Re: Old Brake Fluid

Posted by HH56 On 2010/9/5 9:51:52

Could be brand specific but on the brands I have used, there is quite a pungent odor to the DOT 3 and 4--hard to mistake for anything else-- whereas the 5 has a much milder smell-almost like an oil. Dot 5 silicone is usually a little thinner in viscosity with a purplish tint while the older 3 & 4 is more clear to amber. Of course, if it has been in the system a long time then age and use will have taken care of that.

Not sure about the new paint formulations but if you have an old piece of scrap painted metal, a few drops of the silicone will not affect it much whereas the older fluid will discolor the paint and start to lift it off after a while.