What are the methods for changing brake fluid?
3 Answers
Methods for changing brake fluid include using a vacuum oil extractor to remove the old brake fluid and then adding new fluid, or using a brake fluid changer for replacement. Effects of long-term non-replacement: If not replaced for a long time, brake fluid can corrode the braking system, posing significant safety hazards; the boiling point of brake fluid decreases after absorbing moisture, which can easily lead to insufficient braking pressure and affect braking performance; deposits and impurities in the brake lines can cause brake system malfunctions and impair braking efficiency. Functions of brake fluid: It effectively lubricates the moving parts of the braking system, extending the service life of brake calipers and seals; it adapts to various environments, ensuring the flexible transmission of braking force under conditions such as high temperatures, extreme cold, high speed, and humidity.
In my car club, I often see three methods for changing brake fluid. The simplest is the gravity method, where you open the cap of the brake fluid reservoir and let the old fluid drain out on its own, then pour in new fluid. This method is cost-effective but doesn't completely replace the old fluid, as some residue always remains. The intermediate version uses a hand-pressurized fluid changer connected to the brake caliper, pushing new fluid in while draining the old fluid, which results in a cleaner change. The most professional method is the machine pressure method, where specialized equipment at repair shops can change the fluid for all four wheels simultaneously, completing the job in five minutes without introducing air. I recommend changing it every three years or 60,000 kilometers; otherwise, the spongy brake feel can be quite alarming.
Last time I DIY changed my brake fluid, I figured out a few tricks. The most common method is the two-person pedal pumping technique: one person sits in the driver's seat to pump the brake pedal while another operates the bleeder screw near the wheel - pump once, release some fluid, until the fluid coming out turns clear. Remember never to let the reservoir run dry during the process, or air will get into the lines and cause trouble. There's also a makeshift method using a syringe to extract old fluid, but this is only suitable for temporary emergencies. Important reminder: never mix different brands of brake fluid - DOT4 and DOT5.1 have different formulations that can cause chemical reactions.
