I just put new shoes on the front. Cleaned and lubed all moving parts, turned the adjusters in, and reassembled. I lost fluid when one of the pistons fell out so I think I let air in.
I've been bleeding them the same way I do my truck, but not having the same results. I keep adding fluid to the reservior, but don't build much pressure. The lever continues to bottom out against the hand grip. Am I doing something wrong?

 

The procedure is pretty similar to bleeding brakes on a car. Keep the reservior full. Pump up the brakes and hold pressure, open the bleeder and let out some air, close the bleeder, let up pressure on the brake and pump it up again and repeat until you don't get any more air and the brakes firm up.

I find it much easier and faster to use one of the hand vacuum pumps, like the Mity-Vac, though. It is much faster and easier.

With a motorcycle, and especially with a mountain bike, you have to be careful not to pump up too much vacuum or leave the bleeder open too long or too much, or you can suck all the fluid out of the master cylinder.