i replaced my brake lines and at the same time i drained my master cylinder. inside was a nice black sludge coating everything. i cleaned it out but heads up to all you guys who never checked the brake fluid. btw brake fluid is clear and my old fluid was way black

 

it's pretty coommon. i think i read that dot3 brake fluid should be chanced every 3 or 4 years because of it drawing moisture into it. how many of us have ever changed brake fluid unless it was part of another repair? i'll bet next to zero.