You may recall that I had a rant about rotting flexible fuel pipe a while ago (LINKY).

In the end I did a lot of internet research, and came up with the following observations:

Background

* Since getting my car on the road 7 or 8 years ago I have had to replace rotted flexible fuel hoses 3 times. Each time the hose has cracked and was dripping fuel everywhere.
* I have always used decent quality hose (Gates, or similar).
* It seemed to happen randomly but especially after a long spell in the garage, whether due to bad weather or whatever. (significant point #1)
* Some other people had similar problems.
* More people were using similar hose and having no problems (significant point #2)

Results of research

* Petrol has changed significantly over past few years - it now contains more alcohol-based substances, which are very corrosive to normal rubber.
* Hoses in the USA are marked with an SAE code, e.g. SAE J30R9, according to its ability to resist modern fuels. As much of the hose bought in the UK is made (or sold) in the USA then these markings may appear here.
* There are 4 significant groups of SAE codes:
Unmarked hose - will probably be for the original petrol formula, without modern additives (but see later comments).
30R6 - This is the standard for the petrol formula of 5 - 10 years ago, for fuel injection. The bore may or may not be lined with Nitrile.
30R7 - This is the standard for the petrol formula of 2 or 3 years ago, for fuel injection. The bore is lined with Nitrile.
30R9 / 30R10 - This is the current standard. The bore is lined with Fluoroelastomer/Nitrile. 30R9 has Fluoroelastomer/Nitrile on the inside, while 30R10 has it inside and out, which allows it to be used immersed in petrol (e.g. in a fuel tank).
* There is also a marine grade for use in boats - ISO 7480 A1 - that is roughly equivalent to 30R7-and-a-bit, with added fire resistance.
* One of the causes of fuel pipe failure described in the USA literature is stale modern fuel, not so much the fuel itself. These fuels become extra-corrosive when they get old.
* The USA seem to use a higher percentage of alcohol in their regular fuel - but we're not far behind in Europe.

What got me angry...

* Gates in the USA only make and sell fuel pipe of grade 30R9 or better (they even have brand-new super-grades). Gates in the UK distribute unmarked hose to motor factors that, if you are lucky, is only 30R6. Why don't we get the same? Are they dumping their surplus stock on the UK?
* The Gates sales rep for the UK and Europe didn't know that the USA grades were far higher than his offerings - he didn't even know the trade names for the USA products (shown in every USA Gates catalogue).
* 30R9 is freely available on the USA ebay, at sensible prices, made by big-name manufacturers such as Gates and Goodyear. It is never (or maybe rarely) available on the UK ebay. Only the excessive postage stopped me from buying it there.
* One on-line supplier (Think Auto) advertised that their hose is 30R9, but when it turned up it was unmarked. I recognised that it was stuff that I'd used previously and told them so. To their credit they apologised, refunded my money AND paid for the return postage.
* There is a general ignorance about this whole issue - when I asked for a specific grade of hose many suppliers didn't comprehend, while others were almost abusive ("Our stuff is good enough...!).
* The one who did supply the correct hose, Hose World, advertised it as 30R10 on their website, the bloke on the phone didn't think it was any special grade when I asked, and when it turned up it was 30R9, which is what I was after in the first place!
* If you search on any USA car forum about fuel pipe you will see that most people are fully aware of this issue, and the need to use modern hose. There seems to be a general ignorance in the UK.

Last thoughts and recommendations

It was almost certainly stale fuel that rotted my fuel pipe(s).

1. Don't buy general-purpose hose from a motor factor, unless it has at least 30R9 printed on it. Even stuff off the Gates stand isn't good enough.
2. If you are getting it via the internet or mail order, don't be fobbed off by excuses. Only the proper stuff is safe for long-term use.
3. If you are going to leave your car unused for a month or so, consider draining the petrol, especially if you are unsure of your fuel pipe grade.
4. If you really can't get 30R9, consider getting ISO 7480 - this is easily available from marine suppliers in the UK (but see point 3). All proper fuel pipe in this grade has to be marked, to meet regulations.

Additional thought

Re-reading some of the websites I found during this research reminded me of an important indication of fuel pipe decay - smell.

If you go into your garage and there is a stink of petrol, but you can't find a leak, then it is very likely that vapour is permeating through the fuel hose. If this is the case then it is a fair bet that the hose will fail sometime in the near future... maybe not immediately, but sometime.

[Edited on 5/4/11 by David Jenkins]

Very interesting research! Kind of makes sense about the old fuel I suppose. The alcohol probably oxidises into all kinds of acidic nastiness. I could vouch on Sunday morning that an excess of old alcohol based fuels is not a good thing

Thanks for that - its a good summary. There is a lot of concern in the classic car world about this at the moment, as they are the sort of cars that sit around for a while, and often have older fuel systems and older piping. There is even concern that some old copper fuel pipe may not be sufficiently resistant - that sounds a bit of an overreaction to me, but it certainly will affect diaphragms in fuel pumps and carbs....

Oh yeah, and it will knacker brass fittings as well...

All in all, a pain in the arse.

Chris

[Edited on 4/4/11 by chrsgrain]

Interesting. Many thanks.

I have a long run of rubber hose (Gates but not sure on its markings) which I know I need to replace with hard pipe post IVA so will be having a good look at it this week.

I can imagine my local motor factors reaction if I ask for a certain grade......miserable sods at the best of times.

Rich

Kunifer plus shortest poss lengths of rubber sound sensible - ideally in easy to access / inspect / replace places.

What do OE's use?

Excellent post, this really needs to be stickied.

quote:

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Originally posted by DarrenW
What do OE's use?

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quote:

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Originally posted by BenB
I could vouch on Sunday morning that an excess of old alcohol based fuels is not a good thing

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quote:

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Originally posted by DarrenW
Kunifer plus shortest poss lengths of rubber sound sensible - ideally in easy to access / inspect / replace places.

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quote:

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Originally posted by DarrenW
What do OE's use?

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Thankyou for the excellent and informative post David!

Bit worried about my Locost now which has been sitting for 3 years!
The long run is that expensive plastic coated ali stuff sold by Tifosi but the rest is probably Gates at the rear end and metal braided rubber at the front sold by Tifosi... so could be anything! lol

And my Mk2 Golf'a been sitting for 1-2yrs!

Cheers,
James

Great info
What I can't understand is why the flexible rubber hose fitted to production cars and bikes evn at nearly 20 years old does not have these problems?

10 mm nylon fuel line 7.5 metre length on eBay (end time 30-Apr-11 10:44:22 BST) is the stuff many OEMs use, I did ask about modern fuels, here's the response:

Hi Pete,
Thanks for asking.

Our supplier has been supplying fuel and hose products for 30 years, and states that this problem does not apply to his nylon fuel line, there can be problems with rubber hoses with modern fuel, but we don;t sell rubber hoses. SUpplier confirms there is no degradation even with 100% ethanol fuel in the nylon hose we supply.

Hope this is OK for you and look forward to receiviing your order. We can supply in 100 ft lengths as well if you are interested.
Best Regards
James

That looks like interesting stuff. I wonder what the internal diameter is - any idea?

OOPS! Just spotted "8mm internal" in the advert!

[Edited on 4/4/11 by David Jenkins]

quote:

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Originally posted by ReMan
Great info
What I can't understand is why the flexible rubber hose fitted to production cars and bikes evn at nearly 20 years old does not have these problems?

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That's what puzzled me originally - different people get different results. I think that there are several factors involved: for me, I think the biggest is that fuel sits in the rubber pipes next to the tank for long periods, and gets stale. Those pipes rot, but the ones up by the carbs don't because the fuel drains back from there when the engine isn't running.

As for OEMs - most cars I've seen have hard piping from the tank right up to the engine compartment, so maybe the rubber tubes rarely sit filled with fuel for long periods?

This is why I put "for discussion" in the title of this thread!

but short 6" sections of rubber hose are surely 'as likely' to rot as a rubber fuel line from tank to carb?
in the next few weeks i'm doing mine with nylon pipe anyway. as much as i can...

quote:

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Originally posted by Mr Whippy

quote:

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Originally posted by ReMan
Great info
What I can't understand is why the flexible rubber hose fitted to production cars and bikes evn at nearly 20 years old does not have these problems?

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hmm and I use fuel hoses that are from the 70's and are still fine

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I haven't come to this conclusion all by myself... here are a few links on this subject (I can't find my original collection found while researching).

VolksBolts
ClubCobra

There was also a video produced by Gates, but I can't find a link to that any more...

And this one - but there is NO EVIDENCE that this was caused by fuel-affected fuel pipe - makes you think though...

MX5

[Edited on 4/4/11 by David Jenkins]

I have added an "additional thought" to the original post - I had forgotten to list a very important clue that can indicate whether your fuel hose is at risk - smell.

If your car pongs of petrol every time you go into the garage, but there's no sign of a leak, then it's probably due to vapour permeating through the hose. This permeating vapour is what destroys the outer casing of the hose over time.

Since this problem was first posted I have kept a regular check on my hoses. I have checked them again today and they all look fine, no cracks, no leaks and no smell. They have been in use since around 2004/5, so 6 or 7 years, so I thought it worth posting some details of the hose here.

It came with the new carburettor I bought from Southern Carburettors in April 2004 and he markings on the hose are:

Webcon UK BE 4012 WP Leaded/Unleaded 7,4 3Q01

I've got the Nitrile lined stuff sold by my local hydraulic hose supplier and apart from an overtightened jubilee clip which split one hose (since changed to spring clips) all has been fine for 5 years. I'm not sure if it's relevant but I have always used 97RON fuel - maybe it is less aggressive to hoses?

Perhaps my next bit of research should be to investigate why people get random results with their fuel hose!

Seriously though... there are significant numbers of people who have experienced rotting hose, and a large group of others who have no problems.

Maybe there are mechanical factors (hose clamps, as in RazMan's post) as well as chemical ones?

i had a BMW 318 (E30) and kept splitting fuel hoses, in a matter of days
think it was conneced to the redex i was using. when i stopped that it was fine

My hose clips are like these

http://www.jetpress.com/Products.aspx/17210/HoseClamps/HoseClipsRatchetType/

again supplied with the carburettor.

PS For some reason I am not able to add pictures to posts.

quote:

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Originally posted by r1_pete
10 mm nylon fuel line 7.5 metre length on eBay (end time 30-Apr-11 10:44:22 BST) is the stuff many OEMs use.

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Ok done a bit more research on the nylon pipe, and this site came up from a thread last year, might be useful to someone.

http://www.tinleytech.co.uk/acatalog/Poly_Pipe__Clips_and_Fittings.html

As I said before, do not use LPG hose for petrol. LPG is far less aggressive than petrol. Also. The couplings in that link are prone to blowing off at higher pressures. I'd avoid them like the plague!

The best solution seems to be to use proper hose as per OP

I have used this type of fitting(http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1825333) for emergency repairs to plastic fuel pipe and had no problems. As they are intended for airlines they are designed to run at a higher pressure than the fuel systems, you can succesfuly join plastic to plastic or plastic to metal, i don`t know how they perform under long term exposure to petrol though.
keith

Thanks for the info David, we've had the same problems with dodgy fuel pipe, it's good to know there's a fix
The vague smell of petrol just reminds me of the pictures on here over the years of peoples pride and joy going up in flames as they watch, admittedly it's only happened a couple of times but it's enough to prey on my mind.

I ordered 2m of 7.6mm J30R10 from Hose World a couple of days ago, this morning I received 2m of 1/2" hose with J30R7 stamped on it...

I've fired off an email, we'll see what they do to fix it

Best bet is always Teflon hose for fuel supply.
I use AN Motorsport a lot for hose supplies and fittings http://www.anmotorsport.co.uk

Viper offer a very good VFM Teflon & Stainless Steel outer braid hose.
http://www.viperperformance.co.uk/productsearch.php?xscId=9816

What pressure does the Viper hose stay safe to though? Couldn't see any ratings or mention of Injection, just carbs?

Very interesting! Just went to the garage to take a look at the hose I purchased.

Turns out its DIN 73379 which is the same as 30R7, so I suppose not too bad.

Point of note, this is Goodyear fuel hose purchased from Halfords, and it's cheaper in Halfords than anywhere online (£3 a meter, about £2.60 with trade card), so I'm impressed that it's not "unmarked". You have to ask for it at the parts counter and apparently a lot of stores are no longer stocking it, but it's good stuff!

quote:

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Originally posted by flibble
What pressure does the Viper hose stay safe to though? Couldn't see any ratings or mention of Injection, just carbs?

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As a add on to this post....
I have used for the last 4 years on my car black plastic air line pipe from HGV trailers (i believe it is made from ptfe) in two places i have added spedifit snap connectors to enable easy removal of the engine and/or carb. The connectors are air tight so end up fuel tight as well. There is no visible deterioration of the pipes or the connectors and after 25000 miles i have had no problems including driving on the roads in France around Paris on one of the hottest days of the year in rush hour traffic (over 30 degrees)

While I was in the USA recently, I ventured into auto parts store to enquire about fuel hose. After much deliberation, I came away with five feet of hose marked with this …

GATES FUEL INJECTION HOSE 5/16 INCH (7.9 MM) 225PSI WP BARRICADE TM GREENSHIELD TM TECHNOLOGY

MULTI-FUEL & BIO-FUEL COMPATIBLE CARB No. Q-09-019 4219BF EPA 40 CPR 1051.110 CARB No. Q-09-019 MADE IN USA CS031711 X7 13:11

Here’s a link to the brochure about this

http://gates.com/brochure.cfm?brochure=12468&location_id=5348" target="_blank">Ga tes Barricade brochure

In the brochure is the claim “Exceeds SAE J30R14T2”. The manager in the store said that it therefore exceeded SAE J30R7 and 9.

I hope this is useful!

Geoff

if only they would sell it in europe i wouldnt have to change my hoses every few years

We needed some fuel hose because the stainless steel braided PTFE fuel hose we originally used, had started to decay and I remembered this post from a few years ago. A quick trawl on e-bay revealed this stuff: eBay Item

Ordered a couple of metres and although it doesn't look as good as SS braided hose, it is rated J30R9 so should last a bit longer and hopefully stop the smell of fuel when the garage door is opened.

Phil

quote:

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Originally posted by r1_pete
10 mm nylon fuel line 7.5 metre length on eBay (end time 30-Apr-11 10:44:22 BST) is the stuff many OEMs use, I did ask about modern fuels, here's the response:

Hi Pete,
Thanks for asking.

Our supplier has been supplying fuel and hose products for 30 years, and states that this problem does not apply to his nylon fuel line, there can be problems with rubber hoses with modern fuel, but we don;t sell rubber hoses. SUpplier confirms there is no degradation even with 100% ethanol fuel in the nylon hose we supply.

Hope this is OK for you and look forward to receiviing your order. We can supply in 100 ft lengths as well if you are interested.
Best Regards
James

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25m of Gates Barricade can be imported to the UK for £44 per 25' Reel. Works out at £5.77/m which seems ok in my book and I am sure you could resell any length leftover afterwards. It is fully ethanol compatible and claims to have the lowest permeation in the market.

I have some on order, just thought I would share with fellow LC'ers.

See: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110986471339

[Edited on 13/8/13 by Rob55]

quote:

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Originally posted by Hellfire
We needed some fuel hose because the stainless steel braided PTFE fuel hose we originally used, had started to decay and I remembered this post from a few years ago. A quick trawl on e-bay revealed this stuff: eBay Item

Ordered a couple of metres and although it doesn't look as good as SS braided hose, it is rated J30R9 so should last a bit longer and hopefully stop the smell of fuel when the garage door is opened.

Phil

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Fuel hose

As well as posting and lurking here, I have an interest in classic cars. They also have the same problem with fuel hoses. There are many reports of 'rubber' fuel hoses rotting from the inside out, mostly from close to the fuel tank rather than the carb/engine area. As has been said already it's worst where the fuel sits in the hose whilst a car is in storage.

One of things that it took me some time get, was the the higher the SAE number doesn't necessarily mean the better the hose. It seems that the SAE codes also take into account internal pressure rating. R7 is OK for ethanol fuel in carbs of all types as the fuel pressure is fairly low. By comparison R9 has the same level of resistance to ethanol but is rated for high pressure fuel injection systems. R10 is for diesel type fuels with a 'bio' content. R6 has a low pressure rating and a little resiststance to ethanol.


This is a link to a page on Goodyear hoses.

http://www.veyance.com/ProductListing.aspx?folderid=1036

In my simplistic view, my rule of thum is;

1. SAE R9 good for fuel injected engines with fuel up to around an E10 rating (10% ethanol).
2. SAE R7 good for carbed engines with fuel up to around an E10 rating (10% ethanol).

There is a really good piece of research at the FBHVC website here, which looks at how fuels affects all elements of the fuel system, including plastics and metals. It also reviews the effect of some the inhibitor additives that can be used to slow down the effects of modern fuels. Long and detailed but very informative.

http://www.fbhvc.co.uk/legislation-and-fuels/fuel-information/

R6/7/8 is low pressure for carb engines (not biodiesel) - differing temp ranges.
R9 is high pressure for injection systems (inc biodiesel)
R10 is low pressure "in tank" hose

From the SAE pages, not Internet myth

http://www.volksbolts.com/faq/SAEJ30.pdf

First time out this year my fuel pump decided to stop working leaving me to the mercy of the RAC. While it was up on stands it made sense to change the 12mm hoses from the swirl pit to the HP pump since they were due to be changed over the coming winter. Experience has shown that 4 years is long enough for these cotton braided hoses with modern fuel even if the DIN on the hose is equivalent to R7 hose.

Sytec don't sell hoses now so I bought some Cohline with the same DIN number from Advanced Fluid Solutions.

When I took the 3 year old Sytec hose off I expected it to be slightly hard but in fact it was still flexible and there were no cracks even were it goes over the swagings. Very different to previous hoses I have used, shame they don't do it any more, looks like it was working fine.

So its fingers crossed for the Cohline now.

Now for the worrying bit.

At the kit car show there were several stands selling R6 hose as "suitable for all modern fuels" which it clearly is not. How do they get away with it?

Hi guys,

I can now get in the UK SAE J30R9 at £6.64 per meter.
Guess this solves the leaking rubber pipe issues?

Not really, not unless its made by Gates.

I bought some of the eBay R9 fuel pipe and it was very very perished after 1 year.

The CoDan pipe seems to be recommended as good R9?

Managed to get some SAE 30R14 T1 from Gates so hopefully that will suffice lol

Where are people buying fuel pipe from and how much?

(Yes yes thread reserection - sorry but Adobe if you bought a year ago)

I've been using Car Builder Solutions, they have Gates R7 but also have Cohline ethonal proof pipe which i've been using which is still soft and flexible like new after a couple of years. It's not cheap though.

Unlike some i bough of ebay a few years ago, supposed to be top spec and gates...obviously wasn't as it was rock hard after 10 months and starting to perish/leak!.

I thought this excellent thread was worth resurrecting in light of a recent post and introduction of E10.

Would anyone who (unlike me!) knows what they're talking about in this field be able to update it please?

Thanks,
James

Good point & timely as I'm close to plumbing in fuel pipes. I've got R9 from a hopefully reputable supplier (twice cause I've taken so long I forgot I had any, only found the first lot when I went to put away the second lot!)

I'm hopeful R9 is still valid.