The paper presents theoretical work carried out with the simulation program Bathfp. Models simulating the dynamic behaviour of axial piston pumps have been extended to investigate piston forces for different valve plate timings and for different swashplate angles. These forces have then been used to calculate the mean and fluctuating components of the moment functions. Since the forces and moments together are the most important inputs causing structure borne noise, the influence of the swashplate angle on the structure borne noise could be investigated. The influence of the suction port timing on both structure borne and fluid borne noise potential is also discussed.