Flush the system if there is any doubt as to the grade of the fluid in the system or if the fluid has been used which contains the slightest trace of petroleum or mineral based fluids. Replace all rubber parts (including the brake hoses) that have been exposed to contaminated fluid. Approximately one quart of fluid is required in order to flush the hydraulic system. Use the steps specified in the pressure bleeding procedure or the manual bleeding procedure. Refer to Hydraulic Brake System Bleeding .