sounds like the ABS pump was running continuously and over pressurising the system..
Check the condition of the connectors and their contacts around the brake master cylinder and pump, especially the 7-pin one on the pressure switch, it is this switch that turns the pump off when the system reaches working pressure, via a relay, and if it isnot making good contact it can allow the pump to overrun.
I've had this once myself, but never did it again to absolutely trace the fault, But I think this was the reason.