Of course the fluid in the reservoir on top mixes with the fluid in brake lines over time. It is just you can only remove a limited amount of fluid from the top. My guess it is less than a 1/4 you can remove from the top without risking introducing air in the system.
I don’t know if it is true that water tends to accumulate at the lowest point and not mix with the rest of the fluid. There are testers that you stick In the brake fluid reservoir to measure water content in the fluid to determine if the fluid is good. If water accumulated only at the bottom these testers would be pointless.
I don’t know if it is true that water tends to accumulate at the lowest point and not mix with the rest of the fluid. There are testers that you stick In the brake fluid reservoir to measure water content in the fluid to determine if the fluid is good. If water accumulated only at the bottom these testers would be pointless.
