52 are approximately 1 10 horsepower approximately 1 000 rpm a suitable pump speed is 1 10 rpm to provide about a 10 minute cycle period the reduction gearbox should reduce input to the pump from the output of the motor shaft in this example at a ratio of 10 000 1 generally speaking reduction gearing of at least 1 000 1 will be used in the invention usually reduction gearing in the range of 3 000 1 to 30 000 1 depending on the operating speed of the electric motor 52 a motor and gear head made in japan by oriental motor co ltd was tested with good results after some modification to provide a higher gear ratio a preferred pump used according to the invention is illustrated in fig3 through 7 the pump can be easily set up to provide two or four master cylinders the pump includes a housing 70 defining a pair of parallel cylinder bores 72 in the illustrated embodiment the housing is split into two halves 71 and 73 it is preferred that the two halves be identical the cylinder bores 72 are positioned in a side by side relationship each cylinder bore is provided with a closed end 74 which at least partially defines a hydraulic fluid master chamber 76 the chambers 76 are connected to the fluid flow lines 56 through fittings not shown positioned in passages 69 extending through the closed ends 74 of the cylinder bores the housing further at least partially defines a crankshaft receiving borehole 78 positioned between the parallel cylinder bores 72 the crankshaft receiving borehole is directed at a right angle to the direction of the.