My rear brake is like new again! Here's how I did it.

As my previous post says, I rebuilt the rear master cylinder a few weeks ago. The rebuild went fine, but the pedal feel was still soft and the pedal travel was long. The brake felt strong enough to be serviceable, but definitely not fully there. On advice of a fellow Sportster owner I tried the following. I gently pushed the caliper piston all the way back by using a large screw driver between the pad and the rotor. It is not hard to do if the caliper is in good shape. Does not take much force. I then jammed the pad with the screw driver so that the piston would stay pushed in when I apply brake pressure. I then proceeded to bleed the brake the old fashioned way:

1. Open the bleeder
2. Gently push the brake pedal
3. Close the bleeder
4. Release the brake pedal

I repeated the above steps three times, then added some brake fluid to the reservoir and pumped the pedal with the bleeder closed a few times. The pedal travel became mush shorter and the feel became much firmer. I then removed the screw driver from between the brake pad and the rotor and gently pumped the pedal until the piston came out to meet the rotor. The pedal feel and travel remained good. Went for a ride and was amazed at how much better the brake felt. I would say it's 100% back to normal now.