Fuel regulator hose replacement

I want to replace the fuel rubber hose that goes to the fuel regulator RH&LH , what pressure and temp that hose should support ?

When replacing any high pressure fuel hoses on my V12, I ONLY use Gates Barricade Fuel Injection hose.

Those fuel lines you’re talking about, how will you replace rubber section? Will you take it to someone who can rebuild?

I was thinking of doing it myself, how dangerous is it?

Its not a big deal. It is well described in Kirby’s book. Agreed on using the good Gates hose.

These next statements are going to cause a few heads around here to pop off, and several will likely chime in as to why it can’t possibly be OK. You can decide for yourself.

This fuel injection system only runs at 40 PSI. That is well within the acceptable range for using good hose clamps. You can cut off the “cups” used to crimp the hose on the fittings and replace them with fuel-injection style hose clamps. In fact, your car might already have a couple of hose clamps in place, like where the metal lines from the rear enter and exit the engine compartment.

IMHO the only reason for the cup fittings is because they do not need to be re-tightened. Hose clamps will after a few days, then they will settle down and be fine.

You can see an example of where I used hose clamps here on one of my fuel pressure regulators.

I DO NOT suggest this for the short hoses from the fuel injector rail to the fuel injectors. Get the correct hoses from @SD_Faircloth or whoever and do that part like it was done originally.


Those fittings are push-on hoses. You can tell because the cups aren’t crimped. They really just make the connection look pretty. Clamps – of any kind – should not be used on these hose connections. Find the correct size EFI hose – probably 5/16" or 3/8", that covers most fuel hoses on the XJ-S – and press them on, give 'em a tug to seat them, and forget about it.

Should you reuse those cups? If you can get the old hose off without damaging the cups, yeah, sure, put them back on while pushing on the new hose. I usually have to mangle that cup to get the old hose off, though. Some have reported success using heat, a soldering iron or perhaps a torch. Whatever, make sure the barbs are clean and unmarred before pushing on the new hose.

You absolutely can do it yourself. I have replaced ALL the rubber fuel lines on my car, including the ones in your photo. I, too, use the “Barricade” fuel injection hose. After you remove the metal cups, use a utility knife with a new blade to cut through the old rubber hose- but don’t use the tip of the blade. Turn the blade sideways and make slicing cuts rather like peeling an apple- a little at a time. Using liquid soap as a lubricant helps, too. If you keep the tip of the blade away from the barbed metal ends, there is less chance of damage. The only time I use hose clamps is on a non-Jag fitting, ie the “T” piece for a fuel pressure gauge. Seven years and no sign of a leak. You can test your work by clamping the fuel return line, which will allow the fuel pump to go to maximum pressure, and turn on the ignition without starting the engine. Just a second or two!

I use to do that as well. Changed everything to Gates Barricade which is fortune in Europe.

Now… Forget about Barricade - marine grade A1 is the new, best choice. If your pocket can handle this - A1-15 precisely, just released on the market due to more strict emission regulations. Lowest permeability (permeability = fuel smell) ever manufactured and able to be placed over the barbs.

You can find hose end fittings all over the Internet, same as the new hose end caps. Got 1kg of these for £20 in UK…

Not sure how that works in V12, however 3.6 / 4.0 looks like incest between stray dog and engineer - I have 3/8th hoses with metric threaded fittings…

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Gates Barricade is excellent, and it’s quite cheaper and easy to find here in the US.

I agree, got them on my car all-over. Paid much, MUCH more than Yankee would expect :wink:
Just saying that there is something much better released…

There we go, hose end fittings, whole bunch worth 1.5 pack of UK cigs:

The fuel line cups can be easily removed and reused if you cut off the bulk of the hose, and then torch the cup. When the remaining hose gets really hot it will literally “bloom” out of the cup as it expands and burns, You can pull it apart with your bare hands after it cools. The remaining detritus flakes off. Then just wire brush the old cup and metal pipe, maybe spray some silver spray paint on it, and you’re ready to go.

Using a small packet of Autozone Coolant Hose Lubricant makes putting the new hose on very easy…. Put the cup on the end of the hose, slide them onto the barb together. You can also use “red rubber grease”, which is not to be confused with red chassis grease, to lube it up a bit but that stuff isn’t too common in USA. Maybe even soap and water will be enough to get the hose on easily.

Hello John6 - I thought that the cup was intended to be used to keep the approximate last 3/16th of an inch, of the hose end, from expanding, which would allow possible movement of the hose to attempt to back off the barb fitting - if so, would this not make the hose hard to push down past the barbs when installing the hose, with the holding force of the cup at the end of the hose - apparently I must have the incorrect understanding view of the design of the hose/cup arrangement, from reading your posts - any explaination for correction will be appreciated - thanks, Tex.

You just might need a little lube to overcome the rubber on metal friction… makes it easier… no comment on actual design and theoretical reasons! Spit might work too!

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Years ago now I had a talk w/ Roger Bywater re. the design of the hose ferrules. I’m pretty sure I am remembering this correctly. He said the wedge shape of the ferrule forces the bitter end of the hose into a smaller circumference such that it helps clamp the hose to the ferrule. By squeezing the OD of the hose inward and upon itself, it squeezes the ID of the hose onto the hose barb for a tighter fit. This from they guy who was actually there during the design of the engine. Not sure why other folks still say they have no purpose other that to look pretty. SD Faircloth www.jaguarfuelinjectorservice.com


Fifty years ago I started working at a pipe manufacturer. After the steel pipe came out of the furnace, it was finished and tested by machines run by air pressure exceeding 100 psi.
The air lines to these machines were push-on, and the fittings had the typical metal cups, or ferrules, we see on our fuel injection lines.
In the 80’s, IIRC, the metal ferrules were discontinued, and plastic became their replacement. Cost, I suppose. Sometimes I would use one of these fittings in my shop, usually for an air line, and I never saw a failure because of the change from metal to plastic. It became clear to me that there was no advantage in having any kind of a ferrule at the end of the air line, but it looked “neater.”
When I replaced the F.I. hoses on my car, removing the metal ferrules to get to the end of the hose was a pain. Because of my forty years of dealing with such things when I had to work, the ferrules were not replaced. None of my fuel lines have leaked in six years, no smell, nothing.
About a year ago, by chance I discovered that Mcmaster sells the plastic ferrules I was familiar with , and I bought some to see how they would look. One quick slit with a sharp knife, and they can be put in place without any disassembly. Purely dressup, nothing more.
The photo shows a typical brass fitting from last century, and the yellow plastic ferrules. If you look closely at the location of the barbs on the brass fitting, the ferrule would have no clamping action on the rubber hose, as it is simply too far away from the barbs, where the actual sealing takes place.
There are three choices. Buy new, or re-use the metal ferrules. Have no ferrules at all. Use plastic ferrules, just like the people who make such things for industry. A good clean cut at the end of your new fuel hose, and it won’t know the difference.
BTW, Mcmaster calls these things “locking rings.”

Ferrule with snug fit over the barbs makes some difference, not sure it is actual performance difference or additional safety difference.
Not long ago I have assembled new high pressure fuel line to replace the one in my AJ6 (same rules apply to v12). Due to the quality issues with these days products - I’ve picked marine A1 hose and pressure tested it with compressed air as seen below. I am aware that test with actual liquid would make the hose burst in lower pressure range, but still better than nothing:

The spec of marine hose shows burst pressure at 20bar but i was unable to burts the hose at all due to naturally implemented design barrier - leaks.

The hose was first pressure pumped with one end over the barb blanking fitting and started to leak the air at 8-9bar, again this was air, not liquid so assumingly that wouldn’t happen with petrol.

Then the snug fit (by hand) ferrule was added and the leak pressure got up to approx 13-15bar:

Still, the working pressure of EFI system is 3bar so is it worth a hassle?
Assuming that the fuel system is blocked or kinked somewhere - the actual hp side pressure could probably go up to 8-9bar with genuine fuel pump…

Anyway, additional efi clamps over barbs were placed in the final part of experiment. Unfortunately even with clamps the leaks were massive and I was able to hit only 65bar /1000psi barrier without burst. That’ 3 times higher than declared burst pressure from manufacturer.

It is worth mentioning that these days manufacturers are quite relaxed with barb manufacturing, the tolerances may be all-over and the barbs may be simply too rounded…

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What size hose is the suitable replacement for the ones in Shahar Alon’s pic?

5/16 I.D. Many of us here in the States like Gates barricade F.I. hose. Readily available.

This past winter i replaced all my fuel hoses on my 89 v12 with napa lines ,i also used fuel injection clamps on all hoses including injectors . I have had no leaks . I think if you buy a good quality hose you will be ok . Just take your time . Some times people make it harder than it has to be in my opinion…

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The shorter one is 3/8th not sure e
Why longer one could be 5/16th…? as it is 3/8th as well on AJ6 engine…