Hydraulic Power Assist Steering System problems of the 1999 Toyota Sienna

In early 2001, this vehicle had binding in steering, returning to center from left turns. Dealer repaired with kit from a service bulletin, at no charge, under warranty. At some point later in 2001, vehicle occasionally lost power assist turning left. Incidents are becoming more frequent. Both problems limit steering control, usually at low speeds, requiring fast driver corrections to avoid collisions. Arrangement is being made to diagnose and correct the latest problem. Both faults seem connected and should be studied, as they are safety hazards, and there was a service bulletin on the earlier problem that does not show up in the NHTSA data base.