49 replies to this topic

[gav]

It could well be fine but given the choice and the fact it's only 10 seconds extra work to do the 2nd op I would make them as per the world's leading classic car brake pipe manufacturer ;) 

 

From Automec themselves:

 

When using copper or copper nickel pipe it is essential to use a double flare. This is different to the bubble type used with old steel pipe. Essentially the double flare is specifically designed for use with these materials to ensure the safest possible connection. As we have only used exclusively copper and copper nickel pipe on all of our brake pipe sets for over 45 years of manufacture and distribution around the world, each and every one of our sets uses this double (OP1 and OP2) flare. In simple terms the rule is as follows:

Steel Pipe - Single or 'bubble' flare

Copper/ Copper Nickel Pipe - Double flare

[Ethel]

This terminology ain't half confusing...

 

If single flare means pushing a male cone directly in to the end of the pipe to make it wider, then that isn't suitable.

 

If it means pushing the end of the pipe with a former that stops the open end expanding and causes it to "bubble" instead to form a shape that will seal if pressed in to a female cone shape, that's good.

 

A double flare then is understandable as performing a 2nd operation on that (2nd) definition of a single flare that inverts the end in to a female cone shape - as the tube wall is double thickness and/or it took two flaring operations to make it.

 

Open to suggestions, for terms to eliminate any confusion...

 

single male, double female?

 

Should we really be differentiating between DIN & SAE instead, metric or imperial?

[KTS]

 

Should we really be differentiating between DIN & SAE instead, metric or imperial?

 

..would any of that help answer the OP's original question with regard to what is appropriate for hydraulic fittings on a mini ?

[Ethel]

I think so - he mentioned single flares and there seems to be differences of opinion in what that means.

[KTS]

apologies; it was a poorly worded response, and agree that clarity is what is needed

 

as far as i'm aware all the hydraulic fittings you'd find on a standard mini are SAE, and the tool the OP is using is a 3/16" SAE tool, so he should have no issues forming the flares the fittings are designed for with the tool he has.  

[mbolt998]

It could well be fine but given the choice and the fact it's only 10 seconds extra work to do the 2nd op I would make them as per the world's leading classic car brake pipe manufacturer ;) 

 

From Automec themselves:

 

When using copper or copper nickel pipe it is essential to use a double flare. This is different to the bubble type used with old steel pipe. Essentially the double flare is specifically designed for use with these materials to ensure the safest possible connection. As we have only used exclusively copper and copper nickel pipe on all of our brake pipe sets for over 45 years of manufacture and distribution around the world, each and every one of our sets uses this double (OP1 and OP2) flare. In simple terms the rule is as follows:

Steel Pipe - Single or 'bubble' flare

Copper/ Copper Nickel Pipe - Double flare

Thanks. This is definitely a vote for SAE double flares on everything, regardless of "bowl" or "volcano". This is what I have so far (but I won't know if it's any good until I've done all the lines and start building pressure).

[mbolt998]

I think so - he mentioned single flares and there seems so be differences of opinion in what that means.

Yes it would be helpful for exactly this reason.

[mbolt998]

apologies; it was a poorly worded response, and agree that clarity is what is needed

 

as far as i'm aware all the hydraulic fittings you'd find on a standard mini are SAE, and the tool the OP is using is a 3/16" SAE tool, so he should have no issues forming the flares the fittings are designed for with the tool he has.  

Yes and I think I should be doing the double flare on everything.

[mbolt998]

This terminology ain't half confusing...

 

If single flare means pushing a male cone directly in to the end of the pipe to make it wider, then that isn't suitable.

 

If it means pushing the end of the pipe with a former that stops the open end expanding and causes it to "bubble" instead to form a shape that will seal if pressed in to a female cone shape, that's good.

 

A double flare then is understandable as performing a 2nd operation on that (2nd) definition of a single flare that inverts the end in to a female cone shape - as the tube wall is double thickness and/or it took two flaring operations to make it.

 

Open to suggestions, for terms to eliminate any confusion...

 

single male, double female?

 

Should we really be differentiating between DIN & SAE instead, metric or imperial?

DIN flares are sort of supposed to be metric. But the steel lines coming off my '79 Mini have what I'm pretty sure are DIN bubble flares even though the nuts are obviously imperial threads.

[weef]

DIN flares are used in conjunction with DIN profiled tube nuts. These tube nuts have a square faced end, not the concave profile of the SAE. Correspondingly the back face of the flare is square, not the convex profile of the SAE.

It is the die part of the brake flaring tool that gives this profile, the punches, OP1 and OP2, are still the same. 

Do not mix DIN flares with SAE tube nuts and vice versa.

On the Classic Mini, as far as I am aware, it was always the SAE profile that was used, but on following this post with all the comments taken into account the pipes may have been replaced with anything. 

[mbolt998]

DIN flares are used in conjunction with DIN profiled tube nuts. These tube nuts have a square faced end, not the concave profile of the SAE. Correspondingly the back face of the flare is square, not the convex profile of the SAE.

It is the die part of the brake flaring tool that gives this profile, the punches, OP1 and OP2, are still the same. 

Do not mix DIN flares with SAE tube nuts and vice versa.

On the Classic Mini, as far as I am aware, it was always the SAE profile that was used, but on following this post with all the comments taken into account the pipes may have been replaced with anything. 

Yes this is an excellent point about the nuts. The new nuts I have that are going on have the concave end (and my tool does SAE flares so that's good). The ones coming off however are flat nuts and DIN flares (even though the nuts are imperial threaded), as you can see on the right of this image.

 

As far as I know those are the original lines on this 1979 car. I have owned it since 1990 and I doubt they were replaced in the first 11y of its life.

 

[Ethel]

That does look an awful lot like a metric union, where's it from? There can be a mix of Metric & UNF unions on Minis from the late 70's on. The GMC 227 Master cylinder & FAM7821 valve are.

 

3/8unf will go in m10, but it's loose.

 

9.525mm x 24tpi vs 10mm x 25.4tpi

[mbolt998]

That does look an awful lot like a metric union, where's it from? There can be a mix of Metric & UNF unions on Minis from the late 70's on. The GMC 227 Master cylinder & FAM7821 valve are.

 

3/8unf will go in m10, but it's loose.

 

9.525mm x 24tpi vs 10mm x 25.4tpi

 

It's off my 1979 Longbridge-built Mini 1000. Pretty sure original (as I have owned it since 1990). Metric in the sense of DIN, but the flats on the nut are 7/16 (which is not close to any metric size) and my replacement nuts go into the same threads (and feel right, not loose or anything). So it's an imperial nut, but with a flat end designed to be used with a DIN flare.

 

I'll have a closer look at some of the others but I think they're all like this.

[Ethel]

It should have a Fam7821 brake regulator. The wheel cylinders & hoses will be imperial. I wouldn't make assumptions about anything else.

[Mr Piggy]

That old tube nut does look like a metric one. I've been a mechanic for 40 odd years and don't recall seeing a mix of a square back metric type flare with an imperial threaded nut. You need to measure the thread diameter or buy an m10 x 1mm pitch tube nut. If you can screw that in then it's an m10. There is a serious risk of it popping a thread under pressure and an instant brake failure if you put a 3/8" tube nut into a 10 x 1 thread. As regards spanner sizes, a 7/16 af will happily fit on a 11mmhex nut.
We never used copper pipe as, has been said, if it's not securely clipped up it can work harden and fail. I have seen this. Cupro nickel was our favoured type. As for flares, we always refered to them as op1 and op2. If you want a concave flare to match the seating then it's op1 followed by op2. NEVER JUST OP2! I've also seen this and it was weeping fluid. I don't agree with the idea of doing both op's on everything but maybe it just makes it "idiot proof".