Need Help with soft brakes
 

Ok so I changed all my brake pads on my 88 GXL with 4 piston calipers and rear pads also, I also flushed my brake fluid till clear fluid was flushed through. But now I cant get the brakes to pump up and stay pumped they just loose pressure after a second or two, I bled them in RR, RL, FR, FL and checked all fittings for leaks and bleeder valves. The only thing that concerned me was a torn caliper boot on the RL caliper. I also used the correct tool to compress my brakes if that matters. And yes I recruited someone to operate the pedal for me. I even had a guy at auto zone tell me to bleed a line into a cup of fluid untill there was no fluid in the hose attatched to the bleeder valve and keep the bleeder valve open and rapidly pump the fluid then tighen in while they are pumping on all four calipers still nothing.