Abstract: The invention relates to an improvement in the spring arrangement of the control valve assembly of a hydrostatic steering unit of the type having a measuring motor and relatively rotatable inner and outer concentric tubular valve members. In this type of unit one of the valve members is connected to the motor and the other valve member is manually rotated for steering purposes. The valve members have axially aligned and diametrically arranged slots for housing the spring arrangement which includes a pair of curved leaf springs and two supporting plates which may also be leaf springs.