Section 06-00: Brake System—Service | 1993 Mustang Workshop Manual |
An empty reservoir condition may be caused by two types of non-pressure external leaks.
Type 1: An external leak may occur at the master cylinder reservoir cap because of improper positioning of the gasket and cap. Reposition cap and gasket.
Type 2: An external leak may occur at the reservoir mounting seals. Service such a leak by installing new seals.