A thrust bearing for use with a rotary valve is provided. The thrust bearing includes a journal portion and a thrust portion. The journal portion is sized to be disposed between a valve body of the rotary valve and a drive shaft of the rotary valve. The thrust portion is sized to be disposed between the valve body and a control member disposed within the valve body and movable relative to a valve seat disposed within the valve body via a drive shaft to control fluid flow through the valve body. The thrust portion includes a flat surface adapted to engage a corresponding flat surface of the valve body when the bearing is subject to a combined thrust and torsional load via the drive shaft, such that the bearing can accommodate the combined thrust and torsional load.