Brake help
You have to use a vacuum pump on the cylinder to bleed the cylinder. Because there is such a small amount of brake fluid being pumped when you squeeze the lever, many times you may have a small air bubble in the fluid chamber of the plunger and it wont allow fluid to go past. (It just keeps sucking in the bubble and trying to pump it back again). A tool called a MIGHTY VAC IS A HAND POWERED VACUUM PUMP AND IT WILL DRAW THE FLUID THROUGH THE MASTER CYLINDER AND INTO THE CALIPER. CONNECT IT TO THE BLEED PORT ON THE CALIPER AND JUST PUMP THE MIGHTY VAC AND IT WILL BLEED THE SYSTEM FOR YOU. iTS ALMOST LIKE PRESSURE BLEEDING A CARS BRAKE SYSTEM. If you play with the leaver of the master cylinder long enough, you may get it to start to pump fluid. Remove the brake line from the cylinder. squeeze the lever. Hold it in and make sure your finger is covering the outlet hole. release the lever. Squeeze it again and put your finger there again. release it when you have covered the hole again. Do this a few times and you may start to pump fluid. then connect the brake line and bleed it down to the caliper, opening and closing the bleeder each time you squeeze and release the lever. Just might work.