Non Pressure Leaks
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2015 Jaguar XFR-S, 2015 Jaguar XFR, 2015 Jaguar XF, 2014 Jaguar XFR-S, and 2014 Jaguar XFR. However, it is still accessible from the selected car via links, so may be relevant.
Any reduced fluid volume in the brake master cylinder reservoir may be caused by two types of none pressure external leaks
Type 1: An external leak may occur at the brake master cylinder reservoir cap because of incorrect positioning of the gasket and cap. Reposition cap and gasket
Type 2: An external leak may occur at the brake master cylinder reservoir mounting seals. Repair such a leak by installing new seals and make sure that the brake master cylinder reservoir retaining bolt is correctly installed