Brake master cylinder leakage

[small boy]

Hi,my front brake fluid resivoir is seaping around the cap,i have taken it off and the seal seems ok,there is a white crusty 'stuff' around the inside of the cap,any ideas................:puzzled:

[nelly]

Usually it's because it's too full. Don't go any higher than mid point between min and max.
Fill it up to max and the fluid creeps on the seal, gets to the cap and lifts the paint.