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George Eagle
United Kingdom
3244 Posts |
 Posted - 16/08/2007 : 21:11:04
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I have fitted stainless steel braided hoses to my blown NB and have experienced no problems until this year - the car was put back on the road about 7 years ago following a total rebuild.
I have a low pressure Facet petrol pump mounted beneath the floorboards on the drivers side and this feeds the front mounted supercharger. Earlier this summer the hose connecting the pump to an in line fuel filter suddenly failed with a major leak. I thought this was a "one off" and replaced it. Last weekend the hose from the petrol tap (which has main and reserve connections) to the pump also failed with a major leak. Could have been an embarrasment as on the prior weekend I drove a round trip of 120 miles to VSCC Prescott and thought the fuel consumption was high! I almost ran out of fuel despite the standard 2 gallons in reserve in the tank.
Has anyone else encountered problems with the braided type of flex hose? I have now heard that others have experienced problems. The problem has been the actual hose and not the 1/4 inch bsp connections.
Perhaps it is the modern unleaded petrol that is too corrosive, I also use Castrol Valvemaster plus additive.
George Eagle.
NA0960 |
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Mike
United Kingdom
229 Posts |
Posted - 16/08/2007 : 21:26:13
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George,
I had a similar problem with my 1972 MG Midget about 5 years ago. The car had a total restoration and one of the items renewed was all the braided fuel hoses. After some 12 months I was going on a rally and noticed how quick the fuel gauge was dropping. I stopped and lifted the bonnet and the braided hose from the copper pipe to the fuel bowl was like a watering can, spewing fuel out everywhere.
Back in the garage I removed the hose and peeled back the braid and found the rubber hose had just crumbled apart. Checking the braided hose from fuel bowl to fuel bowl showed similar but not as severe break up.
I concluded that the feed hose from the copper pipe to the engine took more flexing and coupled with un leaded petrol had caused the failure.
I contacted Burlen and bought replacement braided hoses as they said they were resistant to un leaded petrol. I used the same on my MG NA and after 7 years the NA is still okay as is the Midget.
Having said that I check the hoses regularly as my Midget could well have caught fire. I remember too how un leaded petrol attacked the rubber gaskets around the filler neck of both my wifes and my Ford Sierra`s and the Ford agent said it was due to un leaded petrol attack.
M ELLIS |
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bahnisch
Australia
674 Posts |
Posted - 17/08/2007 : 04:06:51
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| I have been told that infrequent use compounds the problem and that the hoses survive longer if constantly "wet". I think that there are newer types of "inners" that are resistant to attack? |
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Bruce Sutherland
United Kingdom
1579 Posts |
Posted - 17/08/2007 : 11:48:06
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Hello George,
There are 2 types of fuel hose currently used by major vehicle manufacturers:
1) EPDM lined with Viton with a braided reinforcement extruded within the the EPDM - ContiTech (Germany) & Aeroquip make these.
2) PTFE with an outer stainless steel braiding - EuroPower Hydraulics, Beverley, Yorkshire make these.
The PTFE varaint is used to resist the very high pressures in some modern fuel injection systems.
Notes
(a)That any externally braided stainless steel is NOT good at resisting chaffing, so care must be taken to make sure that the braid does not touch anything sharp/metallic including another braided hose - protect with rubber gommet or similar.
(b) Hoses (all types) should never be installed in a twisted condition - allow them to take their 'natural' routing. Adjust the length of the hose and/or the orientation of the mating hose end fitting to get the 'run' of the hose correct.
Hope this helps.
Bruce. |
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Bob Clare
United Kingdom
278 Posts |
Posted - 18/08/2007 : 10:58:46
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Hello George and other leakers,
Last summer I exchanged a long series of conversations with Mike Dowley on this topic and he supplied me with replacement hoses which so far are OK. Suggest you chat with him.
Bob Clare |
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talbot
United Kingdom
718 Posts |
Posted - 18/08/2007 : 12:16:52
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I got a set of brake and fuel hoses for my MG TD made up at a local Pirtek franchise. They had a range of materials, including braided, and were able to use my BSF fittings. Best of all their charge was very reasonable.
Jan T |
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JohnSteedman
United Kingdom
41 Posts |
Posted - 18/08/2007 : 12:26:11
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I had exactly the same problem this year with both fuel lines on my TC, which I had purchased in 2002 from a stand at Silversone. I started the engine after the winter lay-up and found that several pin-holes in the rubber were spraying fuel all over the exhaust manifold!
John
TC0301, J0312 |
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Terry Andrews
United Kingdom
546 Posts |
Posted - 18/08/2007 : 13:26:57
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Dear Owners of Incontinent Cars
I personally have not suffered from this problem! However, I know many people who have. Bruce is in a better position to know about these things. I was told that on the gradual change over to unleaded fuel there were compounds that affected standard petrol hose material. I was also told by someone in the trade that to differencing between different types of hose material which is covered with SS, a tracer colour was introduced e.g. blue, yellow and red. This started about the late 1980Æs to early 1990Æs. So when I built our TF 1500 I was advised to fit pipes with red tracer within the SS braiding. I also changed all my hoses on the P type when I re-commissioned it 4 years ago.
PLEASE ALSO BE AWARE THAT THIS ISSUE ALSO AFFECTS THE DIAPHRAGMS OF SU PETROL PUMPS !!!!!!!!!!
Various other Classic car web sites have warned of this. I think all Diaphragms supplied after 1999 should be OK. So I have changed all my diaphragms on my current running cars.
I would be interested on BruceÆs comments on any of what I have written or the quotes from other sites.
Regards Terry
Old Blog
For the first time in some 35 years messing about with old cars I've just had an SU electric fuel pump diaphragm fail on my MGTA. I noticed an oily drip under the Bakelite end cover. On removal there was petrol inside the cover. I hadn't thought about where the petrol goes if the diaphragm ruptures. If the pump is mounted horizontally, as on my MG, then the petrol goes through the hole in the centre of the coil housing and into the end cover where the contacts are arcing away ready to ignite it. I have not decided what to do apart from fitting a new diaphragm, but contact less switching is a possible.
As a side issue the failed diaphragm, which was about 2 years old, appeared to have dissolved in the petrol leaving bare canvas visible. Anyone had any problems with unsuitable materials on SU diaphragms? I hope nobody has any nasty accidents due to this problem.
QUOTE: Burlen took over production of SU Fuel Pumps about two years ago and immediately introduced a program of development to ensure the compatibility with modern aggressive fuels. The old three layer diaphragm was replaced by a modern material (American manufacture) using two layers.
There are large stocks (ex military) around the world of old type diaphragms and these are not likely to be modern fuel resistant. To be sure use only genuine SU spares manufactured by Burlen in the last two years. |
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Malcolm Bailey
United Kingdom
301 Posts |
Posted - 21/08/2007 : 19:08:23
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Thank you Terry for the tip regarding fuel pump diaphragms. I spoke to a very knowledgable chap at Burlens this afternoon and he sold me Pre 1985 Pump repair kit for my 1934 ND. The kit comprised the diaphragm and various other bits including the armature guide, filter, spring, points and blade all for ú24.84 plus VAT. He assured me that the present diaphragm material had been specially produced to cope with modern lead free fuels but I did not get any technical details.
Thanks George for the original question. I do find this forum invaluable which is only because those among us who are knowledgable are prepared to go to some trouble to share their knowledge with us.
Malcolm |
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David Allison
United Kingdom
665 Posts |
Posted - 22/08/2007 : 08:55:47
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As an engineer working day to day with hydraulic hose - i can not really spread much light on your fuel problems - except that the chemical make up of un-leaded fuel has changed a great deal (as has hydraulic oil)and hose failures are becoming more common.
One of the correspondants states the fact regards the hose must be installed carefully - and while this sounds a bit obvious, you would be suprised how many hose installations ignore this.
Braided hoses are designed to transfer pressurized gas or fluid with less expansion (this is the only real reason for using it) than standard rubber hose, yet still offer the flexibility.
The real reason for using braided hose for under bonnet installation is aesthetics! - it looks nicer than black hose.
You must be careful to purchase all braided hose from a recognised supplier and be careful to state what the hose is to be used for.
Many aftermarket suppliers simply buy hose from cheapest supplier (and use the Aeroquip name as a generis for all braided hose), these suppliers are unaware of the installation or application, they just make to a price.
Gentlemen dont scrimp - go to your local hose supplier Pirtek, Hosemaster, Aeroquip, Sports & Vintage, Unimaster (are in Newbury well recommended).
These guys specialise in this stuff and can often recommend a better product than the aftermarket people.
Dont be alarmed if the product they recommend is sheathed in black rubber (it might not look as nice)as this might be the best solution - if you insist on the shiny stuff they can supply this too - also they can supply all the hard pipe and fittings, including silver solder.
Sorry this is a bit long winded - but braided hose I know about.
PS- The fuel companies are lying about fuel quality and almost everything else, they change their brews like the wind to suit their profit margins! |
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