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sp53

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Hi all I am pretty sure that this is a well worn path, but when I was in the parts store buying dot 4 brake fluid, I noticed that the container now says synthetic brake fluid. I cannot remember the exact name of the brand, but it is the comman stuff. I want to say Castrol GTX or something (green, red and white bottle). Anyways has the product actually changed and if so would it be compatible with the old stuff. And most importantly if it is a new product does it still eat paint. I ask this because I think I am going to go with the silicone because it does not eat the paint.

Steve
 
Never really figured out what makes it Synthetic.
 
When I replaced all the components on my brake system, I changed over to Silicone brake fluid. I haven't had any complaints as of so far!

Im using DOT 5 silicone fluid
 
GreenOne said:
The synthetic fluid is a polyglycol based product that will supposedly still eat the paint, (I'm not going to experiment)
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Someone, I've forgotten who now, reported that they did try the experiment. They felt that it was slower to attack than conventional brake fluid, but it did eventually do a number.

And since I've seen paint apparently saved after a spill of conventional fluid; only to start bubbling with rust within a few months; I'd have to agree that only silicone is safe.

Of course, silicone has it's downsides as well. It actually protects the paint, maybe too well! I painted a wheel just last night that came up with a couple of "fish eyes", no doubt because it was contaminated with DOT 5 & I missed wiping down those spots with the special solvent.
 
DNK said:
Never really figured out what makes it Synthetic.
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Oddly enough, Castrol was involved in a legal dispute over that subject a few years back. The court's decision said in effect that "synthetic" and "semi-synthetic" were meaningless words, kind of like "fresh frozen fish".

IOW, anything that comes out of a modern petroleum refinery can be called "synthetic".
 
Looks like Randall and I posted nearly on top of each other.


DNK said:
Never really figured out what makes it Synthetic.
Click to expand...

It's man made.

Castrol won a lawsuit where their position was that anything that is made through a refining process is technically synthetic. The courts agreed so now they can slap the "synthetic" label on anything that's not pure crude.

There is a definite difference between "synthetic" and "silicone", although technically "silicone" is still "synthetic". Not everything that is "synthetic" is "silicone".

Castrol's DOT4 GT/LMA does say "synthetic" on the label but it also still declares that it is a "glycol" based brake fluid. As stated above, it will still harm paint. Although if you spill it, you can rinse it with water and it will disperse and be harmless. It helps if you know it spilled/leaked. It's when you don't know it spilled or leaked that it gets you.
 
sp53 said:
I noticed that the container now says synthetic brake fluid.
Click to expand...

It's always been synthetic. Its the same stuff as you used to buy. The only change is the label.
 
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