Spongy brakes

[Dingusthe]

So in my auto shop class in high school I brought my truck in to do the front pads, I changed the pads, retainers but I pulled the caliper all the way off to clean them. They go back on fine, I gravity bled them and then pressure bled them, they are as hard as rock, start the truck up, no brakes at all we tried using the abs bleeding system still nothing. We tried bleeding them with the truck running and it just went to the floor and no fluid came out and trust me the master cylinder reservoir is at the full line. 

Thanks,

Ed

P.S. 2013 Silverado 1500 LT Drum brakes in the rear, We did NOT bleed the rear brakes since we didn’t touch them.