Omix Flex Fuel Hose

[Hawkshadow]

Be warned about the flex fuel hose that comes in the pre-formed fuel line kit from Omix. The rubber on mine started cracking on the outside almost immediately after it was installed. Before I could get a new one made in the spring, the combination of cold temperature in the garage and cheap brass in the fitting lead to the fitting cracking and leaking fuel. That fuel has now leaked onto the horn wire and completely destroyed the insulation…



I'm planning on having a new hose made up at the local shop (Princess Auto for those in Canada) that custom makes hydraulic lines if they have a fuel safe hose. If anyone sees any improvements to suggest before I make up and install the new hose please let me know.

[billybob]

You can go to any good welder supply outlet and buy the fittings and ferrules. They should also have an inexpensive tool to crimp the ferrule to the hose. It works in a vice or small press. Very simple to use. I've used it on a lot of air hoses and never had a failure. I'll try to get a picture tomorrow.

[oilleaker1]

You are on the suction no pressure side. You can buy barbed hose fittings and hose at NAPA and fix it cheap.

[wesk]

I usually agree with John but this time I have to add my 2 cents.

Crimp it your self kits are generally cheap and not reliable. And since most folks taking this route do not have pressure testing equipment you cannot certify that the hose will with stand the specific pressure that crimp was designed to hold. Yes it is the suction side (low pressure) but the 400 to 600 pound test is not to burst test the hose. It is only done to ensure your crimp is correctly done. If your crimp is poorly done or incorrect vibration and motion will soon loosed it. Also this test insures your joint will not suck outside air in which can give you a lot of grief troubleshooting low fuel delivery rates.

Barbed plain hose fittings, cheap across the counter one or 2 ply fuel hose is a cheap way but again it is subject to more rapid deterioration and motion can easily loosen the hose.

All of the above time spent could easily have been better put to use maintaining the rest of the jeep while you proceed with your original plane which was the best idea:

I'm planning on having a new hose made up at the local shop (Princess Auto for those in Canada) that custom makes hydraulic lines if they have a fuel safe hose.

I often fabricate quality hose assemblies for aircraft and when I want a better/safer design for my auto applications I often go with AN fittings and Aeroquip/Stratoflex hose just like the fuel dragster use.






These are the only tools beside a cutoff wheel and vise that you need.

The teflon lined hose with external steel braid and internal steel braid is the top of the line and runs about $10 a foot. The more common hose I use for fuel and hydraulic use in petroleum products is 303 hose medium press (3000 PSI) ($8 / ft) however in this application 306 is fine medium press (300 PSI) ($4 / ft). .


Aeroquip spec sheets for low and medium pressure hose assemblies:
http://www.eaton.com/ecm/groups/public/ ... 5962~5.pdf

[GPA]

Lucky the fault in the hose was revealed early. Could have burned the passengers and the jeep. Manufacturers like this Omix company, looks more like an industrial waste producer. They have caused so much grief, headache and financial damage to their customers. If they do it on purpose and sabotaging jeeps, than they are doing a good job. If not, they should be the first to realize that parts manufacturing is just not for them, should sell off their equipment and disappear. Would be better for everybody.

[4x4M38]

Hawk,
Unless you have standing water in your fitting I doubt the cold weather had anything to do with cracking the fitting. My guess is that it is machined very thinly across the flats, and you during installation or someone in manufacturing may have started the crack. Flexing finally made the crack appear and exacerbated the situation.

Like the sector shaft issue that we went through a while back which Omix Ada addressed, I'm thinking it is up to us as a community (sadly) to document the problem. If it is a production issue it has happened before and maybe just missed or repaired and passed on. And it will happen again.

It is a safety issue and needs to be addressed.

Can someone with an OEM or reliable part measure the fitting externally for length and as well as width across the fitting flats to determine maximum width?

And can someone measure the same dimensions on an out of the package Omix Ada part? This might tell us if the fitting shell is too thin. I am assuming the steel line double flare fitting is on spec. (Might be too much to assume).

Has anyone else installed any of these kits or maybe just the flexible fuel line itself from Omix Ada?

Does this path forward make sense?

[Hawkshadow]

Thanks for the replies gents. Does the routing look similar to what everyone else has in their M38s, without too much of a bend for the hose?

Wes, when I have a new one made up, should I ask them to use one of those fittings that comes off at what looks like a 45deg angle to reduce how much the hose is bending?

Here are some additional pictures after I removed the hose today. I am astonished that a hose in service for less than a year would be this cracked on the outside and have failed in this way...

[Hawkshadow]

Having a new hose made is turning out to be more difficult than expected. I spent 4 hours running around to different shops with no success. Auto shops, hydraulic shops, hose and fitting shops, high performance vehicle shops, marine shops - nothing. None have the fittings, and had no idea how to order them in… I didn't expect it to be this difficult, am I missing something?

[wesk]

If you are asking the shops to duplicate that Omix-Ada hose that may be the problem. They may not have those specific fittings available.

Bring them your 90 deg nipple off your fuel pump and the tube that runs from the hose to the shutoff valve. Tell them to make you a hose that length that will fit your nipple and the inverted flare nut on your tube.

This is the spec for the proper hose:

33H127-60
Nonmetallic Hose; Rubber synthetic tube

33H12760

Specifications
For Use With/On: Grumman a10 aircraft AGAV
Burst Test Pressure: 1250.0 pounds per square inch single response CQBD
Cross-sectional Shape Style: Round AAGR
Hydrostatic Test Pressure: 400.0 pounds per square inch single response CRDW
Material: Rubber synthetic tube MATT
Maximum Operating Pressure: 200.0 pounds per square inch single response CQGM
Media For Which Designed: Fuel/oil, hydrocarbon single response MEDA
Minimum Inside Bending Radius: 4.000 inches ACKH
Nondefinitive Spec/std Data: 4 size ZZZT
Outer Covering Environmental Protection: Abrasion resistant and hydraulic solution resistant and oil resistant CRJM
Outside Diameter: 0.469 inches nominal ABKV
Inside Diameter: 0.250 inches nominal AARX
Inside Surface Condition: Smooth CRWL
Layer Composition And Location: 1st layer braided cotton cord err-100 CQCS
Layer Composition And Location: Outer layer molded rubber, synthetic err-100 CQCS
Specification/standard Data: 81349-mil-h-5593 government specification ZZZK
Temp Rating: -65.0 deg fahrenheit single response and 160.0 deg fahrenheit single response ABJH
Vacuum In Torr: 254.0 CRSM
Federal Supply Class (FSC): Hose And Flexible Tubing
National Stock Number (NSN): 4720-00-540-1962
_____________________________________________________________

The adapters are Aeroquip:

Male inverted flare is PN 4740-4 or AEQ4740-4

Female inverted flare PN 4743-4 or AEQ4743-4

Here's a link to a catalog page that will help
https://www.greggdistributors.ca/pdfs/CatV001.pdf

[Hawkshadow]

When I compared quotes that I was receiving to purchasing a complete new hose, I gave up on having a new one made and ordered a new hose from BCA. His products have always been excellent and this hose was no different. The differences in quality were immediate compared to the omix example. Much thicker brass, proper sized fittings, and better quality hose.