Brake Master Cylinder
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.
Usually, the first and strongest indicator of anything wrong in the brake system is a feeling through the brake pedal. In diagnosing the condition of the brake master cylinder, check pedal feel as evidence of a brake concern. Check for brake warning lamp illumination and the brake fluid level in the brake master cylinder reservoir