Brakes leak but no fluid on driveway?!

[bucannon]

So it's been a while since I've driven my 86 C10. Last time I drove it the right front caliper siezed, so now I have to address the issue it's had for a while. It has been leaking brake fluid from the front half of the resivour when sitting but I can't tell where it's leaking! There is no fluid that I can find on the ground.

Anyone ever have a similar issue?

I'm probably going to replace both calipers up front and the flexible lines when I get home from offshore (work). Would a bad master cylinder or booster be a culprit?

Thanks in advance guys