5 Brake System Flush FAQs
Here are some answers to FAQs on the brake system and brake fluid exchange:
1. What Is A Brake System Flush?
Like most fluids in your car, the brake fluid needs to be replaced eventually, usually as a precautionary measure.
Brake fluid can degrade by picking up dirt, metal, rubber debris, etc., over time.
To ensure your brake system has healthy and fresh brake fluid, a certified technician will conduct a brake system flush. This process basically removes all the old fluid from each brake line and replaces it with new, fresh fluid.
2. What Happens During A Brake Fluid Flush?
It’s best to take your car to an auto repair shop or a dealership, or contact a mobile certified technician to come over to your location for brake service.
During a brake fluid flush service, your certified technician or mechanic will:
- Find the brake fluid reservoir
- Drain out the contaminated, old brake fluid (helps remove air bubbles from the braking system too)
- Clean out the debris left in the braking system
- Check if the brake caliper, brake pad, brake rotor, brake pedal, or any other brake component needs replacing
- Replace your brake fluid with high-quality, new fluid (clean fluid)
- Remove the air trapped in each brake line with a bleeder
- Finally, do a proper brake inspection to check if the brake system is working right
3. Why Is A Brake Fluid Flush Necessary?
Your brake system is important for your safety. So if it isn’t in the best condition, you may compromise several working automotive or brake parts.
Many of these automotive parts are linked together using brake lines and hoses that use brake fluid to transmit and amplify forces. That’s why it’s necessary to maintain clean fluid to avoid hampering the functioning of any brake component.
A brake fluid flush service is also necessary to prevent moisture build-up. It can cause corrosion of metal brake parts like brake calipers, brake rotors, the master cylinder, etc., compromising the entire braking system.
A simple brake fluid exchange should prevent this corrosion of brake parts.
4. Why Does Brake Fluid Wear Out?
Brake fluid, a hydraulic fluid, is hygroscopic by its chemical design — meaning it absorbs moisture easily.
This is bad news for your brake system components as the master cylinder, brake lines, proportioning valves, ABS, and calipers are all made of aluminum or steel — metals that corrode due to moisture.
So, at any point the brake system is exposed to air (typically from the master cylinder reservoir), the brake fluid absorbs moisture. Eventually, the healthy, fresh fluid turns rusty brown or black due to corrosion inside the brake system.
As the fluid moisture increases, the brake fluid boiling point decreases, further reducing the efficiency of the bad brake fluid.
Note: Bad brake fluid is a common reason why the brake caliper and wheel cylinder start to seize.
5. What Does Brake Fluid Do?
When hitting the brake pedal, a plunger pushes against the master cylinder, transmitting fluid via the connected hoses to the brakes.
If you have a disc brake, fluid is pushed into a brake caliper. The brake caliper then presses a piston, squeezing the brake pad against the brake disc forcing your car’s wheel to slow or stop.
If you have drum brakes, the fluid is forced into the wheel cylinder, pushing the vehicle’s brake shoes against the drum to slow down or stop the wheel.
In both cases, brake fluid is integral in establishing effective communication between the brake pedal and the car’s brakes.