Fuel Pre-Filter Plastic Line

[pat201]

I just replaced all plastic fuel delivery and return lines (including the fuel pre-filter seal & fuel filter). However after 10-15 cranks there is only air and no fuel in the plastic delivery line which comes to the pre-filter. All other lines (five of them - six in total) show that they have fuel.
How many other cranks should I try before the air is removed by the pump? I am concerned that I may have done something improper.