Much of the advice I see here is good but it requires equipment and materials that the average do it yourselfer doesn't have. If the only reason it's empty is because you removed the compressor, it should still be vacuumed before you reacharge it. My advice would be to compare the cost of buying what you need to do it properly at home vs. having a shop evac. and charge it for you. Gauges, a vacuum pump, freon, pag oil, etc. would likely cost more than a simple evac/recharge at a shop. Also you asked about the system's capacity. It's 30 oz. for a 98 Ranger but you'd still be taking a chance if you don't vacuum it first and you wouldn't know the exact readings without gauges. Shame that you're like some 1800 miles or so away. I could help you out because I have all of that stuff at home.