2008 Heritage. The rear brake is not working at all. I don't see any fluid leak. The pedal is very light and goes all the way down without any braking. Where shall I start? On my Roadking the reservoir is close to the brake pedal,but on softailI don't see it.

 

The reservoir should be just next to the brake pedal. Check the level, fill, and bleed. Not hard. Would help to have a manual. Your reservoir might be cracked. That happened to me when I hit a squirrel.

 

Like Gman said, the issue is probably related to either low fluid or more than likely air in the system.

For some reason I seem to have to bleed my brakes about once every year.
The pedal over year's time frame progressively softens up.
I've just added this to my "to do list" when I'm changing the fluids.

I'm guessing that my problem is a weak seal at the reservoir , but also like Gman said, bleeding the brakes is easy and only takes a few minutes once you have the "tube", "wrench" and bottle of fluid handy.

Also like Gman stated, if you haven't already it's time you drop $60 on a service manual.