The reasons for higher water content and darker color in your brake fluid are twofold:
1.- The higher the mileage, the higher the internal wear on the brake lines, especially the flexible ones on each corner. Also some debris, mostly brake dust, gets passed by the dust seals on the calipers.
They are responsible for the darker color due to the tiny rubber particles in suspension.
2.- The higher the wear on the components as described, the easier it is for the very hygroscopic fluid to draw in water molecules (trough the flexible brake lines) and into the brake fluid.
Flushing the brake and clutch fluid every 2 years or sooner (if tracked) will keep the fluid cleaner and with less H2O content.
Replacing the brake lines (after 15 years) with steel-braded lines also keeps the fluid with less water content because of the different liners used in these lines.
Happy Boxstering,
Pedro
Pedro Bonilla1998 Boxster 986 - 311,000+ miles:
[www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)
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