1997 GMC Suburban brake bleeding problem

Replaced the pads on the front brakes no problems. Then removed most of the old fluid from reservoir and refilled, bled the right front and after a normal amount of air I got good clean fluid. The left front same except I keep getting air and quite a lot. I ran through a small bottle trying to get the air out no luck. I tried to get all the air out until I ran out of new fluid. Ii bought a big bottle and the next day started again with the RR then LR then FR all was normal but cannot get the air out of the left front. I do not see any leaks, it does have anti lock.