Green Brake Fluid - Page 2 - PeachParts Mercedes-Benz Forum

Duke2.6 · #1 04-30-2005, 07:31 PM

Quote:

Originally Posted by aNtHrAx323

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.

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

boneheaddoctor · #2 04-30-2005, 03:13 PM

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.

Kestas · #3 04-30-2005, 05:50 PM

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.