copper brake pipes

[Leo Jormanainen <lexa@xxxxxxxxxxxxxxx>]

Hi,

It doesn't need any calculations, copper tubing in any brake system
is dangerous and illegal here in Canada.

Leo
QCI





At 09:52 AM 31/05/2002 -0500, you wrote:
>At 02:52 AM 5/31/2002 -0400, you wrote:
>>I
>>have never had a copper pipe rupture and I have had plenty. Is this risk
>>particular to heavy U.S. cars? If so I will ensure that the replacement pipes
>>are steel.
>>
>>Tony V.
>
>Tony, I am not sure if Imperials have particularly higher brake line 
>pressures than your usual car in Britain.  I think that the higher brake 
>forces are achieved by using larger calipers, brake cylinders, and master 
>cylinders rather than higher pressure.  Also, drum equipped cars like 
>yours have inherently lower line pressures.  I would guess the shop manual 
>will help with the question of how high pressure is built up inside the 
>brake system.  If I recall, on a 68 (disk brakes) the pressure can reach 
>1200 psi.  Now, does copper have sufficient strength?  Well, some of these 
>pipes (flexible hoses) are actually rubber, so if rubber can take the 
>pressure, then copper should too.  Of course, the rubber hoses are of much 
>higher thickness than the steel lines to limit expansion.  Then again, we 
>do not know how thick wall the copper lines used in the UK are.  They 
>might be of thicker wall than the steel lines used in the US.
>
>Calculating the stresses in a pipe based on pressure, pipe ID and wall 
>thickness is not difficult.  If you can provide me this information, and 
>the copper alloy used (I can hopefully find info on the strength of the 
>material) I may be able to do some rough calculations and tell you if the 
>material selection is improper.  My guess though is that if they use it in 
>a large scale over there, it should be fine.  Here in the US, often the 
>"safety" regulations go beyond sense...
>D^2
>
>
>