Have replaced the rear brake cylinders on my "72. Is there any difference in the way to bleed the rear lines since the cylinders are empty of brake fluid? Do I also need to bleed the front lines since they were not desturbed? And should I adjust the parking brake before or after I bleed the brakes? Thanks.

Any thoughts?

Unless the hydraulic fluid is less than 2 years old I would advise flushing and bleeding the entire brake system.

It can be as simple as opening all the bleeder screws and letting the old fluid drain through while topping up the M/C with fresh fluid.

When you see the new fluid emerging from the bleeders, close them off.

You can then do a conventional bleed at each corner to ensure the absence of air bubbles.

Rears first, longest line first, then fronts, longest line first.

I would also suggest you adjust the Emergency Brake prior to bleeding the rears.

^^^ what Nissanman said ^^^

This may help, as well:

http://www.classiczcars.com/forums/showpost.php?p=197062&postcount=13