Rear Disc Brake

Rear Disc Brake

COMPONENT LOCATION

NOTE:
RH (right-hand)
SC (supercharger) vehicle installation shown, other installations similar.









INTRODUCTION
The rear braking system on both the naturally aspirated and SC (supercharger) vehicles features ventilated brake discs with single piston sliding calipers. On naturally aspirated vehicles the discs are 326 mm (12.83 in.) diameter x 20 mm (0.79 in.) thick. On SC (supercharger) vehicles the discs are 376 mm (14.80 in.) diameter x 26 mm (1.02 in.) thick.
The brake disc is manufactured from cast iron. The disc is retained on the wheel hub by two retaining washers and the wheel nuts.
Each caliper is mounted within a fixed carrier that is secured to the rear wheel knuckle with two bolts. The brake calipers on SC (supercharger) vehicle are painted and also include a badge. The badge must be removed in order to renew the brake pads. Each inboard brake pad is installed with a wire anti-rattle spring. The inboard brake pad of the RH (right-hand) brake incorporates a wear sensor.

NOTE:
New pad wear sensor leads need to be fitted whenever the brake pads are changed irrespective of the brake pad warning sensor being triggered.
The brake pad wear sensor is wired in series with a wear sensor on the LH (left-hand) front brake and the instrument cluster. If the thickness of one of the brake pads connected to a wear sensor decreases to a predetermined limit, the instrument cluster illuminates the brake warning indicator.
Also incorporated into each rear brake caliper carrier is the parking brake mechanism. For additional information, refer to Parking Brake

Repairs

CAUTION: Do not use the 'Emergency Release' tool to allow work to be carried out on the rear brakes. Work can only be carried out on the rear brakes after the 'parking brake unjam' routine is run.
Before carrying out any work on the rear brakes, the Jaguar approved diagnostic system must be connected and the 'parking brake unjam' routine run. For additional information, refer to Parking Brake Cable Tension Release Service and Repair
When all work is carried out on the rear brakes, the parking brake system will require resetting. For additional information, refer to Parking Brake

CONTROL DIAGRAM

NOTE:
A = Hardwired









PRINCIPLES OF OPERATION
When hydraulic pressure is supplied to the caliper, the piston extends to force the inner pad against the brake disc. The caliper reacts and slides along two guide pins to bring the outer pad into contact with the brake disc.
When a brake pad incorporating a brake pad wear sensor is approximately 75% worn, the brake pad wear sensor goes open circuit. When the instrument cluster detects the open circuit, it illuminates the amber LED (light emitting diode) in the brake warning indicator, displays an appropriate warning in the message center and sounds a warning chime. For additional information, refer to Instrument Cluster