hi i was replacing my car battery and in doing so i noticed a trace of brake fluid in my brake master cylinder so i had repair it. i removed the two screws attached from the booster and the three tubing screws with ease. i successfully removed the cylinder from the car and now the hard part. i was able to remove the washer lock , pc of washer and rubber. but i cant seem to remove the whole piston. i saw a screw on the bottom of the cylinder and seems to me its a screw stopper . im afraid to remove the screw thinking it would be hard to put it back. can anyone tell me step by step on how to remove and install the piston . and how to bleed the cylinder manually with out using a bleeder system. thanks