Regularly changing your car's brake fluid helps to maintain brake system integrity, and could even give it a totally fresh start sometimes. Topping off or changing your brake fluid may solve some braking issues, but eventually a brake flush will be needed to achieve the right results.
What is a Brake Flush?
A brake flush involves removing all of the brake fluid from the entire brake system and replacing it with new, clean brake fluid. This is not to be mistaken for brake bleeding, which only removes a portion of brake fluid in order to remove bubbles that may have formed in the brake lines.
Why is a Brake Flush Important?
Your brake system contains many components, all of which are at risk for deterioration. Rubber parts can rot (especially in the South Texas heat). Wheel cylinders and calipers are hydraulic parts that eventually wear out. Some parts may chip and release material fragments into the brake fluid. Dust and brake material particles can find their way into and contaminate brake fluid, and the fluid itself will degrade and become dark and dirty over time.
Moisture can enter the system through rubber brake lines, combining with the brake fluid and introducing air bubbles by way of lowering the boiling point of the fluid. Air bubbles are compressible, and can make your brakes feel spongy and unreliable.
Changes in the hydraulic fluid (aka brake fluid) in modern hydraulic brake systems can alter braking performance. Debris or particulates in the brake fluid can weaken the brake master cylinder and may affect the rubber seals on the calipers themselves, leading to reduced braking power. For slower city street drivers this isn't usually an issue, but it can lead to catastrophic brake failures at highway speeds.
What Symptoms Warrant a Brake Flush?
For most vehicles, it is recommended that brake fluid is changed every 2-3 years or 20k-24k miles. There are other situations, however, that may warrant a brake flush in the interim:
• Visible contamination/discoloration of the brake fluid.
• Spongy (or otherwise odd feeling) brake pedal.
• Increased braking distance. For example, a car should be able to come to a complete stop from 60mph in about 150 feet. Reduced braking power can significantly lengthen the distance needed to come to a stop.
If you're experiencing any of these symptoms, it's probably time for that flush, regardless of how many miles or years it's been since it was last performed. Of course these may also be symptoms of other problems, a qualified technician should be able to help you find the cause.