DOT vrs Standard Nylon hose

[rustystud]

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[Keith_J]

Nylon is a polyamide, the different layers are for UV and moisture resistance. Nylon is quite sensitive to both. The non-DOT tube you are showing is polyethylene which has very low temperature resistance but is quite good on moisture.

 

[Floridianson]

Yea believe your right Home depot does not sell polyurethane fuel line. Thought the problem was finding the right size nylon line for the injector return lines. That or use DOT nylon lines.
Thought tom said he use hard wear store fittings stuff with no problem.The DOT fitting are thicker I believe because the DOT requires that the line and fittings must with stand 350 pounds of pull and not come apart or fitting threads pull away from attachment point. Yes I find it easer to get DOT stuff at NAPA.
https://www.steelsoldiers.com/showt...highlight=Nylon+line+for+injector+return+line

 

[Scar59]

The big truck parts houses (Truck Pro, Truck Inc, etc) sell DOT compliant hose by the foot. Plus they have all the fittings to address the job. I have found some great assistance from the local truck parts houses. Take your MV for a drive to the truck parts shop. The parts counter guys love them and become your new friend. They'll even give you the fleet discount.

 

[Floridianson]

As you can see the return line realy sees no flowing fuel. No plugs on the return fittings and no fuel dripping on the injector. Yea my NAPA is on the same street as my trucks so yea it is easer. Biggest problem with brass is over tightening it..https://www.youtube.com/watch?v=uUFJ2s6XPlw

 

[rustystud]

Nylon is a polyamide, the different layers are for UV and moisture resistance. Nylon is quite sensitive to both. The non-DOT tube you are showing is polyethylene which has very low temperature resistance but is quite good on moisture.

I'm aware Nylon is a polyamide. The different layers are not just for UV and moisture resistance. They are there for extra strength: ie "fiber reinforced" . That is why they can withstand 200PSI pressures. That regular poly hose from Home Depot will not withstand 200 PSI.
This posts intention was to bring awareness to people who might not know, that there is a major difference between DOT hose and fittings and NON Dot hose and fittings.
Safety being the major concern here.

 

[m16ty]

I had a return line blow out in the Lowes parking lot one time. I did get some of their cheap tubing to fix it until I got home. You are correct, the big box store tubing is a different dimension than the DOT tubing, but will work in a pinch, if you also use the matching ferrules.

Anyway, the cheap tubing did work for me to get home, and I didn't replace it because it wasn't leaking. I did notice, after about a month, that the tubing I replaced had turned really soft and was about to blow again. Evidently, the fuel had broken down the cheap tubing in short order. I pulled the truck in the shop and replaced all the return lines with DOT tubing, haven't had a problem since.

 

[Floridianson]

Do believe it's not cheap it's like Keith_J said they have water line and will not hold up to chemicals. Used more for you ice maker. 12 years ago when I got my first Deuce I looked in to a company that had nylon 6/6 line that would hold up to chemicals/petrolum products. Probably close to what came on the truck. Used standard compression fittings and working pressure of 500psi and burst pressure of 1500. Problem was they only sold 100 foot of it. Was so much easer than wait for shipping and also get 90 extra feet just go my NAPA and get the DOT stuff. Yes we always want to be safe when dealing with fuel or air on our trucks.

 

[gringeltaube]

............ In picture three you see a standard polyurethane hose. ............ DOT hoses can withstand pressures over 200 PSI and handle air, water, fuel, and oils. Standard polyurethane hoses cannot.
.............

This thread is about the many different types of NYLON tubing - and when to use what, right? And the one shown in pic 3 seems to be standard industrial Nylon (polyamide) hose? Not sure why you are bringing in polyurethane, which is a completely different material, for different uses? Maybe you meant to say polyamide, instead of polyurethane? But then, even standard Nylon (polyamide) tubing easily resists 200psi at room temperature - just not with a (certified) 5:1 safety factor. And it can very well be used for all kind of fuels and oils as well as brake fluids, including DOT5.

All DOT hoses have fiber reinforced "polyamide core" with a Nylon cover/sheath........

Not exactly... There is a "Type A" (= non-reinforced, single-wall extruded Nylon) and a "Type B" which has a pure Nylon core with a fiber reinforced Nylon jacket/sheath. Type A is allowed for outside diameters up to 5/16" while type B must be used for sizes above 5/16". Typically for air brake applications, both types have to meet SAE J844 and DOT FMVSS49CFR 571.106 specifications.

 

[rustystud]

This thread is about the many different types of NYLON tubing - and when to use what, right? And the one shown in pic 3 seems to be standard industrial Nylon (polyamide) hose? Not sure why you are bringing in polyurethane, which is a completely different material, for different uses? Maybe you meant to say polyamide, instead of polyurethane? But then, even standard Nylon (polyamide) tubing easily resists 200psi at room temperature - just not with a (certified) 5:1 safety factor. And it can very well be used for all kind of fuels and oils as well as brake fluids, including DOT5.

 

[77 AMG]

Thanks to all the useful contributors in this thread. I am getting ready to start replacing all of the brake and fuel lines on my Deuce, so, this discussion is quite helpful, even if it has a moment of "disagreement'.