If you can hear air leaking out of the bottles when you squeeze them, those bottles will never carbonate. I strongly recommend using caps that are not screw on, as these have a much better chance of sealing properly. You of course can always crank down the screw caps as tight as possible, but even then CO2 might be able to escape. Depending on how much sugar is in each bottle, what temperature they're at, how long you waited to bottle after fermentation, and what yeast you used on that batch it could take 5-6 days to carbonate, or 2.5-3 weeks. 70*F with 4oz. Corn Sugar/5 Gallons and no matter what yeast you used you should be fully carbonated in 2 weeks.