If you own a BMW, you probably already understand that routine maintenance is crucial to help maintain the value and performance of your car. But when it comes to brake fluid, most people have no idea when or why it needs to be changed. It’s easy to ignore this necessity, and habit might have a good deal to do with it – a huge percentage of cars and light trucks in the U.S. that are over 10 years old have never had their brake fluid changed. If you’ve gone so long without having a problem, why start following recommendations to change your BMW’s brake fluid every one to two years in non-racing conditions?
There are lots of reasons to take this maintenance seriously. The worst case scenario resulting from neglecting regular brake fluid change is total brake failure, and the best case scenario is corrosion, which can result in costly repairs down the road. Your BMW’s stock brake calipers are cast iron, and water is not friendly to cast iron over time. Here are some of the basics to help you understand why this recommended frequency is crucial for your BMW.
What Does My Brake Fluid Do?
In a hydraulic braking system, brake fluid is used to amplify braking force by transferring force into pressure. This is mainly effective because liquid is very low in compressibility. There are several important characteristics that braking fluids need to have, but the main thing we’re going to focus on here is a high boiling point.
Because braking generates a lot of heat, it is essential that brake fluid have a high enough boiling point to resist boiling under intense use. This is because vapor (a result of boiling) is highly compressible relative to fluid, meaning it won’t transfer force in the same way and could result in brake failure if present in your system.
Why does my brake fluid need to be changed?
In short, brake fluid is hygroscopic, which means that it will absorb ambient moisture from air to which it is exposed. Moisture can even be attracted through microscopic pores in your rubber hoses, and your brake fluid could contain as much as 2% water after only a year. After 18 months this could be as much as 3%, and after several years your fluid could contain up to 7-8% water.
This water significantly reduces the boiling point of your fluid, and could lead to total brake failure. But even if your brakes never get hot enough to cause brake failure, the moisture directly causes corrosion throughout your system. Even without an increase in water content, heat breaks down your fluid by itself and gradually reduces boiling point.
Can I Flush it Myself?
While it may be possible to flush or bleed your brake fluid service on your own, it’s highly recommendable that you take advantage of the knowledge and experience of a performance and luxury car service professional like our experts at Euromotive Performance. Not only can it be time consuming to tackle on your own, but mistakes can cause bigger problems that really dig into your wallet. Our quality and affordable service will help you to avoid costly errors and keep your BMW at peak performance and value.
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Hopefully, you can see why it’s so important not to neglect regular brake fluid changes for your BMW. Don’t just stick it on your “to-do” list and forget about it for weeks – contact us now to set up an appointment.
