Upgrading/replacing fuel line

[TechnoWeenie]

From what I'm seeing in the TM, it appears that the fuel line is 3/8.... Which is equivalent to about a AN-8 line. AN-6 would be 5/16 and AN-8 would be 7/16...

Would there be any issue going to an AN-10 line, which is 1/2"? It would seem the increase in diameter would be relatively negligible. The ports on my planned spin on replacement fuel filter housings are 7/8 UNF which is super simple to toss an AN-10 line onto......

The pump is metered, correct? So, I don't have to worry about the volume of the line and its size as a variable in the fuel delivery system? Doesn't the unused fuel return to tank anyway?

I want to settle on a standard, and redo all the fuel lines in that standard.

Plain rubber lines don't seem that great.

AN-10 lines that I'm looking at are PTFE.....with stainless mesh outer covering..

I'm hoping to add in an in-line fuel cutoff, and inline pre-filter...


Am I overthinking it with the AN-10? Should I just replace the hard line and the short rubber sections?

Anyone know off hand the total length of the fuel system, in feet?

 

[ToddJK]

This is not a bad question. There are differences in one kind of line to the next but it's based on what it is. 3/8" plastic fuel line may not be the same as 3/8" air brake line as I found out. The plastic fuel line was larger in the sense the fittings were too sloppy and the crush nuts wouldn't fit over the line and neither would the ferrules of 3/8". The plastic fuel line was ordered off Amazon and while it said it was 3/8", I think it was metric since none of the 3/8" fitting would fit. Using 3/8" air brake line or tubing from NAPA, which has the Teflon coating inside, all the fittings fit as they were supposed too.
Stick with air brake line or air brake tubing, there should be no deviation from the standard 3/8" ID that is used on the deuce and the same also applies for the 1/4" and 1/8" (flame heater).

I don't think changing the diameter to a larger size would affect the IP, perhaps one of those who did a file line conversion can chime in, but a lot of it came down to how much money one wanted to spend as well as their patience. If did convert over to some type of AN line, if different sizes are used, I think making note or a record of some kind of what sizes specifically are used from what to where would be a great future reference, whether it's for you or perhaps a future owner should the truck ever trade hands.

 

[TechnoWeenie]

This is not a bad question. There are differences in one kind of line to the next but it's based on what it is. 3/8" plastic fuel line may not be the same as 3/8" air brake line as I found out. The plastic fuel line was larger in the sense the fittings were too sloppy and the crush nuts wouldn't fit over the line and neither would the ferrules of 3/8". The plastic fuel line was ordered off Amazon and while it said it was 3/8", I think it was metric since none of the 3/8" fitting would fit. Using 3/8" air brake line or tubing from NAPA, which has the Teflon coating inside, all the fittings fit as they were supposed too.
Stick with air brake line or air brake tubing, there should be no deviation from the standard 3/8" ID that is used on the deuce and the same also applies for the 1/4" and 1/8" (flame heater).

I don't think changing the diameter to a larger size would affect the IP, perhaps one of those who did a file line conversion can chime in, but a lot of it came down to how much money one wanted to spend as well as their patience. If did convert over to some type of AN line, if different sizes are used, I think making note or a record of some kind of what sizes specifically are used from what to where would be a great future reference, whether it's for you or perhaps a future owner should the truck ever trade hands.

The absolute lowest pressure rating on the lowest quality stuff is 300PSI, with most being ~1k PSI.. So even going cheap (which I wouldn't), nothing would prevent me from replacing both the air and fuel lines with AN-10... A 1/2" air line would be a big upgrade, heh. It would also allow me to put in check valves...

I'm a big fan of fixing things before they become an issue, and being that the rubber and copper on this truck are 50+ years old, it's better to do it now instead of on the side of the road.

I already have new brake cylinders, brake flex lines, and I'm debating replacing the cupronickel brake lines...

The idea isn't just to put in new stuff, it's to simplify on-road repairs... No need to carry 4 sizes of line and 18 fittings.... Just one size line and maybe 3-4 fittings/couplers to replace a failed/damaged line since they'd all be the same size.

 

[Gypsyman]

I was going to type all of this out but a chart is quicker. AN sizes for future reference.

 

[ToddJK]

The absolute lowest pressure rating on the lowest quality stuff is 300PSI, with most being ~1k PSI.. So even going cheap (which I wouldn't), nothing would prevent me from replacing both the air and fuel lines with AN-10... A 1/2" air line would be a big upgrade, heh. It would also allow me to put in check valves...

I'm a big fan of fixing things before they become an issue, and being that the rubber and copper on this truck are 50+ years old, it's better to do it now instead of on the side of the road.

I already have new brake cylinders, brake flex lines, and I'm debating replacing the cupronickel brake lines...

The idea isn't just to put in new stuff, it's to simplify on-road repairs... No need to carry 4 sizes of line and 18 fittings.... Just one size line and maybe 3-4 fittings/couplers to replace a failed/damaged line since they'd all be the same size.

I understand where you're coming from. There has been confusion and issues among different types of fuel/air lines, so going with AN type of line is not a bad idea and it is better and/or easier to make repairs with fewer parts if need be. I would be interested to see a parts list and pictures of the change over when you finish it. I've had a fire once due to a line melting on the air intake, so any chance in future endeavors to reduce the risk of fires is a vast improvement.