Quote:
Originally Posted by Molez93
Technically this isn't related to my BRZ, but I've seen no responses in my BMW forums so I thought I'd see what general automotive insight you folks might have.
Any ideas on what's causing the water? Any suggestions for solving the problem?
I have 4%+ water in my brake fluid according to two ~$10 testers. Those same testers indicate 0% on fresh from the can brake fluid, so I'm inclined to trust the readings. I had similarly high readings before I completely bled the system about 6 months ago in Oct '19. The vehicle functions normally, but it (an X5M) is really just a daily driver so I'm not really hammering on the brakes like I would on a track car. There are no leaks, and the fluid is a decent amber color. A test strip suggests 0% copper, so I don't have obvious indications of internal metal deterioration. The only sign of issues was last Oct when one rear bleeder screw was corroded to a point where fluid wouldn't pass out the nipple- I bled the caliper by unscrewing the valve enough to drain from the screw itself.
Thanks to anyone who has any ideas!
|
Are you using this type of DOT 4 brake fluid tester to test for moisture content?
https://www.amazon.com/PTE-Tester-Ca...005HVG4GQ?th=1
The most accurate way of determining the water content in brake fluid is to have it tested by a garage that has a boiling point tester.
The main flaw with the cheap conductivity testers is that these testers will estimate the water content electronically by measuring the conductivity of the brake fluid, which in theory increases as water is absorbed. The tester then converts this measurement to a supposed boiling point and indicates the result using an algorithm as a display of green, yellow or red lights as % water, depending on the conductivity. Unfortunately, this measurement principle is fatally flawed as the conductivity of new brake fluids varies substantially from formulation to formulation within a DOT grade depending on the additives used. This means that unless a conductivity tester is calibrated on one manufacturer’s product and then used for that product only, it is likely to give very inaccurate results.
The maintenance schedule for my FR-S states to change the brake fluid every 30K miles (Normal), or 15K/15 months (Severe). My FR-S is 7+ years old but only has 28K miles on it. I recently had the brake fluid tested with a boiling point tester. Its moisture content was 1%. I suggest you do the same.