A vital car maintenance tip is to check the condition of your brakes. The integrity of your brake system is determined by how well you maintain it.
What is a brake flush? A brake flush is a car service that involves flushing out the brake fluid from the master cylinder and replacing it with new brake fluid. This service gives your car a fresh start and helps to prevent multiple problems with your brake system.
A brake flush is recommended when you experience symptoms of a brake issue. Car owners need to understand why their cars need regular brake flush and car symptoms, which require a brake flush.
Importance of a Brake Flush
Although modern cars feature excellent brake systems, the systems are destructible. Like other car parts, the brake system is prone to deterioration with time.
The brake system’s master cylinder features rubber parts, which can become worn out with time. Other components, such as the wheel cylinders and calipers, are also at risk of degradation.
Some brake components may chip off and contaminate the brake fluid. Also, the joints may become covered with dust and metal chips from other parts of the brake system.
Multiple elements could contaminate the brake fluid and reduce its efficiency. Apart from the contaminants, the brake fluid itself can become degraded with time.
Chemical ingredients and additives in the brake fluid may become modified as they go through the brake system multiple times. As time goes by, the once clean brake fluid in your system will become contaminated and change color.
Moisture may also get into your brake system through rubber brake lines. Brake fluid with high moisture or water content heats up much faster than uncontaminated brake fluid.
Moisture may introduce air bubbles in the brake fluid, which may lead to spongy brake pedals due to the compressible nature of air bubbles.
Brake Performance
Many modern vehicles feature hydraulic brake systems, which can be adversely affected by changes in the brake fluid. For instance, contaminants such as dust and metal chips can affect the brake master cylinder and calipers, which may affect the overall performance of the brake system.
Problems with the brake system may affect both slow and fast drivers. Seemingly small issues with the brakes may have deadly consequences.
Symptoms Your Car Needs a Brake Flush
In general, the brake fluid should be changed every 20000 miles. However, some car manufacturers do not have any recommendations for when to change the brake fluid.
Consider changing your brake fluid if you notice problems with your brake system. A car with such issues will show multiple symptoms, including:
- Dark brown or black brake fluid
- A spongy-feeling brake pedal, which indicates the presence of air bubbles or moisture in the brake fluid
- Increased braking distance. Problems with the brake system may increase the braking distance considerably.
- In some cases, the braking distance may increase by 150-200 feet
These are signs your car requires a brake flush regardless of its mileage. Your mechanic should determine the exact cause of the brake problems and provide solutions.
How Often to Change the Brake Fluid
The recommendations for how often to change the brake fluid vary depending on the car brand and model. Some provide suggestions for changing the brake fluid based on mileage while others base their recommendations on time.
For instance, some car models require a brake flush after every 20000-45000 miles. Other car manufacturers recommend a brake flush after every two or three years regardless of the mileage.
Car owners should consult their manufacturers for recommendations on when to change brake fluid. The brake fluid is usually in a watertight container and may last for years if it is not contaminated.
Effects of Brake Fluid Contaminants
Contamination of the brake fluid occurs when air, moisture, or other contaminants work their way into the brake fluid through different parts of the brake system. Contaminated brake fluid loses its performance and efficiency.
Moisture in the brake lines can increase stopping distance because it increases air bubbles in the brake fluid. In addition, water lowers the boiling point of the brake fluid, which affects its efficiency.
With time, water causes the internal components of the brakes, including the lines, cylinder, and calipers, to corrode and rust. A brake flush is a relatively affordable car service which can save you significant amounts of money on repairs.
Cost of a Brake Flush
The cost of a brake flush may range between a few hundred dollars to a few thousand dollars depending on the car make and model. Consider having your brake fluid tested for moisture and other contaminants every few years, especially if you live in high humidity or wintry area.
Dark looking brake fluid is a reliable visible sign of contamination. Fresh brake fluid has a light brown color but usually darkens with time.
Types of Brake Fluids to Use
There are different types of brake fluids to use on your vehicle. Each type has distinct dry and wet boiling points.
The dry boiling point is the boiling temperature for brake fluid, which does not contain moisture. On the other hand, the wet boiling point is the boiling temperature for brake fluid with about 4 percent moisture or water in it.
It takes about two years for brake fluids to absorb 4 percent water. Therefore, doing a brake flush every year or so is essential.
You can use different types of brake fluids on your vehicle, depending on manufacturer recommendations. Common types of brake fluids include:
- DOT3 (Glycol-based)
- DOT4 (Glycol-based)
- DOT5 (Synthetic-based)
- DOT 5.1 (Glycol-based)
DOT 3 and DOT 4(Glycol-Based)
Many vehicle manufacturers recommend DOT 3 and DOT 4 brake fluids. Both types of brake fluids are glycol-based.
These types of brake fluids have high boiling points and are ideal for heavy-duty use. DOT 3 and DOT 4 brake fluids have wet and dry boiling points of approximately 311 degrees Fahrenheit and 466 degrees Fahrenheit, respectively.
DOT 5 Synthetic (Silicone-Based)
This recently developed brake fluid has boiling points of at least 500 degrees Fahrenheit. One of the benefits of DOT 5 brake fluids is it does not absorb as much moisture as DOT 3 and DOT 4 brake fluids.
DOT 5 brake fluid does not require frequent changing and may cost three to five times as much as DOT 3 and DOT 4 brake fluids. However, this type of brake fluid is not recommended for ABS systems because it is prone to aeration when cycled through the brakes of an ABS.
This type of brake fluid is recommended for trucks and heavy equipment, which do not use ABS. Also, DOT 5 is not compatible with DOT 3 and DOT 4 brake fluids.
DOT 5.1 (Glycol-Based)
This type of brake fluid has some of the characteristics and benefits of DOT 5. However, DOT 5.1 is glycol-based and is compatible with DOT 3 and DOT 4.
Pressure Bleeding vs. Manual Bleeding
The two main methods of brake flush service include:
- Pressure bleeding
- Manual bleeding
Pressure bleeding uses canisters with built-in pumps to remove brake fluid and air. Once the pressure bleeder has been connected to the brake fluid chamber, the user pumps up the pressure by hand.
The user then opens up the brake bleeder screws to force fresh brake fluid from the pressure tank to enter the brake fluid lines while forcing the old fluid out. One person can quickly do this job because the bleeder unit does most of the work.
Manual bleeding becomes necessary, especially when you do not have a pressure bleeder. As the name suggests, this method does not use a pressure builder.
At least two people best do manual bleeding with the second person pumping the brake pedal at specific intervals.
References
https://static.nhtsa.gov/odi/rcl/2015/RCRIT-15V337-5337.pdf
https://www.firestonecompleteautocare.com/repair/brakes/brake-fluid/