too sharp for 3/8" tubing.

I have the fuel feed line 95% complete, only needing to cut a hole in the floor to point the line at the fuel tank (my lines run on the driver's side while the stock lines ran along the passenger side). After I'm sure this line looks and works correctly, I will bend a nearly identical line for the return fuel and start flaring the line for connections. I'll post some pics of what I've got and hopefully this will help others.

[jeffball610]

Still don't have any pics for you guys. I had to order some more parts to complete the fuel system. However, I now have another issue. How to connect -6 fuel line to the stock fuel sender. I'm using a Z31 fuel pump unit, and the lines seem to be about 8mm (close to 5/16) There isn't enough room to cut and flare the ends of the lines to adapt it to AN fittings. Anyone have experience with this that can lend some info?

[jeffball610]

Well, maybe I'll throw you a bone and show you my fancy tube "un-bender".

So this is a Harbor Freight engine stand with two idle pulleys and a water pump pulley from a 4G63. I simply bolted each up to the engine plate and put them in place to the bend (or un-bend) that I wanted. I had to use some vice grips to hold the arms a little better, as they tended to slip a little when I put too much pressure on the pulleys.

Top view. You can see that the water pump pulley is just the right size for 3/8" hard lines.

And a closer look at the idle pulley. Not pictured is the pulley behind the water pump pulley. It is the tensioner pulley for the balancer belt. It was the perfect size to fit into the water pump pulley and then I welded it through the bolt holes on the front.

 

I used these parts because they were laying around. The actually worked pretty good. I think they work better to bend lines, but they did a decent job of helping to straighten out the coil of fuel line to that I could work with it. Now if someone could answer my previous post, I might have a running car soon.

[TENDRIL]

nice man thats awesome

[jeffball610]

A member on MotoIQ sent me a link to an Earl's video. This is exactly what I need to finish my hardlines. Wish I had known sooner, and I may have done this for all of the hard lines.

[gpimm]

A member on MotoIQ sent me a link to an Earl's video. This is exactly what I need to finish my hardlines. Wish I had known sooner, and I may have done this for all of the hard lines.

 

OK, don't hold out on us...

 

Post the link!!

[jeffball610]

Whoops :D Here you go:

http://www.anplumbing.com/page/16

 

Ordered two today. Unfortunately only Earl's offers the 5/16" adaptors and they come in the ugly blue/red. I really wanted some more black anodized fittings to match the rest of the car. Oh well. Maybe just throw some paint on them since they'll be hiding in the trunk.