Volume III, Issue 6, Page 19


Braided stainless looks good, but there’s weirdness inside

aise your hand if you thought stainless steel braided hose was the highest quality you could buy. Huh? I know I did. I considered the bucks I shelled out as an investment in quality--something I wouldn’t have to think about again. 

Well, not so fast, bud.

I lost a quarter of a tank of gas in five minutes when my main fuel hose failed last week.  With gasoline at French wine prices, I watched $150 or so of fuel puddle on the ground. 

I put the car up, pulled the hose off and cut it apart to find the failure. That turned out to be so not easy. My hose had literally hundreds off cracks, any one of which could be the designator. The hose looked 30 years old from the inside, and felt like it was made of wood. Cutting through the hose to see the inside was like whittling on a Cub Scout Pine Wood Derby car. 

I pulled all the hose off the car and inspected carefully. The fuel return line, coolant lines, and breather lines all looked okay, but every single hose in the main fuel line path was bad—deep, no huge cracks, crackly to the touch, and with little flexibility. Right then, it seemed to me that the hose isn’t compatible with pump gas. 

I contacted the manufacturer (you’ve heard of them), and asked if the hose was compatible with pump gas.  The response was that in normal use the hose is good for 4 to 6 years, but that in cases where the hose sits dry after being exposed to gasoline its service life will be half that.  Think about that: how many of us drive our hot rods enough to keep the fuel lines continually filled with gas?  I’d guess very few.  And the manufacturer knows it, but there isn’t a whiff of information about the hose characteristics (including life expectancy at circumstances). No asterisk, no nothing. 

I think there are thousands of cars out there with owners happily thinking that since they spent a lot of money on their fuel line hose, it will last the life of the car.  I’m here to tell you: it won’t.  And the manufacturer isn’t telling, either. 

I just finished swapping all the fuel lines to aluminum hard line, and am using a short piece of nylon-covered braided hose (from another manufacturer) for the necessary flex connection between the engine and chassis.  I should have (and meant to have) done it that way to begin with, but I got lazy at the end of my build, and used about 30 inches of hose to make the final connections and in my fuel rail.

After doing some more research, it seems that the safest fuel line you can use is Teflon-lined (like for power steering) or something called PTFE (the ‘T’ stands for Teflon).  Both of those hose technologies are rated for fuel and resist permeation (where you can smell gasoline through the hose).  In fact, the safest route may be to use ordinary parts store rubber fuel line (just make sure it has a J30R9 designation for fuel injection, and J30R7 for carbureted motors) and a high-quality worm-drive clamp.  Once funds free up, I’m going to swap over to PTFE rated hose with crimped ends from a high-end race shop.  That hose will cost me $200, but it will accommodate pump gas indefinitely.

Luckily for me, I just lost some fuel, and some money.  I have nightmares of far nastier scenarios. Fuel leaking on red-metal hot headers.  Now I’m looking for a fire extinguisher.



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