21 replies to this topic

[Spider]

Did minis come from the factory with copper hoses ?

 

Copper Pipes? No.

[tiger99]

Never! They were double layer steel, dip brazed aka Bundy pipe like almost every other car. It is what has to be used in many places (USA, most of the EU, Australia etc), copper being usually illegal, except in the UK, because the idiots at DVSA don't understand the problem.

Copper has not been used on new cars since the late 1940s and hopefully never will be. The mainstream manufacturers know that the stream of law suits that would follow would ruin them.

[tiger99]

Oh, and certain grades of stainless might be quite useful, but you unfortunately would need an immensely strong flaring tool. Kunifer is the best all round material.

[998kid]

Ok thanks for the help on the not copper pipe size and materials

Are the braided lines also 4.74mm?
As I can get all the fittings for next to nothing so may just order a meter or two of the braided lines and make my own

[Spider]

Are the braided lines also 4.74mm?
As I can get all the fittings for next to nothing so may just order a meter or two of the braided lines and make my own

 

I don't think you can legally use Brake Hoses that you make yourself. Brake Lines ('hard' pipes) you can.

 

The 'Hard' Brake lines, the like of which for example, run from your Master Cylinder to a distribution Tee or Pressure Valve etc are a Hard Line. The flexible Hoses that are normally rubber that run from the Subframe to the Brake Calliper and Trailing Arms are Brake Hoses. These are available as a braided type but, as I mentioned, i doubt if you can legally use ones in this type, that you've made yourself. Certainly here (In Aust), you can't.

 

The hard Brake Lines are 3/16" (OD). I would warn against asking for them by a metric number as there is 4.5 and 5.0 mm sizes available, neither of which work correctly with the fittings used in a Mini and seldom to they flare properly in the tooling for these fittings.

 

The nominal size for the (Flexible) Hose used in the Hose assemblies is typically 1/8" or 3.0 mm, however that doesn't matter too much as long as the fittings on the end match up with the Hard Line fittings used. For what these Hoses cost, either as an off the shelf part or as a custom made hose, it's simply not worth messing with.

 

Hard Lines are a different matter.

 

<EDIT: frequently the Pressure in the brake Hydraulic System under normal driving conditions will be in the 700 PSI range, and can easily go as high as 1000 PSI, peaking at around 1200 PSI under emergency conditions. Hydraulic Brake Parts have a rated Operating Pressure of 3000 PSI (though most is 4000) and a Burst Pressure of 12000 PSI. Special (and usually Certified) equipment is needed to crimp fittings to Flexible Hose fittings to the hose to guarantee these ratings. >

Edited by Moke Spider, 05 May 2017 - 01:16 AM.

[nicklouse]

flexy hoses are measure differently "dash" sizes.

 

As to the legality of making your own there is currently no checks made (paper work) to prove either way.

[tiger99]

Yes, that is so, and only the two smaller dash sizes are rated for brake system pressure. The smaller one is used mainly on racing cars. Larger sizes are strictly for much lower pressure fuel, oil and water etc.

 

Almost all threads on the Mini brake system are 3/8" UNF, but beware of the master cylinders with 10mm and 12mm to avoid crossing over the ports. Forcing a 10mm into 3/8 or vice versa is downright dangerous, and common sense dictates that any fittings should be loosely screwed together by hand before installation to ensure that the thread fits snugly and goes all the way in without force.

 

You will have both male and female tube nuts in the system, and pipes with single flare or double flare. The single flare is male as far as the seating is concerned and goes into a fitting which is conical like a countersink at the bottom of its bore. The double flare is effectively female at its interface and goes on the pointy end of a hose, with a female tube nut. But there are a few silly cases, possibly not on Minis, where a single flare is used with a female tube nut, or a double flare with a male tube nut. It is easy to tell visually what you have and need. If in doubt, feel gently down the port with a soft, clean stick to see which way the taper on the seating goes.

 

You also have one banjo fitting on a Mini at the right hand front hose on the subframe. If you buy a set of hoses, one will be machined flat on its end face for the copper washer to make a seal, and will not have an internal cone to seal a single flare, while the other will not be machined flat and will have a conical seating. They could have been made identical. Don't ask why not, I don't know. This has caused questions to be asked and answered here before, because people had leaks, not realising that the hoses were different.

 

But you don't need to be concerned with bore size. The supplier takes care of that. You just need length and end fittings. You typically have a female end which takes a male tube nut and single flared pipe, a male end which is pointy and takes a double flare and female tube nut, or a flat end with male thread that requires a copper washer to seal against a flat surface. Then there are variants of thread length, fixings etc. Check the web sites of the kit car suppliers and such like, or Goodridge themselves. Mostly, they know all about the correct parts to supply for a Mini. I think I got my last set from Demon Tweaks as they were the cheapest for the same Goodridge items.

 

Moke Spider, Australia is well ahead of the UK on some aspects of safety. As well as not allowing copper, you can't make up hoses at home. Rightly so, if swaging is involved. However in the UK we are allowed to make up Goodgrige type hoses, which use a screwed compression nut, acting on the stainless steel braid, the PTFE inner going over a barbed sleeve. I personally will not be making any at home, and don't recommend that anyone else does either, as it is best left to the experts who will pressure test them after assembly.

 

After fitting new hydraulics I always do an informal pressure test by putting all my weight on the pedal, both feet, and holding it for a minute or so. Sat properly in the seat, you can actually manage almost double your weight. A strong person will probably get to 2000 to 3000 psi. You don't need the engine running for the test if you have a servo, because it will run out of puff, or rather, suck, before you do.

 

Edit: In the UK you just need to order 3/16" brake pipe. It may be labelled as 4.75mm. The other sizes are very uncommon here except maybe on larger vehicles.

Edited by tiger99, 05 May 2017 - 10:23 AM.