There are several methods to bleed brakes. On a tough one like you have I use a clean glass jar with brake fluid in it. I take a piece of tubing, clear is best making it easier to see bubbles, put one end of the tube on the bleeder with it open. Put the other end in the jar making sure it stays under the level of the fluid. Pump the lever watching for air in the jar, once there is no more air you should be good to go. Be sure to keep fluid in the reservoir during the process or you will introduce more air into the system. Once bled you may have to tie the lever back over night if you still do not have a good feel.

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