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
- Integrated Anti-lock Brake System (ABS) control module and Hydraulic
Control
Unit (HCU)
- Instrument Cluster (IC)
- Right Electric Park Brake (EPB) actuator
- Left EPB actuator
- 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
- Release park brake
- 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
- Brake caliper
- Spindle
- Seal
- EPB actuator
- Screws
- 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.
READ NEXT:
The clutch pedal position sensor provides the ABS control module with a
continuous measure of clutch pedal position.
The clutch pedal position sensor is attached to the clutch master cylinder.
The
Operation
When the park brake is applied with the EPB switch, the ABS control
module uses the wheel speed inputs to determine when to use the static
and dynamic modes of operation. It uses the static
PRINCIPLES OF OPERATION
For a detailed description of the Parking Brake, refer to the relevant
Description and Operation section in the workshop manual. REFER to:
Parking Brake (206-05 Parking Brake a
SEE MORE:
Installation
Torque: 24 Nm
NOTES:
Do not tighten at this stage.
This step requires the aid of another technician.
CAUTION:
The component must be aligned with the installation
markings.
NOTES:
Make sure that new bolts are installed.
Tighten the retaining bolts working diagonally.
Renew
Following cleaning of the vehicle's
exterior (particularly with a
pressure washer), it is
recommended that the vehicle is
taken for a short drive to dry out
the brakes
To prevent damage to your vehicle
when using a valeting service, make
sure to advise them of the cleaning
instructions containe