I have a single axle EZLoader trailer with surge disk brakes. I had to replace the old metal brake line that was located in the framing as it had rusted holes in several places. I managed to somewhat get the brakes bleed after that but think there is still a little air in the lines. Any tips on how to bleed these?? How far should I be able to push the acuator in before it gets stiff and the brakes grab?? Any help would be greatly appreciated.