I read through some of the links provided. Thanks for sharing this info. I'm glad there was at least something written to support my post.

90Cu-10Ni is expensive. This alloy is also closer to some of the naval alloys used for corrosion resistance, so copper contamination of the brake fluid may actually decrease! The copper.org site has good technical information, but it's primary function is to promote use of their product (copper) in industry, thus the article has a bit of slant in that direction.

Given the longevity of modern, complex automobiles (since people can't afford to throw cars away after 7 years anymore), we're beginning to see some parts of cars now being made of premium materials. Some examples are stainless steel (or even titanium) exhaust components, gold-plated bulkhead connectors, coated pistons, LED brake lights, and 100% production magnafluxed crankshafts.... technologies previously reserved for the aircraft industry. And these are only the technologies I'm familiar with.

My guess the reason these technologies weren't used before - even though they were cost effective when considering total vehicle ownership and maintenance - is that manufacturers wanted to keep the sticker price low on these cars. Stainless steel for exhaust was justified long time ago, but wasn't incorporated until recently. Back then, the average consumer didn't really care if the car had stainless exhaust. They simply went down the street to another dealer if they could save $70 on the sticker price of a comparable new car. The push for premium materials may be to keep NHTSA at bay.

I notice the 90Cu-10Ni brake lines are now being used only in premium automobiles (Volvo, Lotus, Aston Martin, Porsche, Audi, all military vehicles, fire tenders, JCB's and other heavy vehicles), though I'm bummed that MB hasn't considered it for their vehicles. We can probably expect wider acceptance of this new brake line material.

BTW, it's not work-hardening properties of brake tubing that are important - it's the fatigue resistance and burst pressure. Work-hardening properties are more important for the forge or roll mill industries.

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95 E320 Cabriolet, 159K

[QUOTE=Kestas
BTW, it's not work-hardening properties of brake tubing that are important - it's the fatigue resistance and burst pressure. Work-hardening properties are more important for the forge or roll mill industries.[/QUOTE]

Common copper tubing has never been acceptable for transportation equipment. My understanding is that it's due to the vibration environment and the poor work hardending properties of copper that quickly make it brittle when used in a vibration environment, but I suppose it could also be a fatigue issue, and plain copper tubing certainly has lower burst pressure than equal wall thickness mild steel tubing.

Duke

What is the composition of Castrol GT-LMA brake fluid? It's the only brake fluid I ever use, and my uncle recommends it for any and all cars (specifically the Dino... Apparently it's not harsh on seals and such). I don't have a bottle handy to perform the test, but my car is going to need a brake system flush sometime soon. I'd like to know out of curiosity if it's silicone or glycol.

Odd...........I have DOT 5 silcone fluid in my motorcycle brakes...and that is purple like welches grape juice. Never saw the green stuff before.

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Anthrax, check the bottle.

DOT 3, DOT 4, and DOT 5.1 are glycol based. They are each compatible with one another and can be mixed.

DOT 5 is silicone based and not commonly used. It is not compatible with the above three. I'm glad to hear it's colored differently.

One quick check to see what fluid is in your system is to take some out and see if it mixes with water. Glycol will mix in water, silicone won't.

There is no dino brake fluid. They are all synthetic.

Harley Davidson is the only vehicle manufacturer I know of that specifies DOT 5 for their motorcycles. I believe the reason is so the fluid won't ruin the finish should it get on the painted surfaces during service. HD is very anal about the finish and appearance of their product.

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95 E320 Cabriolet, 159K

Castrol LMA is a DOT 4 glycol-based brake fluid. Mercedes recommends DOT 4 brake fluid, and I've used Castrol LMA in all my cars for over 20 years.

All brake fluids are "synthetic" because they are "synthesized" in a petrol chemical process, but they are very different and will not mix with "synthetic" or any other motor oils.

Another commonly avialable DOT 4 is Valvoline Synthetic. "Synthetic" in this case is meaningless because all brake fluids are "synthetic" (including DOT 5 silicone-based brake fluid), but it probably has some "marketing value" to typical consumers who might think it's something special because of the name. It's just another DOT 4 brake fluid, and I would rather use Castrol LMA just because of this dumb, misleading name that Valvoline chose for their DOT 4 brake fluid.

Duke

Duke