There are of many different of opinions and misconceptions concerning the need for periodic brake fluid flushes.
Do I Need a brake fluid flush? How frequently should it be flushed and Why?
Most German car manufacturers recommend having your brake fluid flushed every couple years. Brake fluid is hygroscopic which means it attracts and holds moisture be absorbed right out of the air.
Old, contaminated brake fluid on the left vs. fresh fluid on the right.
Brake fluid moisture can be seen by darkening of the brake fluid .I can be very easily measured with brake fluid moisture tester. Brake fluid should not boil until approximately 500 degrees with just 2% moisture the boiling point can be compromised up to 45% around 320 degrees.
When your car feels like it does not stop as well after a few stops your fluid could be ready to be flushed.
As brake fluid ages it’s going to corrode in many of the hydraulic components found in the braking system|.
Additionally, the ABS (Anti Lock Braking System) hydraulic unit, seals and hoses used in the braking system slowly deteriorate causing small rubber particles to be suspended in the brake fluid.
Antilock brake systems (ABS) have little passageways in their pumps and control valves that are readily plugged from the suspended corrosion and rubber particles. That dirty fluid will lead to endangered braking operation. Replacing your brake fluid at the proper time intervals will help maintain your braking system and prevent more costly repairs down the road.