I have a 2018 Mazda cx-5 sport trim with about 130k miles AWD a/t. I recently had the brakes done at a shop and they keep recommending to do a brake flush. As fad I know the brake fluid is the same as it left the factory. I was taught that brake flushes should only be done if the master brake cylinder or the abs module needs to be replaced. Has something changed. Or is it just a money maker?
As fad I know the brake fluid is the same as it left the factory.
That makes it 7 years old.
I was taught that brake flushes should only be done if the master brake cylinder or the abs module needs to be replaced
You were taught wrong, though certainly many people don't bother changing it. Brake fluid does not require frequent changes but there is good reason to change it periodically. As I'm sure you know, brake fluid absorbs moisture which can cause corrosion. There are test strips that can be used to tell you whether moisture content is too high. Some prefer to change the fluid on a regular schedule, usually every 5 to 10 years.
yeah you need to put in new brake fluid every now and again. If you don't, it rusts out your brakes and brake lines from the inside. It also gradually gives you spongy brakes. It's something to think about doing at around 100k miles.
https://goodyearbrakes.com/brake-pads/winter-is-coming-watch-out-for-moisture-in-your-brake-fluid/
I recently had the brakes done at a shop and they keep recommending to do a brake flush. As fad I know the brake fluid is the same as it left the factory. I was taught that brake flushes should only be done if the master brake cylinder or the abs module needs to be replaced.The shop is likely trying to drum up service work. You'll find all kinds of answers about this because many people haven't touched theirs in decades, while others cite their owners manual which suggests changing it every couple of years. Brake fluid will last a very long time, unless it becomes contaminated, then you do need to change it. Test strips are available locally for testing if it's a concern. I change mine every 5-6 years or so simply because I believe in changing all fluids periodically, regardless of the mileage accumulated.
@hixster the test strips cost $50 though. A fresh bottle of fluid costs $10.
Brake fluid is hydroscopic (it absorbs water over time). The braking system is also not perfectly sealed. The boiling point of DOT 3 brake fluid it around 400 degrees Fahrenheit when pure. The boiling point drops over 120 degrees when contaminated by water. If you drive at highway speed down long inclines, you're going to step on the brake to limit your gained speed. Your brakes will be less effective due to the reduced boiling point of the mixture if you never change it. You'll know when that occurs. Normally, brakes are firm. As you ride the brakes going downhill, the boiling point of the water is a lot less than the DOT 3, causing the brake fluid/ water combo to start boiling, and the brake pedal becomes mushy, a phenomenon known as brake fade. That is unsafe, because the car will take longer to stop in an emergency.
Do a visual check. Most brake master cylinders have a see-through brake reservoir. When the brake fluid starts becoming dark, that's a sure-fire way to tell your brake fluid needs to be changed. As others have mentioned, though. Brake fluid absorbs moisture, and moisture eventually leads to your brake lines rusting from the inside. Personally, I'd make it a habit of changing it every once in a while. Your brake lines will last much longer.
Thank you all for your help. I feel better not doing it at this time. Maybe the next brake job