tube nut stuck

[stuffedpike20]

I am trying to replace the fuel pipe from tank to carb. I sprayed the tube nut pipe connector on the tank with plus gas and left it over night.
I have tried to remove it today but it is not moving.
I started with the correct ring spanner, which rounded it off. Then big pump pliers; then mole grips. All I am doing is destroying the tube nut more and more.
It is now practically round, and getting smaller each time I try to grip it. I don't really want to remove the tank from the pickup, but the mounting bar for the tank is in the way a bit.
Any suggestions please? I am worried I will damage the boss if I give it too much 'welly'.

Thanks, John.

[pgp001]

Dont be tempted to use a blowlamp on it

Phil

[stuffedpike20]

Very helpful (not)!

[les]

Difficult, could you attempt to tighten then loosen, a sort of waggling type of thing? Otherwise some decent stillsons which would bite in, and then take you chances.

[stuffedpike20]

I did try to tighten first. It will not move at all either way.
Will have to remove the tank to use stilsons on it.

[philthehill]

A bit late now but a pipe spanner is what you should use to undo pipes either brake or fuel.
They come in different sizes to suit your requirements. They are beefier than a normal spanner, have only six sides and have the slot to allow fitting around the union nut.
https://www.ebay.co.uk/itm/Brake-pipe-u ... %3A2334524

If you can get the union out I have what I believe to be a Minor tank fitting you can have for free.
Photo below of the fitting.

Pipe fitting 1.JPG (1.58 MiB) Viewed 1156 times

[stuffedpike20]

Would paraffin have been better than Plus Gas?

[Biggles1957]

Apparently a mixture of diesel fuel and acetone (nail polish remover) works very well to loosen fittings. I've never tried it myself but have heard its good stuff

[oliver90owner]

Tube nuts seem to be either male or female thread - if it is a female thread, cut/grind along the thread to remove any pressure on the thread. Even if brass, take care not to create any sparks when into steel unless any hole into the tank is securely sealed. Might be easier to ‘bite the bullet’ and remove the tank....

[stuffedpike20]

Thanks everyone; and for your kind offer Phil.
I am going out to have another go at it.
I have got an idea...........

[stuffedpike20]

The tube nut is now totally destroyed above the face of the boss.
I have taken the tank out and it is on its side with plus gas on.
Got about 2"of pipe sticking out but everything is still solid.
Any ideas?
If I fill the tank with water, can I safely drill the tube nut out?
Thanks, John.

[mogbob]

John
With the tank out and filled with water, I'd try an application of boiling water over the nut , rather than the
blow torch.It may need more than one application but I've loosened many a stuck nut / bearing with the method.
I easily cracked a paving slab with boiling water first time around , frightened the life out of me. If you put newspaper down it will stop water splashing over you.
Good luck Bob

[oliver90owner]

These days I often use left handed drills for extracting broken bolts/studs/etc if alternative methods fail or are inappropriate.

[stuffedpike20]

Thanks for the suggestions everyone.
I have had all the tools out today trying to remove the tube nut.
First I ground up a left handed drill bit, hoping the drill might grab and free the tube nut. No joy.
Then drill bits and a hand reamer to remove as much of the nut as possible, but leave the steel thread.
Ended up trying to pick out the copper thread with a darning needle! Only got the top couple of threads.
Then tried putting a couple of hacksaw grooves down an old tube nut to make a bit of a tap. Copper is softer than steel, so that did not work!
Now trying to identify the thread of the tube nut so that I can buy the correct tap to clean up what is left.

I filled the tank with water before using the drill bits, and noticed water coming out of a pin hole near the sender unit on top of the tank, so it is on borrowed time anyway. But there are no new tanks available at the moment.

All of this because I just wanted to fit a new fuel pipe from tank to fuel pump. What I was replacing was a copper pipe going the length of the car, but connecting to short metal stubs of pipe on the tank and fuel pump with flexible pipe and hose clips. I did not like the flexible pipe in the engine bay so close to the exhaust manifold.
So not really a case of 'if it aint broke, don't try to fix it', because I was trying to simplify things, and make a safety improvement.
If I had not started this work, I would still have been able to use my car; but I would not have known that there was a hole in the petrol tank.
Swings and roundabouts!