TOYOTA IS RECALLING CERTAIN MODEL YEAR 2005-2006 AVALON, MODEL YEAR 2004-2006 HIGHLANDER, MODEL YEAR 2004-2006 LEXUS RX, AND MODEL YEAR 2006 LEXUS GS AND IS VEHICLES. BRAKE FLUID CONTAINING POLYMERS IS USED THAT ACTS AS LUBRICANTS FOR CERTAIN BRAKE SYSTEM COMPONENTS. IF REPLACEMENT BRAKE FLUID IS USED THAT DOES NOT CONTAIN SUCH POLYMERS, OR THAT CONTAINS ONLY SMALL AMOUNTS, A PART OF THE RUBBER SEAL LOCATED AT THE REAR OF THE BRAKE MASTER CYLINDER MAY BECOME DRY, AND THE SEAL MAY CURL DURING MOVEMENT OF THE PISTON. IF THIS OCCURS, A SMALL AMOUNT OF BRAKE FLUID COULD SLOWLY LEAK FROM THE SEAL INTO THE BRAKE BOOSTER.