Description Series 42 pumps are advanced hydrostatic units for medium power applications with maximum loads of 415 bar [6017 psi] (28/41 cm 3 ) and 350 bar [5075 psi] (32/51 cm 3 ). You can combine these pumps with a suitable Danfoss motor or other products in a system to transfer and control hydraulic power. The Series 42 variable displacement pump is a compact, high power density unit, using the parallel axial piston/slipper concept in conjunction with a tiltable swashplate to vary the pump's displacement. Reversing the angle of the swashplate reverses the flow of fluid from the pump, and reversing the direction of rotation of the motor output. Series 42 pumps provide an infinitely variable speed range between zero and maximum in both forward and reverse.
Sundstrand Sauer Danfoss series 42 of 42R, 42L Axial Piston Pump 42R28, 42R32, 42R41, 42R51, 42L28, 42L32, 42L41, 42L51
Details regarding the choice of hydraulic fluid     
The correct choice of hydraulic fluid requires knowledge of the operating temperature in relation to the ambient temperature: in a closed circuit the circuit temperature. The hydraulic fluid should be chosen so that the operating viscosity in the operating temperature range is within the optimum range - the shaded area of the selection diagram. We recommended that the higher viscosity class be selected in each case. Example: At an ambient temperature of X °C an operating temperature of 60 °C is set. In the optimum operating viscosity range (shaded area) this corresponds to the viscosity classes VG 46 or VG 68; to be selected: VG 68. Please note: The case drain temperature, which is affected by pressure and speed, is always higher than the circuit temperature. At no point in the system may the temperature be higher than 115 °C. If the above conditions cannot be maintained due to extreme operating parameters, please consult us.