Land Rover Discovery: Parking Brake and Actuation / Description and Operation

COMPONENT LOCATION

NOTE:

Right Hand Drive (RHD) illustration shown, Left Hand Drive (LHD) illustration similar

1. Integrated Anti-lock Brake System (ABS) control module and Hydraulic Control Unit (HCU)
2. Instrument Cluster (IC)
3. Right Electric Park Brake (EPB) actuator
4. Left EPB actuator
5. EPB switch

OVERVIEW

The Electric Park Brake (EPB) is an electrically actuated system that operates the calipers on the rear brakes. The system consists of:

• An EPB switch
• Two EPB actuators
• Clutch pedal position sensor (manual transmission vehicles only)
• Two warning indicators
• Anti-lock Brake System (ABS) control module

The EPB is controlled by the ABS control module, which uses the EPB actuators to apply and release the rear disc brakes. Operation of the EPB is initiated by the EPB switch and software within the ABS control module. The EPB has the following operating modes:

• Static apply/release
• Ignition off apply (manual transmission vehicles only)
• Drive away release
• Automatic transmission apply/release
• High temperature re-clamp
• Driver exit warning
• Dynamic apply
• Roll away re-clamp

Signals from other vehicle systems for operation of the EPB are transmitted to the ABS control module on the High Speed (HS) Controller Area Network (CAN) chassis systems bus and the HS CAN powertrain systems bus.

DESCRIPTION

Electric park brake switch

1. Release park brake
2. Apply park brake

The resistive ladder type switch has four hardwired connections with the ABS control module, consisting of two apply circuits and two release circuits. This enables the ABS control module to perform a plausibility check on each switch selection.

The park brake is manually applied and released using the EPB switch, which is located in the floor console, behind the selector lever. Pulling the switch lever upwards applies the park brake. Pushing the switch lever down releases the park brake.

ELECTRIC PARK BRAKE ACTUATORS

1. Brake caliper
2. Spindle
3. Seal
4. EPB actuator
5. Screws
6. Output shaft

The EPB actuators are electro-mechanical positioning units attached to the calipers of the rear brakes. Each actuator incorporates a reversible Electric motor driving an output shaft via a worm drive gear.

The output shaft of the EPB actuator is engaged in the splined end of a spindle, which is inside the caliper piston and screwed into a ball screw drive. Operation of the Electric motor turns the spindle and produces linear movement of the ball screw drive, to apply a target clamp load to the brake pads.

• Clutch Pedal Position Sensor (Manual Ransmission Vehicles Only)
• Parking Brake and Actuation - Operation

Parking Brake and Actuation Parking Brake Release Actuator (G1785118) / Removal and InstallationClutch Pedal Position Sensor (Manual Ransmission Vehicles Only)

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