Thread: Just flushed brake fluid, and now dark again

Recently I flushed my entire brake system by removing all fluid from the master cylinder, refilling with new, and vacuum bleeding from each wheel until I saw clean fluid come out from each wheel. Afterwards I did some brake testing and took this picture:


You can tell the fluid was clean. Well now, the fluid is already brown again, not quite the same color it was before, though. The only reason I could think of why, is that the stuff that had lined the walls of the lines from the old fluid, has dissolved into the new fluid. Can anybody possibly explain why/how this happened? I may just flush once more since brake fluid is cheap. The hardest part would be jacking the car up and getting the tires on/off again.

We've had that happen a few times in the bikes we work on. If you don't do a pressurized flush, you'll never get 100% evacuation. Drive around for a bit more, and do another flush.

You'll likely never get it to be perfectly clear fluid, the insides of the brake lines arent new anymore so kinda like what happens when water stays in a metal pipe for a super long time, it turns black.

If the brakes work great and have no issues I would just leave it.

Originally Posted by Fivefingerdeathpunch

You'll likely never get it to be perfectly clear fluid, the insides of the brake lines arent new anymore so kinda like what happens when water stays in a metal pipe for a super long time, it turns black.

If the brakes work great and have no issues I would just leave it.

Well it hasn't been in there for even 2 weeks yet, the only reason I would think another flush may be good for it, is to keep the ABS pump from getting anything clogged. There is some of that stuff floating in the reservoir now. (The stuff that once lined the reservoir walls from old brake fluid)

Originally Posted by machinegunsquid

We've had that happen a few times in the bikes we work on. If you don't do a pressurized flush, you'll never get 100% evacuation. Drive around for a bit more, and do another flush.

I believe I got nearly 95% of the old stuff out, so the color that has changed doesn't represent 5% of the old stuff mixed with new. It's darker than that would be. I'll flush it once more when there's a day where I have nothing better to do. There will be one, I'm out of school now.

leave the brake fluid alone and instead worry about your ebcm working.

I'm not a fan of ABS. All of my experiences have been negative so far(winter stuff). The only situation I would like to have it, is when braking hard on dry pavement and the wheels slip. Rarely does that happen though.

I'm pretty sure they're original. I suppose that's possible as well, I didn't think of that. When replacing, I would like to upgrade to the stainless braided hoses if that's not too expensive.