13 replies to this topic

[stuart bowes]

Can someone please confirm brake line flare types and sizes

 

**if there's a definitive post on this already can it be pinned maybe?

 

 

 

so far I have:

 

sizes

 

master cylinder, 1 x M10 (top, front brakes) + 1 x M12 (bottom, rear brakes)

 

then the bias valve which is all 4 x 3/8" (left side front, right side (offset) rear)  **or possibly metric ? just been watching a video on it arrgh**

 

everything else is just 3/8"  ?? including the T piece at the rear subframe, those ones went in all the way using fingers, I think they're a good fit 

 

also I need to work out what happens around the front subframe, I'm sure I've got the bits somewhere (ill look at the diagrams)

 

 

flare types

 

I've read a post saying bubble type flare everywhere except where connecting to flexi hoses, which need double flares? is that right 

 

I've been doing double flares everywhere but I've not done loads yet I can easily change them

Edited by stuart bowes, Yesterday, 02:20 PM.

[mbolt998]

Below was the discussion I had about it.

 

What worked for me, in the end, with copper pipes, was just to do an SAE double flare on everything (I thought I'd done them wrong in that first post, but they are actually fine).

 

Many people will tell you this is completely wrong, and also that you should never use copper pipes. So I'm just saying it worked for me.

 

The reason I will continue to always do both operations of the flaring tool is that by folding the end of the pipe back in you're always squishing together something that is double thickness and therefore nice and strong. Copper is deformable enough that you get a good seal this way, even when using an inline connector, one side of which you would think ought to be male. If anything's leaking you will know about it at once. If the ends of your pipes are thin and crack later that is more dangerous IMO.

 

The yellow tag MC is metric, as is the pressure limiter from about 1979 on that is in the engine bay rather than on the rear subframe (that's the kind I have). The wheel cylinders are all imperial (I have drums all round, don't now about disks). Just make sure you have the right one!

 

My T-pieces and things were imperial but you never know. Somebody might have changed them. An imperial union will go in a metric hole but wobble very slightly so just check for that. You might think it's gone in all right at first.

 

https://www.theminif...uble/?p=3731051

Edited by mbolt998, Yesterday, 03:28 PM.

[stuart bowes]

thanks I think that covers it all then, much appreciated

 

now I see that picture in your thread I realise I did already read that a while back

 

still think this could be a nice simple clear sticky post instead of having to read through people arguing about it lol

[weef]

I read on this forum regularly about " double flare everything and it will be fine".............

Never double flare if it is not a concave union you are screwing into, to form the double flare you have to single flare the tube end first so why double flare.

If you are making up brake tubing and cannot tell the difference  then I suggest you do not play with this safety system.

Brake flaring tool manufacturers don't make their products with both dies because they can, they are there for the good reason.

My take on this is if you cannot tell what tube flare is needed then seek professional help.

[mbolt998]

thanks I think that covers it all then, much appreciated

 

now I see that picture in your thread I realise I did already read that a while back

 

still think this could be a nice simple clear sticky post instead of having to read through people arguing about it lol

I've put a few thousand miles on those brake lines I did with no issues so I consider it good enough for me. It's such a confusing subject though!

[Spider]

If you are unsure if a Port is 3/8" UNF or M10 x 1.0, as they are very close and a 3/8" UNF Tube Nut will screw in to an M10 x 1.0 Port, but is potentially dangerous, one way to work out what you have is if you have an old tube nut that you know came from it, try screwing it in to a wheel nut. If it goes in, it's most likely 3/8" UNF and if it doesn't, then M10 x 1.0. Another similar way is to obtain an M10 x 1.0 screw and use that for testing.

 

The Single Circuit Master Cylinders are 3/8" UNF.

 

The CMC 159 and GMC160 Tandem Masters are 3/8" UNF on both ports.

The GMC 167 (sometimes called a Green Tag) Master Cylinder is M10 x 1.0 on both ports. There is an earlier version of these (black tag) that were 3/8" UNF.

The GMC 227 (yellow tag) is M10 x 1.0 and M12.x 1.0

 

The GMC90376 I need to check and confirm.

The FAM7821 and the FAM4670 are M10 x 1.0

All other Brake Valves are 3/8" UNF

All Brass Tee's and other Unions are 3/8" UNF.

All Brake Hoses are 3/8" UNF

 

Most Joiners are 3/8" UNF, however, there were some M10 x 1.0 used too. BE AWARE most of these take a Invert Flare (refer to the link below on Flare Types for a correct description of these), though some use Doubles. You will need to confirm the Thread and Flare type needed here.

All Wheel Cylinders are 3/8" UNF.

For completeness, the Factory twin pot Brake Calipers are 3/8" UNF, though these have the hoses screwed directly in to them, with a copper sealing washer.

 

Flare types;-

https://www.theminif...ngs-and-flairs/

[Spider]

Many people will tell you this is completely wrong, and also that you should never use copper pipes. So I'm just saying it worked for me.

 

Many early cars (not Minis !) going back to the very earliest days of Hydraulic Brakes used Copper Lines, though they have become illegal in most countries as the Copper supposedly will work harden from road vibration and eventually crack. Also, under the SAE (and likely other standards), hardline Brake Tube needs to be double walled, often referred to as Bundy Tube.

Personally, I'm not sure I agree here in regards to the copper lines cracking, but given the choices available these days and the cost of copper, it's probably not the best way forward.

[weef]

I can only stress again never use the wrong flare profile for the job at hand.

The tolerances involved in the manufacture of quality flaring punch and die equipment is such that, when used correctly, there is no risk that the integrity of the produced flare is compromised, no matter the material composition of the tubing used.

As there are only two possible options to the flare profile it is not too difficult to decide which profile is required, and as I said before if you cannot tell ,stop and ask someone who can explain the difference.

I cannot comment to the flares produced by inferior quality tooling.

[Bobbins]

And if you’re putting the time in to construct your own brake lines, buy a proper tube straightener to do a professional job. The fastest way to make a rebuild look crap is to use hand straightened brake lines.

Edited by Bobbins, Yesterday, 09:01 PM.

[stuart bowes]

Its OK I'm aware of the right flare types now, thanks for advice, I have the tool to do both types required

Spider thanks for the useful info that makes sure I definitely have all the info I needed. My simple mistake was forgetting to check thread sizes really and then just in passing I read someone's post who pointed out two different flare types so I'm now making sure I'm doing the right ones

I appreciate safety is a concern this is why I'm checking. But also, everyone has to learn the first time at some point and obviously extensive testing will be done

[Spider]

Its OK I'm aware of the right flare types now, thanks for advice, I have the tool to do both types required

 

I apologize if I seemed a bit bombastic about the flare types. I am in no doubt you have the right tool and well capable of making them properly, I just get a bit 'narky' over the terminology used in regards to flares, they can be inter-changed so easily and can lead to confusion and the wrong types being used. In my books, there's only Double Flares and Invert Flares.

[mbolt998]

 

Its OK I'm aware of the right flare types now, thanks for advice, I have the tool to do both types required

 

I apologize if I seemed a bit bombastic about the flare types. I am in no doubt you have the right tool and well capable of making them properly, I just get a bit 'narky' over the terminology used in regards to flares, they can be inter-changed so easily and can lead to confusion and the wrong types being used. In my books, there's only Double Flares and Invert Flares.

 

So now I'm really confused again :) It looks from that post about the flare types that if I do the first operation with my tool, that's actually a "double flare". If it then turn the tool around and do the second operation, I have an "inverted" flare. Is this right?

[Bobbins]

From Locost Builders.

[Spider]

So now I'm really confused again :) It looks from that post about the flare types that if I do the first operation with my tool, that's actually a "double flare". If it then turn the tool around and do the second operation, I have an "inverted" flare. Is this right?

 

Correct.

Those are the Terms used by the SAE and the only ones I use.

I have seen in particular the 'double flare' term interchanged with an invert flare may times - as per Bobbin's post above (and note that is not from the standards) - and as you can see, from the SAE and BMC Standards, they are very different things.

Most tooling works as you have said, first operation is to make a Double Flare then if it's needed, from the Double Flare, form an Invert Flare. I have a few tools for making them, they all work this way.