Brake Fluid: Testing and Inspection
FLUIDDIAGNOSIS AND TESTING BRAKE FLUID CONTAMINATION
Indications of fluid contamination are swollen or deteriorated rubber parts. Swollen rubber parts indicate the presence of petroleum in the brake fluid. To test for contamination, put a small amount of drained brake fluid in a clear glass jar. If the fluid separates into layers, there is mineral oil or another fluid contaminating the brake fluid. If brake fluid is contaminated, drain and thoroughly flush system. Replace master cylinder with reservoir, caliper seals, Hydraulic Control Unit (HCU) and all hydraulic fluid hoses.