Substandard or Contaminated Brake Fluid
WARNING: This page is about a different car, the 2011 Suzuki SX4. However, it is still accessible from the selected car via links, so may be relevant.
Improper brake fluid, mineral oil or water in the fluid may cause the brake fluid to boil or the rubber components (piston cups and brake hoses) in the hydraulic system to deteriorate.
If the above fluid is included in the system, replace the master cylinder, reservoir and other rubber components (hoses). The master cylinder is disassemble parts to maintain the performance.
The system must be flushed if there is any doubt as to the grade of fluid in the system or if fluid has been used which contained parts that have been subjected to contaminated fluid.