[Healeys] Copper brake lines, was 100 BN2 almost done....

Oudesluys coudesluijs at chello.nl
Mon Sep 13 02:10:18 MDT 2010


  There seems to be some confusion about copper pipe used for brake lines.
Copper (100%) tube is and has been used for brake lines. This can be a 
dangerous practice as copper hardens when deformed making it brittle and 
prone to cracking. This deforming takes place continuously when braking, 
as the pipe will expand and contract a bit every time you brake.
If you use Cunifer, a copper alloy, there is no problem and this type of 
brake line has been around and used successfully for many years and 
several manufacturers use it as standard equipment.
Copper can be recognized by its reddish color and its softness, cunifer 
is pale yellowish/white and much tougher.
Copper coated steel brake lines (if they exist, I never came across 
them) are not a good idea because of electrolytic corrosion, the steel 
is sacrificed first and can fail after a fairly short time in wet and/or 
salty conditions. Zinc or cadmium plated lines are fine and used 
throughout the industry. The steel only corrodes if the zinc or cadmium 
has been sacrificed first and that only happens after many years.
Stainless steel can be used as well but also has some issues. It is hard 
to get in the right (aircraft) quality, it is hard to bend and it is 
difficult to make the required double flanges. A lot of people make 
single flanges, and although this works OK generally, it is illegal in 
many countries. These single flanges can be prone to fatigue cracking if 
not executed properly.
Kees Oudesluijs
NL

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