Copper Brake Lines?

[SilentUnicorn]

how do you folks feel about compression fittings? I was recently told a friend had a truck that wouldnt pass a state inspection because of them. seems kind funny to me. i have used them in the past and never had any problems with them.

mark

 

[Guest]

I installed the copper/nickle brake lines from the Moss-suppled kit and have had no problems with them. Very easy to bend and install, never had a leak problem and the kit is well designed with all pipes made up to perfect lengths.
I would highly recommend them. You might check out other vendors for the same product (forgot the brand name, surely someone on the forum remembers) as prices tend to vary. (Is that a PC way of saying Moss is high?)

Bill

 

[Guest]

I use swagelok fittings only, mainly because this is what I use in my lab and I can get them for nothing, plus I think they are the best type (two piece ferrul). I've put a few hundred psi of pressure through them in gas service without problem, using everything from nitrogen and helium to highly poisonous stuff like chlorine, hydrogen bromide, and phosphene. However, I would not recommend them for use in a hydraulic setting, such as brakes or clutch. Compression fittings are designed more for steady state pressure, not the repeated no pressure/high pressure stresses that would be involved in a cars hydraulics. Plus I think the max pressure involved in a brake system is over the max pressure of most compression fittings. I do use them on my fuel line fittings though, thats a good application, low steady pressure.

I do believe the are illegal in most states for brake systems. I've never been tagged for having them on my fuel lines though, since my car never goes through inspection.

 

[71tr]

Automec out of the UK is the company which makes the pre-cut copper-nickel brake lines. Moss #588-188 or Automec #GL6230 for a TR6/TR250. Wow, Moss is asking $147 for the set. Bought them on ebay for about $89 from Triumphs Only I think.

 

[JamesWilson]

[ QUOTE ]
Please take no offense, I'm not trying to contridict anyone. I truly believe that those of you in the UK have referred to them as just "copper" for so long that it's not thought of as an alloy anymore. But I believe if you do some research you will find that they in fact are an alloy. .... If you find some proof of them being 100% pure copper, then post it (or a link to it) here and I will gladly admit my error.

[/ QUOTE ]

https://secure.visav.co.uk/avshop/products.asp?getcats=true&cat=29&scat=128

Is a link to Europa Specialist Spares with both "Copper" and the Kunifer copper-alloy lines listed on the same page. Merlin Motorsport refer to "pure copper" lines too:

https://www.merlinmotorsport.co.uk/p_brake_brake_parts.html

So two different sources, one explicitly describing them as pure, and the other offering both copper and alloy on the same page.

Is that proof enough? No offense taken. There's no bee under my "bonnet" about it.... /ubbthreads/images/graemlins/smile.gif

 

[Banjo]

Excellent retort James. Well put.
I admit my error.
I also admit my suprise. I really dident think they would be marketing the pure copper, especially in a motorsports application. They obviously know somthing contrary to everything I've heard and read, not that that'a hard to believe. (Guess I'll have to hear and read a little harder).
As a side note: If you are buying pure copper lines in the U.S. you are likley going to find them at a hardware store. These are ABSOLUTELY NOT rated for automotive use. If you must get the copper lines, source them from one of the places like James has showed us.
I will not again argue the use of pure copper line. Only Hardware store copper line.
As for S.U.s question on compression fittings. I do know about that.
Compression fittings are not rated for the kinds of pressures that modern power assisted brakes can develope. and Being a licenced N.Y. state inspector I can say that in N.Y. a compression fitting on a brake line is an automatic fail.
You could probably get away with one on an older car without power assist, but it's still not a good idea, and it will still fail inspection.
P.S. also if an inspector finds copper brake lines it's an automatic fail. The customer would need to supply proof of them being rated for automotive use.
Swagelok fittings on the other hand are overly suited for automotive hydraulics. They are rated for pressures much higher than even modern systems can produce. They are actually better than the factory flare type connection. They aren't commonly seen because of thier excessive cost as compared to flare type fittings.

 

[JamesWilson]

One of the other posters has mentioned using "Automec" lines, who are probably the best known brand name for these. They describe theirs as:

https://www.automec.co.uk/pipe_coils.html

"Copper and Copper Nickel Coils - 25ft(7.62mtr)

Top quality thick-walled (0.9mm 20swg) Copper and Copper Nickel coils, conforming to BS 2871 Part 3, C106/CN102. Batch tested for tensile strength, burst pressure and cleanliness to BLS.30.JC.101. Each coil marked for traceability. ..."

So it does seem that these are rather better than off-the-shelf copper tubing, though I must confess to never having looked before at the requirements for BS (er, British Standard, that is). For 3/16 tube (part 2 of the standard, rather than part 3) the working pressure seems to be 2589 PSI.

I did track down some Bundy tubing from an industrial supplies vendor but the automotive vendors here just look puzzled when asked about it. I've bought enough of it to re-do my car.

For 3/16 Bundy tubing the burst pressure rating is 16500 PSI. The source unfortunately doesn't list the pressures for the copper alloy. Though comparing copper working to Bundy burst pressures would be looking at apples and oranges it does seem quite a difference, besides the work-hardening and flexing issues.

Using pure copper seems a non-issue for I've never heard it mentioned and the use of the Kunifer copper-nickel alloy seems the popular upgrade... the main Healey (and the biggest one for Triumph- Rimmer Bros) parts vendors only seem to supply the copper as standard.

 

[Guest]

Hey Banjo, maybe I've got my info wrong, but I thought Swagelok's standard tube fittings are considered a compression type fitting. The thing that makes swagelok unique, and thus able to handle higher pressure limits, is the two piece ferrul instead of just one. Unlike a standard compression fitting and ferrul, once you "swage" the swagelok fitting to the tube, it's on there pretty permanently. You can't take it apart and remove the ferrul from the tube (at least not easily), and this gives you the ability to disconnect the tube and reassemble it while maintaining the same level of pressure resistance as when it was first assembled. There are other types of Swagelok fittings that are not compression type, like their VCR metal gasket face seal fittings, but these wouldn't be suited for a brake system (and they are insanely expensive to). I've also used two piece ferrul fittings that were not made by Swagelok, I believe Gyrolok is their main competitor in this area, and their fittings are very similar. After some more thought I'll take back what I said about not using them in areas with rapidly changing pressures. In the past we've used them in applications where we've gone from hundreds of PSI to 0 and back rapidly while purging manifolds and systems and have had no problems. I've been digging for some specification info on the pressure ratings of Swageloks fittings and the pressures typically encountered in an auto hydraulic system. My quick search didn't turn up much, but if I remember correctly a typical auto master cylinder is putting out pressures on level of hundreds of PSI. I don't remember ever using Swagelok fittings on anything over a few hundred PSI in gas service. Whenever we had pressures higher than a few hundred PSI we would use a stepdown regulator, which was usually fitted with standard CGA connectors and NPT pipe thread fittings. I don't think I'd be comfortable using any compression fittings, including swagelok, on a brake system, why risk it. Admittedly they are easy to use, especially the no need for flaring part, but I don't think I'd be willing to risk my life on it.