OK, I went to go top off my brake fluid on my 96 S-10 Blazer. First off...there was nothing in the little rubber container thing that sits on top the little tank thing...if u lift up the rubber thing, I can see fluid there...its dark. Not black, but dark. (This is DOT 3) The new DOT 3 brake fluid is clear...which it should be. But can i still top it off and mix the 2 colors? Do I just add it to the little black rubber thing with the 2 indentions, or do I lift out the rubber pad and fill that to the max line?