Brake fluid sludge

[DriverX]

Hi friends,

I recently did my own brake fluid flush for the first time. I used some of the online DIY/videos. Seems like everything has turned out well, pedal is less mushy.

I had a hard time discerning when there was a change in color between the old/new fluid - and I used a lot of new fluid. Next time I might use the blue fluid to see if it helps, but I heard that it can stain the reservoir.

Anyways, my main question was with regards to the reservoir. While emptying it, I noticed what I was taking out was full of floating "boogers" let's say. Then I peeked into the reservoir, and saw the filter was full of this white-ish sludge type of goop. I did my best to get it all out, but probably some was left behind. I couldn't figure out how to remove the filter so I just left it.

It all sort of floated to the bottom of my catch bottle. I couldn't see anything else suprising in the reservoir, and actually there wasn't much sludge in there.

But I am wondering, what is this sludge? I am sure it's a product of infrequent fluid flushes, as the last one was probably 4 years ago and "done"" by the dealer (I just came into possession of the car so don't blame me!). Should I be worried?

Actually what came through the lines at the wheels was sludge-free. I didn't even get much in the way of bubbles. Maybe some minute particles here and there that I really had to look hard to see, but that's all.

So far so good, for anyone on the fence about trying to DIY, it wasn't hard at all. Just took me a lot of time doing it for the first time.

Thanks everyone