fuel hose materials

[shogun]

In case you have problems with your fuel hoses that after 1 year or so they get brittle and start to leak again, you most probably bought the wrong material of fuel hoses. BMW uses for the engine bay and hot spots FKM material, the usual aftermarket fuel hoses are cheaper and are made of NBR. The main difference is
NBR hose up to 100C, FKM to 200C!
http://www.bimmerboard.com/forums/posts/1269443
http://www.bimmerboard.com/forums/posts/1269444

FKM grades in the link below from Trelleborg, Denmark, which is one of the major players in seals, hoses etc
Fluorocarbon Rubber (FKM)
In automotive applications , FKM is known in particular for its very good resistance to fuel, oil and aggressive media as well as the excellent resistance to ozone, weathering and ageing. Depending on structure, fluorine content and used curing system FKM materials can differ with regards to their chemical resistance and cold-flexibility. The operating temperature of FKM ranges from -20°C/-4°F to 200°C/392°F, for a short period of time up to 230°C/446°F.

Special FKM grades can be used down to -45°C/-49°F ( XLT grades of Trelleborg Sealing Solutions ).The material has:
•Resistance to oil & grease
•(problematic additives!)
•Very good resistance to fuels
•Excellent heat resistance
•Excellent weather & ozone resistance
•Good acid resistance

Applications:
Due to high chemical resistance and low swelling in fuels (especially when containing ethanol and methanol) FKM can typically be found in the complete fuel supply chain (fuel injectors, quick connectors, high pressure pumps, etc.). Additionally, gaskets in ECUs for gear boxes are also a field of application.

https://www.tss.trelleborg.com/globa...sion-342452606


NBR acrylonitrile-butadiene rubber
NBR has good mechanical properties, low compression set, good low temperature behavior (mix-dependent to -50 ° C) and higher abrasion resistance than most other elastomers. NBR is highly resistant to hydraulic oils, mineral oils, petroleum products and oil in water emulsions, water glycols and animal and vegetable oils, gasoline, flame retardant oil in water emulsion (HFA liquid), water in oil emulsion (HFB liquid) and solution of Polymers in water (HFC liquid). Ozone and weathering resistance is considered poor. Temperature range: -50 to + 100 ° C. Applications: Standard material for oil- and fuel-resistant seals, scrapers and moldings for general applications without exposure to ozone or weathering. The most diverse compounds can also be processed with approvals (eg KTW, DVGW, etc.) or with fabric reinforcements.

[TxGR8White]

Only BMW Fuel Lines for my BMW's - It just does not pay to cheap out on this (plus they really aren't that expensive - especially when you have to replace the non-BMW stuff constantly).

[JDP530]

I used the Gates Barricade multi-layer fuel hose that is compatible with most fuels including 100% methanol: http://ww2.gates.com/europe/brochure...ation_id=19079

Looks like Gates Submersible fuel hose is a FKM hose using a fluorocarbon outer casing: https://ww2.gates.com/europe/brochur...cation_id=5165

[NashTom]

I just finished restoring my fuel tank and had to research fuel lines. My generic conclusion is SAE J30R9 for non-submersion applications and SAE J30R10 for submersion - no manufacturer loyalty. With a special definition for the Gates hose. Specs as follows:

Copied from SAE J30R9 Specification-
Fuel Injection Hose Medium-Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R9)
Hose primarily intended to meet the demands of fuel injection systems. These would include, for example, electronic fuel metering (EFM), electronic fuel injection (EFI), throttle body injection (TBI), and the like. Other areas of utility are those applications requiring fuel permeation resistance exceeding 30R8 and ones which require fuel resistance greater than that obtainable with 30R6, 7, and 8. Exposure of this hose to gasoline or diesel fuel that contains high levels, greater than 5% by volume, of oxygenates, i.e., ethanol, methanol, or MTBE may result in significantly higher permeation rates than realized with ASTM Fuel C. This hose may be supplied in either a coupled or uncoupled form, and is useful in the transportation of gasoline, ethanol extended gasoline, diesel fuel, lubrication oil, or the vapor present in either the fuel system or the crankcase of internal combustion engines in mobile, stationary, and marine applications. This hose has a maximum working pressure of 0.69 MPa (100 psi) up to and including 12.70 mm (1/2 in) ID. This hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in normal operating temperatures of 34 to 135 °C (29 to 275 °F) and intermittent use at 150°C (302 °F).

Copied from SAE J30R10 specification-
In-Tank, Low-Pressure, Uncoupled Fuel Hoses (SAE 30R10)
Hose intended primarily for use in fuel injection systems where the hose may be submerged in the fuel tank. The hose is capable of handling gasoline, alcohol-extended gasoline or diesel fuel used in mobile, stationary, and marine applications. This hose has a maximum working pressure of 0.69 MPa (100 psi) up to and including 12.7 mm ID. This hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in normal operating temperatures of 34 to 100 °C and intermittent use at 125 °C

The Gates non-submersed is interesting since they specify a significantly higher working pressure (225psi/1.5MPa) and slightly lower (257f/125c) working temperature and say they exceed J30R14. This is typically a specification for small engines. Gates has well exceeded the working pressures of that spec which is 50 psi. The T2 part of the Gates spec is for a working temperature of 125c which is above the base J30R14T1 spec (below).

Copied from SAE J30R14 specification-
Low Permeation, Low Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover Hose for Small Engines (SAE 30R14)
Hose which may be supplied either coupled or uncoupled for use with gasoline, diesel fuel, lubrication oil, or the vapor present in either the fuel system or in the crankcase of internal combustion engines in small engine applications.
Exposure of these hoses to gasoline or diesel fuel which contain high levels, greater than 5% by volume, of oxygenates, i.e., ethanol, methanol, or MTBE (methyl tertiary butyl ether), may result in significantly higher permeation rates than those listed for 30R14. This hose is for maximum working pressures of 0.34 MPa (50 psi) up to and including 9.53 mm (3/8 in) ID and for hose in excess of 25.40 mm (1 in), the working pressure is 0.11 MPa (16 psi). The hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in temperatures up to 100 °C (212 °F) for 30R14 T1, 125 °C (257 °F) for 30R14 T2.

My assumption is that since Gates uses a plastic inner liner on the non-submersion as opposed to FKM they have sacrificed a little on the upper temperature range 125c vs 135c in the R9 specification otherwise they would exceed the R9 specification. The plastic liner may also be the reason Gates calls out not meeting the kink resistance for 30R14T2. I do not know that this is correct - just my assumption.

I used Continental Elite that meets J30R9. Nothing wrong with the Gates since I do not think the fuel line is placed anywhere that would exceed 257f/125c and some may appreciate the higher working pressure. Funny thing was that I learned all of this when I was searching to purchase the Gates and could not easily find it when I needed it.

I am certain there are also testing differences to meet each spec but it would be a full time job to get to that detail. If I am wrong on any point please correct me. Hate if I were to spread bad info.

[biasvoltage]

This is great information. I, too, replaced the fuel hoses on my 750 with aftermarket 8mm hose sourced from CRP. After only a few months, the hoses underneath the brake master cylinder (which are subject to heat from the exhaust manifold) had deteriorated and were leaking. I replaced them with Gates Barricade 5/16" fuel line, and later replaced all of the rest of the hoses with the same. All of the CRP hose exhibited cracking on the exterior and some was actively weeping fuel. A year later and the Barricade hoses I put in have not leaked and look brand new.

From the Gates website:
› Works with multiple fuels: approved for use with leaded and unleaded petrol, diesel,biodiesel up to B-100, E-10, E-15, E-85, 100% methanol, ethanol and gasohol fuels.
› Best-in-class working pressure of 1.55 MPa (15.5 kg/cm²) and a temperature range of-40°C to 125°C continuous, up to 150°C intermittent.

[shogun]

Thanls for your info with own experience with the Gates Barricade.
Here a comment from an E31 840 owner, NashTom: I just finished restoring my fuel tank and had to research fuel lines. My generic conclusion is SAE J30R9 for non-submersion applications and SAE J30R10 for submersion - no manufacturer loyalty. With a special definition for the Gates hose. Specs as follows:
Copied from SAE J30R9 Specification-
Fuel Injection Hose Medium-Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R9).Hose primarily intended to meet the demands of fuel injection systems. These would include, for example, electronic fuel metering (EFM), electronic fuel injection (EFI), throttle body injection (TBI), and the like. Other areas of utility are those applications requiring fuel permeation resistance exceeding 30R8 and ones which require fuel resistance greater than that obtainable with 30R6, 7, and 8. Exposure of this hose to gasoline or diesel fuel that contains high levels, greater than 5% by volume, of oxygenates, i.e., ethanol, methanol, or MTBE may result in significantly higher permeation rates than realized with ASTM Fuel C. This hose may be supplied in either a coupled or uncoupled form, and is useful in the transportation of gasoline, ethanol extended gasoline, diesel fuel, lubrication oil, or the vapor present in either the fuel system or the crankcase of internal combustion engines in mobile, stationary, and marine applications. This hose has a maximum working pressure of 0.69 MPa (100 psi) up to and including 12.70 mm (1/2 in) ID. This hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in
normal operating temperatures of 34 to 135 °C (29 to 275 °F) and intermittent use at 150°C (302 °F).

Copied from SAE J30R10 specification-In-Tank, Low-Pressure, Uncoupled Fuel Hoses (SAE 30R10)
Hose intended primarily for use in fuel injection systems where the hose may be submerged in the fuel tank. The hose is capable of handling gasoline, alcohol-extended gasoline or diesel fuel used in mobile, stationary, and marine applications.This hose has a maximum working pressure of 0.69 MPa (100 psi) up to and including 12.7 mm ID. This hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in normal operating temperatures of 34 to 100 °C and intermittent use at 125 °C.

The Gates non-submersed is interesting since they specify a significantly higher working pressure (225psi/1.5MPa) and slightly lower (257f/125c) working temperature and say they exceed J30R14. This is typically a specification for small engines. Gates has well exceeded the working pressures of that spec which is 50 psi. The T2 part of the Gates spec is for a working temperature of 125c which is above the base J30R14T1 spec (below).

Copied from SAE J30R14 specification-Low Permeation, Low Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover Hose for Small Engines
(SAE 30R14)
Hose which may be supplied either coupled or uncoupled for use with gasoline, diesel fuel, lubrication oil, or the vapor present in either the fuel system or in the crankcase of internal combustion engines in small engine applications. Exposure of these hoses to gasoline or diesel fuel which contain high levels, greater than 5% by volume, of oxygenates, i.e., ethanol, methanol, or MTBE (methyl tertiary butyl ether), may result in significantly higher permeation rates than those listed for 30R14. This hose is for maximum working pressures of 0.34 MPa (50 psi) up to and including 9.53 mm
(3/8 in) ID and for hose in excess of 25.40 mm (1 in), the working pressure is 0.11 MPa (16 psi). The hose may be furnished in long lengths, specific cut lengths, or as a part preformed to a specific configuration. This hose is suitable for use in temperatures up to 100 °C (212 °F) for 30R14 T1, 125 °C (257 °F) for 30R14 T2.
My assumption is that since Gates uses a plastic inner liner on the non-submersion as opposed to FKM they have sacrificed a little on the upper temperature range 125c vs 135c in the R9 specification otherwise they would exceed the R9 specification. The plastic liner may also be the reason Gates calls out not meeting the kink resistance for 30R14T2. I do not know that this is correct - just my assumption.
I used Continental Elite that meets J30R9. Nothing wrong with the Gates since I do not think the fuel line is placed anywhere that would exceed 257f/125c and some may appreciate the higher working pressure. Funny thing was that I learned all of this when I was searching to purchase the Gates and could not easily find it when I needed it. I am certain there are also testing differences to meet each spec but it would be a full time job to get to that detail. If I am wrong on any point please correct me. Hate if I were to spread bad info. NashTom

[adrian0521]

I replaced my 8X13 fuel hose with CRP and it developed cracks all over in 1 year . It is terrible. It seams like no European alternative. I am going with Gates Barricade 5/16" as well.
Attachment 665327Attachment 665328Attachment 665326

[cartoonz]

the Gates Barricade hose is all I use now. Been there, done that - that hose holds up.

[JDP530]

I replaced all of the fuel lines with the Gates Barricade brand also.

[Timm]

Don't forget that OLD fuel will knacker the best of the fuel hose material - before it turns to varnish it turns into fuel-hose-eating-fluid.

Shogun posted this yesterday:

https://web.archive.org/web/20190128...icle-tanks.pdf

A quote from it:

Gum and Peroxide formation

With long storage periods, especially in the presence of hot weather or engine heat thepetrol can oxidize to form peroxides. These compounds can attack rubber and metal,stripping away the liner on fuel lines or copper from fuel pumps and attacking rubberhoses. These normally take a few months to form in sufficient quantity to cause aproblem. This process is faster if Ultra Violet light can get to the petrol.

[shogun]

Unicoil hose bending system is also nice, I bought some sizes http://www.gatesunitta.com/en/unicoi...bending-system
Now you can make those quick repairs when curved/molded hose is not available. Unicoil allows you to configure custom-bent hoses using straight hose. http://www.unicoil.com.au/
http://www.km5tz.com/images/850i/Fuel%20filters.JPG
http://www.km5tz.com/images/850i/90deghose.JPG

[letank]

thank you for BTT this topic.

yes hose is another 4 letter word, a few years ago I bought a fuel hose replacement from one of the on-line vendors for the 450sl, it has a sharp curve, the OEM was still bending but had cracked... the replacement upon bending, collapsed in the middle. I went to the local hydraulic hose manufacturer and ask them to remake the hose.

[kce1900]

Is the bad experience that adrian0521 had due to the manufacturer CRP or the spec of the hose? In his pictures we can only read "CRP Automotive Fuel Hose" but nothing else. FCP Euro is selling a CRP product that's labelled as FPM. I'm wondering whether that's any good. They charge $20/meter for this hose whereas their CRP made NBR material costs only $2/m.

[shogun]

That was probably a NBR hose, if the hose is cheap = then it is NBR and not FKM/FPM, CRP = Continental and they also sell FKM fuel hoses which are more expensive. But even in the ETK you have to be careful and check if it is FKM / FPM for the engine bay.
Confused now? The Difference between FPM, FKM, Viton
The terms FPM, FKM and Viton® very often cause confusion and lead to incorrect interpretations. All of these designations actually stand for one single base material: fluoro rubber.
FPM is the international abbreviation according to DIN/ISO, whereas
FKM is the short form for the fluoro elastomer category according to the American standard ASTM.
Viton® is the registered trade mark of DuPont Performance Elastomers.

[kce1900]

Here's a picture of CRP product ($20/m) that arrived today from FCP Euro. The hose is labelled on both sides, one side has the material spec (FPM) and the other side says BMW.
The hose comes in 1-meter pieces, so if you order three you will get three pieces. I was expecting a single 3 meter long hose. Not a problem, I need three pieces that are around 0.5 m and several short ones.

[shogun]

that $20/m is a bargain price for BMW CRP Continental FPM/FKM fuel hose 8X13MM 13537563456, BMW dealer in Germany sells that per meter for $59.95

[m60power]

Here's a picture of CRP product ($20/m) that arrived today from FCP Euro. The hose is labelled on both sides, one side has the material spec (FPM) and the other side says BMW.
The hose comes in 1-meter pieces, so if you order three you will get three pieces. I was expecting a single 3 meter long hose. Not a problem, I need three pieces that are around 0.5 m and several short ones.

Oh wow, that's an excellent find! A very good price for that hose type and it has the BMW logo on it. The Gates variant of fluorocarbon submersible fuel hose is like $30 a foot

[kce1900]

Disclaimer: I'm neither a chemist nor a materials engineer, just some bloke who sometimes succeeds in using a search engine.

Fuel hoses are constructed from different layers. The one that I bought is labeled >FPM/ECO/AR/ECO< which means that it has four layers. They are from the inside to the outside:

• FPM: Fluoroelastomer, a material that can handle fuels containing ethanol as well as bio-diesel, resistant to higher temperatures than NBR
• ECO: Epichlorohydrin rubber
• AR: Aramid protective braid
• ECO: Epichlorohydrin rubber

Other common hoses are >NBR/CR< which are made of:

• NBR: Nitrile butadiene rubber
• CR: Chloroprene Rubber

Neither of them is submersible! For in-tank applications you need a hose that has either FPM/FKM or NBR on the inside and the outside. The printing on the hose should clearly show this, for example: >FKM/AR/FKM< from Gates or >NBR/CO/NBR< from Cohline. (CO = cotton yarn)

Whether or to what extent NBR is suitable for modern fuels is actually debatable. Here's a datasheet from Würth that warns against using NBR for automotive fuels.

Another thing to look for is the pressure that the hose can withstand. My 750 has fuel pressure regulators maintaining 3 bar (43.5 psi). I've seen hoses for sale that are rated at 40 psi. No way!

Links: German page explaining fuels hoses, Index of elastomers

[m60power]

Ah, ok. Thank you for that clarification. I went and assumed the inside and outside layers were both FPM or FKM. Yeah if the other layers aren't the right material then it's definitely not a submersible hose. I would even argue that NBR is not good enough (at least based on my recent experience with the BMW NBR hose. It'll work, just not for very long. I would guess it's probably highly dependent on the exact manufacturing process quality / composition of the NBR too).