A hydraulic pump assembly including a first pump, a second pump, a shaft, and fluid lines is disclosed. The first pump includes a first piston assembly. The second pump including a second piston assembly. Each piston assembly of the first and second pumps includes a cylinder and a piston slidably disposed in the cylinder. The shaft connects the first pump to the second pump and is configured to displace the pistons within the cylinders of the first and second piston assemblies. The fluid lines fluidly couple the first piston assembly with the second piston assembly to form paired piston assemblies. The first piston assembly is phase shifted from the second piston assembly.

A hydraulic radial piston device includes a housing, a pintle having a pintle shaft, a rotor mounted on the pintle shaft and defining a plurality of cylinders, and a plurality of pistons displaceable in the cylinders. The radial piston device further includes a piston ring that provides an interface for the pistons. The radial piston device includes various configurations for improving the performance and efficiency of the device.