Corvus wrote:Tapio: what make the old fluid dirty and black?
Anybody's guess is as good as mine. I have no clue.
Maybe a previous owner put some fluid in there that really wasn't meant to be used as brake fluid? And it started dissolving O-rings and seals. The brakes work perfectly, though.
Now, iron corrosion comes in three shapes: FeO, FeO2 and FeO3. One of these are dark grey, or black. Don't remember which, but it's the one that is commonly put on gun barrels, to prevent rusting.
Maybe steel parts in the ABS/servo system had started to corrode?