cosworth abs
I have fitted the cosworth brakes to my kit car with the abs manifold but without the abs wiring.
When I first fitted it I had the pump running all the time this caused the pedel to go hard and push your foot back as it overpressurised the system and the pump got hot.
The way round it was to wire in the presure solenoid so that when it reached its pressure it switched of the pump.
The brakes work by charging the accumulator [ the black ball on top of the pump] which stores pressure. Once up to pressure the pump switches of and the accumulator takes over untill it needs charging again and then the pump starts again. So it looks to me as though the pressure switch has gone or the pump has been indipendent from the switch.
Hope this is of some help.
Paul.