Fuel line connection at the tank

[ed8die]

I would like to paint my fuel tank and treat it against corrosion.
To remove the tank I would need to disconnect the fuel pipe at the tank.
I know that there is a pickup pipe inside and I understand the male/female connection with nut and olive (…) where the fuel line attaches to the tank, but what will happen if I disconnect the nut at the tank, will the pickup pipe remain at the joint or will it drop inside the tank nowhere to be found again?
Not sure what to do?

[philthehill]

Just undo the pipe nut and remove the tank.
You will not effect the tank internal pick up pipe by removing the pipe from the tank. The tank internal pick up pipe is permanently attached to the tank so no problems there.

[ed8die]

Thanks for you clear answer.
I dare to have a go at releasing the nut now . . .

[Murrayminor]

Thanks for you clear answer.
I dare to have a go at releasing the nut now . . .

Be careful you may twist the fuel pipe as you try to undo it.
I would suggest a decent penetrating oil (not WD40) on the nut beforehand, maybe even a day or two.

Then attempt to tighten the nut before attempting to undo it, tightening it may must break any rust free and then work it fore and aft slowly undoing it, but above all making sure the actual pipe doesn't twist and fracture.

Good luck.

[philthehill]

Use a 15mm pipe spanner of the style in the link below. Whilst the nut is 5/16" whitworth the 15mm spanner is a better fit on the nut.
Use a 6 sided spanner as the load is spread better. As above soak in penetrating oil. Do not overdo the untightening as you could cause the tank fitment to fail.
https://www.ebay.co.uk/itm/SEALEY-Flare ... %3A2334524
This is what you will be trying to undo:-

Tank union.JPG (1.34 MiB) Viewed 2980 times

[ndevans]

I'm going to have this problem shortly. Is the nut on the inside of the tank? Is it under the sender unit? As far as I can tell, there is no nut accessible on the outside of the tank.

[oliver90owner]

I'm going to have this problem shortly. Is the nut on the insider of the tank? Is it under the sender unit? As far as I can tell, there is no nut accessible on the outside of the tank.

Read Phil’s post on 04 Nov?

[ndevans]

A picture says a thousand words. There doesn't appear to be a nut on the pipe where it goes into the tank.

IMG_20201126_084311373~2.jpg (952.07 KiB) Viewed 2808 times

[philthehill]

I hope that I am wrong - but looking at the picture I would suggest that the head of the nut has been sheared off.

What you can do is cut the fuel pipe at suitable place and re-join with a piece of ethyl resistant rubber pipe.

[ndevans]

I hope you're wrong too! I replaced the fuel line about 10 years ago, I'm pretty sure I did the whole thing, not just the section under the car. It already has a section of fuel hose in, which I was hoping to replace with a single line, but if I can't get this out, then I'll have to be content with replacing the hose. The line got cut when I had some welding done some years ago-I remember them saying they had difficulties removing the pipe, so cut it and put fuel hose in. It's not a issue, I can replace the hose-but obviously that's not going to last forever, better to have a single copper line all the way.

[oliver90owner]

better to have a single copper line all the way.

Perhaps better to have a single line all the way. Admittedly my recent vehicles have been diesels, but they have had predominately plastic fuel lines for the last 25 years or so.

[geoberni]

better to have a single copper line all the way.

Perhaps better to have a single line all the way. Admittedly my recent vehicles have been diesels, but they have had predominately plastic fuel lines for the last 25 years or so.

I've had plastic fuel line on petrol cars, but they've all been very hard plastic in shaped lengths to suit the vehicle.

[philthehill]

If they had to cut the pipe to remove the tank that is a good indicator to the head of the nut being sheared off.
The thickness of the brass nut at that point is very thin and gives very little resistance to shear.
There are some good long life rubber petrol pipes out there.
This is the fuel pipe I use:- https://www.merlinmotorsport.co.uk/p/hi ... =2240-0600

It can also be purchased with a braided cotton sleeve.

[ndevans]

I don't have any SAE J30 R9 spec hose to hand, but I do have some R6, which will have to do as a temporary fix. Cheers N

[ndevans]

So, having spent the best part of the afternoon cleaning the fuel tank, making a new gasket for the sender, fitting the tank back in to the aperture in the car, and applying Kent seal'n'caulk (think Dum-dum in long strips), I then went to reconnect the two pieces of fuel line with a piece of hose. I had to wiggle and bend the stub of pipe on the tank to clear the back axle, as it had got caught and pushed round as I put the tank back in. As I did so, it went very floppy. I could turn the pipe in the tank, and a couple of short tugs freed it from the tank completely.
The attached two photos show the fuel tank, now devoid of pipe, and the broken end. Question is, what is left on the tank is presumably the stump of the nut, and a very short piece of pipe. Is it worth trying to extract the nut using a stud extractor? I have several of the type that are tapered reverse threads, that you screw in, and as they go in, they bite on the stud and being a reverse thread, they start to undo the stud.
Or do I just need a new fuel tank?

https://www.flickr.com/gp/116934447@N03/083W65

https://flic.kr/p/2kbMVQf

Cheers N

[philthehill]

This is what I would attempt before doing anything else.
Carefully drill out the broken pipe for the depth of the nut. Do not drill into the pipe flange. Use my picture (above) as a guide on how deep to drill. Then use the extractor in the remains of the nut and hopefully the remains of the nut will unscrew then you can pull the broken end of the pipe out of the tank.
Good luck

[ndevans]

Thanks. I'll give that a go. Would happen just after I've put the b----y thing back in wouldn't it!

[kevin s]

I hate the stud extractors, if they snap there is no way of removing them except spark erosion (probably not a good idea on a petrol tank!).

I usually keep going up in drill sizes until I get to the minor diameter of the thread then pick the remaining spiral of thread out.

[philthehill]

If you snap a stud extractor you will have used too much force.
I would try the stud extractor method as described above first. If that does not work try drilling out the nut in stages as described above.
The plain hole through the nut is 11/32" so start with the next size up and continue in size until you cut into the root of the thread. Then try and unpick the remains of the thread. If you have managed to unpick the first part of the thread you can use a 1/4 BSP parallel tap to remove the rest. Make sure that the tap starts into the original thread.

[ndevans]

Stud extractor did it's job. It was a lot easier than I thought, took under 30 min from entering the garage to leaving it! I plugged the end of the pipe with a small amount of sealing caulk to prevent any bits of metal getting into the tank. 3 min with a stud extractor mounted in a brace and it was out. New fuel line will be on order shortly.

IMG_20201130_200619404~2.jpg (1.29 MiB) Viewed 2411 times

Cheers N