A vane-type throttle valve assembly including a body having a passage therethrough and a pivotable shaft transverse of the passage and supporting a vane for variably restricting the flow of material through the passage. The shaft is disposed in opposing bores in the valve body. Each bore includes an access slot. The valve is assembled by inserting an integrated shaft and vane into the passage, engaging the ends of the shaft into the access slots, and translating the shaft ends in the access slots until the ends of the shaft are positioned in the bores. The shaft is retained in the bores by bushings inserted from outside the valve body. In a currently preferred embodiment, the access slots are formed over an angle from an axis of the bores, and the shaft ends are entered into the bores by rotating the shaft and vane about the passage axis.