5 replies to this topic

[DripStand]

Hi going to fit a new front to rear copper brake line. Original one fits behind the rear subframe . Without removing subby.

Can I feed the new pipe around and bend it back on itself leaving a 180 turn or turning around at 2 90 degree bends to fit into 3 way splitter in sub frame (hope that makes sense!).

My main question is will there be any mot considerations as that will leave quite a bit of pipe hanging freely away from any clips? What have people done in the past?

Thanks

[tiger99]

There are two considerations here. Firstly, DO NOT USE COPPER! There is no such thing as copper brake pipe, in terms of things like BS specifications, and the stuff supplied as such isn't fit for purpose due to poor fatigue properties. It may be in accordance with a BS spec for "Copper Pipe for General Use", but that specification does not mention brake systems at all and does not specify an adequate number of fatigue cycles. Copper-nickel 90/10, often known by a brand name, Cunifer or Kunifer, is made to ASTM B466, ISO 4038, SAEJ1047 and various other standards, and is fit for purpose, having an adequate fatigue rating in terms of pressure cycles. Copper should never be sold as brake pipe, but there again neither should dodgy wheel bearings, which currently flood the market due to greed and ignorance on the part of the suppliers.

 

Secondly, it should be fitted as per original. The subframe moves significantly on its mounts, especially if you have the later, softer mounts, and taking the pipe via the original route provides a nice neat loop where flexing may occur harmlessly, if you use steel or copper-nickel. Copper would tend to fracture. The MOT tester will not necessarily be aware of the serious problem with copper pipe (which can easily be distinguished from copper-nickel) but he would likely take exception to a big loop passing under the subframe, which as you have said would be unsupported. The original pipe was routed the way it was for very good reasons, and you will note that it .passes sideways over the bottom edge of the heelboard to avoid an excessively tight bend. One of my Minis, probably the earliest,  had the pipe coiled by 1.5 turns, maybe 3 to 4 inches diameter, instead of just a plain doubling back loop. to provide even more flexibility. It appeared to have left the factory like that.

[DripStand]

Thankyou for that very detailed reply. I believe the front to rear pipe I have is a "kuffner " pipe as bought from mini spares however I have bought and am awaiting delivery of a set of "100% copper" brake pipes to fit the rear sub and on radius arms so will need to reevaluate what I'm going to do. You said it is easy to disguinguish between copper and 90/10% mix . How is that to my relatively untrained eye.

Thanks again

[tiger99]

Copper is red and shiny when new, or recently polished, and is noticeably soft when you come to bend it. Copper-nickel is red but with a grey tinge, which does not polish away, and is much tougher when you come to bend it. Some bleat about it being impossible to work with, which is pure nonsense, as it is more malleable than the original steel bundy pipe.

[gazza82]

I think you just need better tools to work with the Kunifer and not flea-bay specials ..

[tiger99]

Just a good flaring tool, but you need a good one anyway, regardless of material. I have never needed a bending tool, but a cheap one should be ok. I find working with the proper material is quite pleasant.