Went to change out the master cylinder, got a good look inside the resivoir, and the bottom is covered in sludge. Seperated the two, and there's a trace of sludge going into the m/c. I tried to clean the resivoir with brake cleaner, but couldn't get it clean enough. I'm replacing both.

What the heck would cause this. Should I be worried about the line's. Anyway to flush the system. Thank's.

 

There are 2 things that I know to cause this. One is from the fluid getting hot and the other is from mixing different fluids. The only way I know to clean the system is to either take the lines off at the calipers or wheel cylinders and let it flow out and then use a cleaner and keep flushing till it all comes clean.

 

Visit any auto parts store. look for a brake bleeder kit that includes a simple plastic hand pump. You'll need a clear plastic bottle, plenty of clean fluid and a buddy.

Attatch the hand pump to the bleeder valve and crack it open. While a buddy keeps the fluid level full, you simply pump till you see clear fluid come out.

Do all 4 wheels and your done. You'll need to bleed the system anyway so just keep pumping till it's clean.