A torque arm assembly, used with a solar collector mounted to a drive shaft, comprises a torque arm with first and second ends and a torque arm coupling assembly including a drive shaft enclosure defining an open-ended channel sized to house the drive shaft. The channel has a circumferentially extending substantially continuous drive surface between the ends that lies adjacent to the drive shaft so the drive shaft and the drive shaft enclosure rotate together. In some examples contiguous abutment structure, such as weld lines, shims and/or adhesive, connects each side of the drive shaft to the drive shaft enclosure. The invention may also be carried out as a connection improvement method.