Hi Rob,
Is the brake system holding pressure with the the engine running?.
I would be inclined to jack up each corner in turn, drop it onto an axle stand, start the car and then get someone to bury the brake pedal while you check for any seepage.
The abs system runs at a fairly consistent pressure, and as such, will put more load on the line connectors than just trying the system with the engine off.
Also, being an older design, and more of a pioneering ABS system, there is more potential for small air locks than a more modern system due to pipe run designs not being as well thought out as they are today.
All that being said, I would still have one in a heartbeat.