Very good the matter is that the clous dump-bomba was installed new to a Ford Explorer XLT Model 99, the Are from the hydraulic system was taken by means of operating the pedal and also by gravity method and the pump does not show results and continues with air, how could you take the air out of the hydraulic system?
Try disassembling the central pump and lowering it as much as possible but connected the pipe to the level of the Cluch balinera, so that the air does not return to the central pump but accumulates on the balinera and act with the hand as normal. Aol exit the air, the sleeve will get hard and it does not access more and mount the central pump sealing the filling plug so that it does not between the system.