Replacement "S" shaped fuel hoses







I couldn't see buying them again for the going price and then again in another 5 years, so I came up with a solution. The bends are sharp enough that the hose will kink or collapse, so I bought these Uni-Coils and some high quality fuel injection hose in 3/8 and 1/4" and made my own.

 

Intriguing. Let us know how they are holding up 5 years from now.

Seriously, though, looks like a great idea. I did basically the same thing with the hoses to the heater core. Hmmmm.......haven't even looked at them in a couple years at least. Think I'll crawl under and check 'em out tomorrow. Thanks for reminding me, bud!

Scott

 

You run un-coated headers by chance?
Those hoses look to be cooked from too much heat.
It could be they are poor quality as well.
Maybe ethanol damage?

 

The most damage is on the outside of the hoses, so not likely ethanol issue. The headers are uncoated, but the damage is clear down by the fuel pump also, I have no other heat issues. The hoses are still flexible, doesn't seem like they are cooked. Crappy parts are getting to be the norm.

 

Cr@ppy parts have been the norm since China started making those low-dollar parts. They're good at making them low"er" dollar than anyone else. How? Make them out of cr@p materials.

They LOOK the same when new......

Best advise: Always ask if there are alternative parts to choose from. If so, NEVER buy the cheapest one.

P.S. The 'spring support' idea is a really good one. You can buy good quality 'straight' hose and bend it without kinking!!

 

It seems from my experience china rubber products are often very poor. There has to be something they are doing to save money which causes the rubber to dry up and crumble in short order.. the mini starter I bought 2 years ago had the insulation from the wire to the soleniod to motor completely crumble and fall off and it wasnt even installed yet.

 

I reviewed your original hose pictures with a former engineer that used to work for me at Saginaw Steering Gear. His opinion (and mine) is that we have ozone cracking of the fuel hose cover material. If the hose material was brittle and cracking (and showed progressive worsening cracking as the hose neared an exhaust pipe heat source) then I would say the hose was just routed too near a heat source. But from your description, this is (was) not the case.

When we developed rubber parts for hoses, lip seals, gaskets, flexible couplings, etc, we always specified a certain level of ozone resistance to be compounded into the rubber materials by our suppliers.

Ozone is freely available in the atmosphere. It also can be generated through "sparking" of an alternator. Although the Vette alternator is on the other side of the engine compartment and would not be considered a failure source on well specified materials.

Our materials lab had an ozone cabinet just to test such parts during developement and on a continuing quality control standpoint.

Last of all, we are really screwed as poorly or cheaply compounded materials are phoisted on the unsuspecting public. Try to purchase known, domestically manufactured rubber parts that hopefully have had the influence from OEM manufacturers with regard to good compounding.

Amen!

Jim

 

can any one recomend a quality supplier as I think I should change mine.

 

That would be my take....

 

Hoses have inner liners that are compounded to operate properly when exposed with the fluid that it is designed for. For instance, liner material might have been compounded to work with gasoline and lead additives but never comprehended ethanol blends.

Then some type of nylon, rayon, Kevlar, steel, or other type of braiding sorrounds the liner material and provides pressure capability.

Lastly a cover material is selected to work correctly in the operating external environment. The cover material does not necessarily have to be the same as the liner material and in most cases is not the same as the liner material.

When I look at the hose pictures, I note that the hose end (where the screw clamp attaches the hose to the fuel pump or fuel pipe) seems to be unaffected. Could it be that the hose clamp protected the cover material from direct ozone attack?

Also, ozone will first attack the more highly stressed areas of the rubber material. Note that the cracks seem to located on the outside of the hose bend where the cover would be under tension and stressed the most. The hose cover is not cracked on the inside of the bend where it would be under compression. Also the hose does not appear to be cracked on the very end (after it leaves the screw clamp).

Jim

 

Thanks Jim, for the detailed failure analysis. That's very interesting, would you like to see a picture of the hose sliced open for an inspection of the inner liner? OK, here's the pics, the liner looks fine, doesn't seem to have failed from within.

 

Wow! I can't believe how nice the inside looks, but how horrible the outside looks.

Scott

 

 

Now that Jim mentioned it I see that the hose is only damaged beyond the hose clamp until the next hose clamp.
Interesting.
Is it possible that the inner liner of the hose was damaged when tightening the hose clamp and that allowed fuel to seep in between the two layers and since the outer liner is of a different composition than the inner liner it was not able to tolerate the constant exposure to fuel and began to crack?

Interesting theory on the O3 exposure.
Question though. If it was ozone, then what was it's source? Plug arcing?
And wouldn't there be ample airflow from just the cooling fan to dissipate the ozone if it was present from a source such as the plug wires arcing?
How about a header leak? But again, lots of airflow from the cooling fan seems unlikely that exhaust gasses could collect sufficiently to cause damage.

 

I replaced mine about 10 years ago with replacement hoses from Dr. Rebuild. They were more expensive than some of the other suppliers, but I felt the price was worth it for such an important part. Have not inspected them in awhile, but I can say there are no leaks. Will make a visual inspection today.

 

I work with machines that create quite a bit of ozone as a byproduct of very large voltages through corona wires and pin arrays (they even require ozone filters to be installed) in them and I haven't seen that kind of damage to the rubber components (I do see a lot of oxidation of the plastic distributor cap material (bakelite?) and even carbon tracking which sometimes shorts things out.

Ironically I have a lot of equipment at a well known power dam and I was just there again about a week ago wondering why the rubber components in their machines seem to keep drying up and crumbling so quickly..... I think now its very possible that there is a higher level of ozone from the power generating turbines in the building.

 

The hose wasn't actually leaking yet, but given the look of the outside of it, I thought it was an accident waiting to happen.

 

For the most part, the person (i.e. company) manufacturing the fuel hose would compound the inner liner to be completely compatible with the fluid being transmitted and the working temperatures of the fluid. Then the cover material would be compounded to be compatible (to an extent) with the fluid but more directly designed to work in an engine compartment environment and temperatures.

Overall, I would say that a U.S. manufactured fuel hose would most likely meet most OEM specifications. The hose may also say something like meets SAE (Society of Automotive Engineers) fuel hose specifications. I don't have current reference materials available any longer (I retired 13 years ago) so I can't quote the actual SAE spec numbers.

One more comment: The OEM style hose was manufactured and cured on an "S" shaped mandrel. This allowed the formed hose to arch through very tight bends without kinking. Placing external wiring (Unicoil) around a straight piece of rubber is a good way to prevent kinking. However, it will not do any good on a poorly (incorrectly) compounded hose.
Jim

 

I did something completely different than those here. I cut and bent steel tubing with a very tight radius, without flattening the tubing. I used those pieces for the bends in the original "S" hoses, and then used rubber fuel line for the straight pieces and to attach the steel to the fuel pump nipples. This allows for any flexing that might occur. I did this change over 15 years ago, and it's still in place with no leaks. The steel tube bends were a bugger, if I remember correctly. I made quite a few of them before I got the ones I was pleased with to use.
I'd love to get some pics for you guys, but that can't happen until sometime in April, as the Vette is put away for the winter. And right now it's a little on the chilly side here in Western New York. Happy Holidays.
Duane

 

That is something. Never thought they would break down like that. I have old USA made fuel hose 15 years old or more looking better on my old truck.