In this condition, brake fluid may leak from the seal, or a small amount of air may enter the master cylinder, which could lead to an increase of vehicle stopping distance.
Service Brakes, Hydraulic — Foundation Components — Master Cylinder
Certain passenger vehicles have the possibility that the recess retains a rubber seal ring, which is located at the end of the cylinder body, and may be corroded due to an improper washing process.
Dealers will inspect the brake master cylinder and, if necessary, replace the brake master cylinder and booster. The recall began on November 29, 2004. Owners should contact Toyota at 1-888-270-9371.