Brake fluid is black or brown Inspection
Dark, brown, or black brake fluid on your dipstick or reservoir? A brake fluid inspection measures moisture contamination, degradation levels, and rubber seal wear to protect your master cylinder and ABS system.As water mixes with the fluid, the boiling point drops dramatically, increasing the risk of vapor lock during heavy braking. The fluid turns dark brown or black as internal temperatures bake the mixture and breakdown products dissolve internal rubber seals, flexible brake lines, and master cylinder cup seals into fine particulate sludge. Dark fluid also contains dissolved copper and iron particles from oxidizing steel brake lines, which can form abrasive sludge that jams sensitive solenoids inside expensive ABS control modules.