What is involved in servicing a BMW brake fluid system?

Thursday March 14 2019


By Paul Kaganzi

Hello Paul, I recently bought a used 2009 BMW X5 from the UK and its information display shows that all service requirements are okay except brake fluid service, which is due. My question is, what is involved and can I do this brake fluid service at a petrol station service bay? Patrick

Hello Patrick, brake fluid service ought to be carried out every two to three years or as per the BMW brake fluid service counter. Brake fluid service for your BMW, like other modern cars, should be carried out by a knowledgeable mechanic using a special brake fluid bleeder and service machine.

There is a procedure to follow and safety precautions to bear in mind when handling brake fluid during this service. After the brake fluid service is carried out, a diagnostic tool has to be used to reset the brake fluid service counter.
The brake systems for modern vehicles work with brake efficiency enhancing systems such as the ABS (Anti-lock Brake System) or EBD (Electronic Brake Force Distribution).

These innovations require precision and prompt delivery of hydraulic brake fluid pressure. Brake fluid should be renewed because it ages with time and use. Brake fluid is a hydraulic oil, which is pressursed in the brake system to help engage the brakes and stop the heavy and often fast moving car. In other words, brake fluid is what is between your brake pedal and brakes that helps to stop your car.
Brake fluid is chemically designed to remain soluble with lubricating properties which flow around the brake system, protect moving components in the brake system such as pistons from metal shear damage or overheating due to friction.

Good brake fluid also has additives which reduce oxidation, inhibit corrosion and heat (heat disipator) to prevent damage, as well as maintain good performance of the brake system components.
Overtime and with use, brake fluid’s hygroscopic nature attracts moisture, while the corrosion and heat inhibitors or other additives age and reduce their protective and performance enhancing roles.