A Substitute for Submersible Fuel Hose

[TopNotch]

I had to change the fuel pump in my white Fiero (again, sigh), and I couldn't find any submersible fuel hose anywhere. I tried 3 Napa stores, including the big one on Peachtree Industrial. No luck. So I decided to find a substitute.
I went to Ace Hardware where they sell various bulk hoses by the foot. And I saw some polyethylene high pressure air hose of the right diameter. Since plastic gas cans are made of polyethylene, and gas doesn't harm them, I figures that the polyethylene hose should work, so I bought a foot. As a test, I cut off a small piece and put it in a small container of gasoline. It's still soaking there, and so far, no damage at all.
So I cut off a piece and used it to connect the pump to the metal line. And this time, I fixed the gas gauge sender, by removing the connectors and soldering the wires to the appropriate tabs. One of the connectors wasn't making contact.
Now I'm in the process of putting the tank back in the car. We'll see what happens.

[TopNotch]

The car's back together, runs fine, and starts more readily. I think the low pressure was hindering starting.
ps. The gas gauge works, too.

[Raydar]

Good info. Thanks for sharing.

[Fierofool]

When he said polyethylene, my mind pictured the black polyethylene of the type used for long life underground water lines.  Today he showed me a piece of it.  It's very flexible, multi-layer, and imbedded fabric reinforced.   

[TopNotch]

Well, so much for that idea. My car was hard to start this morning, so I checked the fuel pressure. It was Ok with the engine running, but it bled down almost instantly when I shut it off.
Fortunately, I found some submersible hose on Ebay. For those of you who want to try other sources, Dayco and Gates make it. The part number for one foot of Dayco is 80161.

[Fierofool]

NAPA on Peachtree Industrial in Norcross has Ethanol Submersible hose.  I found 5/16 ID in one foot lengths.  It's Part Number NBH H209 at a price of $33.  3/8 ID is Part Number NBH H213 at $40 for one foot.

Submersible Fuel Line Hose is capable of handling multiple types of gasoline and fuels, including gasoline, alcohol-extended gasoline, ethanols, biodiesel or diesel fuel in fully-immersed, mobile and stationary applications. Most fuel lines are only designed to handle fuel on the interior of the hose, which can be damaged if the exterior is exposed to fuel. Engineered for fully submersible use, these hoses are excellent for use on gas tank fuel pumps.


Comprised of an FKM tube and cover with synthetic fiber reinforcement
Exceeds required SAE 30R10 standard
Temperature Range: -40 Deg. F to +302 Deg. F (-40 Deg. C to +150 Deg. C)

[TopNotch]

The steel line that has to connect to the fuel pump is 3/8", so I need 3/8" ID hose. I asked the Peachtree Industrial store if they had some, and they didn't. There's no way I could force 5/16" hose on that line.

[Fierofool]

Thought it was 5/16.  I'll look again.

3/8" ID is Part Number NBH H213 and in stock.  Order now and pick up tomorrow.  $40.99 for one foot.

[PK]

Well it was worth a try I guess.  I rebuild unobtainable motorbike fuel pump diaphragms with overhead projector acetate...has worked for years and material is free!!!  Took some testing to be sure it wouldn't spectacularly fail.

I too had read 5/16" somewhere and had this stuff in my watch list https://www.ebay.co.uk/itm/382558398973

So good to know I may have the wrong diameter!

Phew they do 3/8" too

Click here

[Fierofool]

I was curious about the size, so I pulled out two sending units and my dial calipers.  The steel line is about 5/16 diameter, except that it's sized down at the point where the hose fits onto it.  That diameter is 0.315 inch.  The discharge end where the steel line transitions to the engine bay fuel line is still 5/16 inch.  That might be where the confusion originates. 

[TopNotch]

On my car, the supply line (measured with a caliper) is always 3/8", from the pump to the little hose that connects the tank to the fuel filter line, and that's 3/8" also. The return line is 5/16".
in any case, I got some 3/8" submersible hose today, and everything is good now.
I wasn't entirely wrong about the polyethylene hose, it still showed no damage from the fuel, but because it is plastic, not rubber, it "changed shape" because of the hose clamps around it, with the result that it wasn't clamped tight anymore, resulting in leaks.
And here's a tip (which will probably get lost in all this text). To make slipping rubber hoses onto steel lines easy, moisten a Q-tip with dish washing liquid and use it to swab the inside of the hose where it will be slid onto the steel line. It will go on much more easily. I've done this a number of times with no harmful effects of any kind -- it just makes the job easier.