Flare nut detail for 1/4'' pipe - urgently needed.

[Pinger]

Replacing - or attempting to replace - rear section of 1/4'' brake pipe on my 1999 C2500 Suburban 5.7l with JD7 system. Intended re-using flare nuts (on home flared copper/nickel pipe) but one of them is going to end up destroyed in the removal process so need to source replacements. Inevitably that means in the UK - Rock Auto don't list - and to save time but I don't have the size at hand. Any info that lets me identify what I'm looking for in the UK urgently required and greatly appreciated!
TIA.

 

[RichLo]

If you have the tube flaring tool, I would use a flare nut butt join instead of those compression fittings. Better seal and easier to remove down the road. Those compressions are intended at a 1-time use emergency fix.

 

[Pinger]

Maybe my terminology is off. Here is the type of nut I need.

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One end of the pipe I'm replacing joins to the rear flexible hose, the other end into a connector attached to the rest of the steel pipe that runs forwards. All I know of the dimensions so far is that the hex is 14mm across the flats. Once I know the thread size and any other detail (eg a shoulder) I can probably source them here in the UK.

 

[xXxPARAGONxXx]

Do you see the part in this photo? If so, what #?

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[0xDEADBEEF]

My best guess ...

if SAE 9/16-18
if metric 14mm x 1.5

 

[Schurkey]

My guess is #5.

He's creating #6 from a roll of tubing.

 

[Pinger]

Do you see the part in this photo? If so, what #?

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5.
As shown in two locations.

 

[Pinger]

My best guess ...

if SAE 9/16-18
if metric 14mm x 1.5

I haven't removed anything from the truck yet - daily driver so need all the parts before I start. I do have an old flexible hose and the thread that accepts the nuts I'm after is 10.5mm ID ie, across the peaks of the thread. The corresponding male thread is larger by twice the thread depth. Does that help at all?

 

[xXxPARAGONxXx]

5.
As shown in two locations.

Without your VIN, it might not be correct, but it should be the following:

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So, should be 1/2-20 thread brake nut.

 

[Pinger]

Without your VIN, it might not be correct, but it should be the following:

You must be registered for see images attach

You must be registered for see images attach

So, should be 1/2-20 thread brake nut.

Does the '20' refer to 20TPI?