wheel LAND ROVER DISCOVERY 2002 Workshop Manual

REAR SUSPENSION
64-6 DESCRIPTION AND OPERATION
Description
General
The rear suspension comprises two dampers, two radius arms, a Watts linkage and an anti-roll bar assembly. On
vehicles without Self Levelling Suspension (SLS) coil springs are used. On vehicles with SLS air springs are used.
The anti-roll bar is an essential part of the rear suspension. On vehicles without ACE, a conventional 'passive' anti-
roll bar is fitted. On vehicles fitted with the ACE system, a thicker diameter anti-roll bar, known as a torsion bar, is used
with an actuator at one end.

+ FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE.
The hydraulic dampers and springs provide springing for each rear wheel. The long travel dampers, springs and
radius arms provide maximum axle articulation and wheel travel for off-road driving. The rear axle is controlled
longitudinally by two forged steel radius arms and transversely by a Watts linkage.
Radius arms
Each radius arm is manufactured from forged steel. Two bushes are pressed into the rear of the radius arm. The rear
of the radius arm is located between a fabricated bracket on the axle and secured through the bushes with two bolts
and nuts. A bush is pressed into the forward end of the radius arm which is located in a fabricated bracket on each
chassis longitudinal and secured through the bush with a bolt and nut. Each radius arm is similar in its construction
to the front radius arms. The rear radius arms are shorter than the front and have a lug for attachment of the SLS
height sensor (when fitted).
The radius arms prevent longitudinal movement of the rear axle and because of their length allow maximum axle
articulation. The stiffness of the bushes in each radius arm also contributes to the vehicle roll stiffness.
Each radius arm has a notch on its lower edge which provides location for the vehicle jack.
Dampers
Two conventional telescopic dampers are used to control body/axle movement. The upper damper mounting is fitted
with a bush which locates in a bracket on the chassis longitudinal. The damper is secured with a bolt which screws
into a captive nut on the bracket. The lower damper mounting is also fitted with a bush and locates in a fabricated
bracket attached to the rear axle. The lower mounting is secured with a bolt which screws into a captive nut on the
bracket. The upper and lower bushes are replaceable items.
Air springs (vehicles with SLS)
On vehicles with SLS fitted, air springs are fitted between the rear axle and the chassis. Each spring is located at its
base on a fabricated platform on the rear axle. The top of the spring locates in a fabricated bracket attached to the
outside of each chassis longitudinal.
The plastic base of the air spring has two lugs which locate in a slotted hole in the rear axle platform. The spring is
secured by rotating the spring through 90
°, locating the lug in the platform. The plastic top of the air spring has two
grooved pins which locate in holes in the bracket on the chassis. Two spring clips locate on the grooved pins and
retain the top of the spring in position.
Each air spring comprises a top plate assembly, an air bag and a base piston. The air bag is attached to the top plate
and the piston with a crimped ring. The air bag is made from a flexible rubber material which allows the bag to expand
with air pressure and deform under load. The top plate assembly comprises the plastic top plate with two bonded
grooved pins on its top face. In the centre of the top face is a female connector which allows for the attachment of the
air hose from the SLS compressor. The piston is made from plastic and is shaped to allow the air bag to roll over its
outer diameter. The base of the piston is recessed with a boss moulded in the centre. The boss has two lugs which
provide attachment to the axle platform.

REAR SUSPENSION
DESCRIPTION AND OPERATION 64-21
Normal ride height
When the vehicle is stationary, a door is open and the ignition is off, the SLS system will allow the rear of the vehicle
to lower to within 20 mm of the normal ride height as load is removed from the vehicle. The SLS system will only
operate the compressor to raise the rear of the vehicle when the engine is running, unless requested using the remote
handset.
Off-road mode (ORM)
ORM is used to raise the rear of the vehicle from normal ride height to the ORM ride height of 100 mm between the
tip of the bump stop and the axle.
ORM is activated by depressing the ORM switch located on the fascia for not less than 0.5 seconds. With the engine
running, all doors closed and the vehicle speed below 18 mph (30 km/h), the audible warning will sound once and the
ORM warning lamp in the instrument pack will start to flash when the switch is released. The compressor will be
started and the air control valves will be energised by the ECU to inflate the air springs and raise the rear of the vehicle.
When the full ORM height is reached, the ECU will terminate compressor operation and close the air valves. The ORM
warning lamp will stop flashing and remain continuously illuminated to inform the driver that the SLS system is in ORM.
When ORM is no longer required, depressing the ORM switch for not less than 0.5 seconds with all doors closed will
lower the SLS to normal ride height. The audible warning will sound once and the ORM warning lamp will flash as the
suspension lowers. The ECU energises the air control valves and the exhaust valve to release air pressure from the
air springs. When standard ride height is reached the ORM warning lamp will extinguish and the ECU will de-energise
the air control valves and the exhaust valve solenoids.
If the SLS is in ORM and the vehicle speed exceeds 18 mph (30 km/h), the ECU will lower the SLS to standard ride
height. The driver will be informed of this by an audible warning and the ORM warning lamp flashing as the suspension
lowers. When normal ride height is achieved, the ORM warning lamp will extinguish.
At sea level, the time to change the SLS from normal ride height to ORM or visa versa will take between 15 and 20
seconds.
If the ECU determines that conditions are not correct for SLS operation, i.e.; axle articulation or system fault, the
audible warning will sound three times to inform the driver that the ORM request has not been granted.
Extended mode
The extended mode is automatically operated by the ECU and requires no input from the driver. Extended mode
operates when the chassis is grounded causing the rear wheels to spin. This information is generated by the ABS
function of the SLABS ECU.
When the ECU senses that the chassis is grounded and the vehicle speed is less than 6 mph (10 km/h), the ECU will
operate the compressor and energise the air control valves for 25 seconds to raise the rear of the vehicle. This
operates irrespective of the mode that the SLS system is in at that time. To inform the driver, the ORM warning lamp
will flash continuously at all times that the system is in extended mode.
The driver can exit the extended mode by depressing the ORM switch for not less than 0.5 seconds or by exceeding
8 mph (13 km/h).
Remote handset SLS control
The remote handset is an accessory item which allows the SLS to be operated between normal ride height and bump
stop height to allow easier connection and disconnection of trailers. The remote handset is similar in appearance to
that of the remote door locking handset but does not have an integral key. A circular button with an arrow is used to
raise the SLS and an oval button with the 'Land Rover' logo is used to lower the SLS.
The remote handset control requires all doors to be closed and the ignition to be in position II, but the engine does
not need to be running.

REAR SUSPENSION
REPAIRS 64-25
REPAIRS
Wheel hub
$% 64.15.01
Models with SLS:
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Remove road wheel.
3.Release stake in drive shaft nut.
4.With an assistant depressing the brake pedal,
remove and discard drive shaft nut.
5.Remove rear brake disc.

+ BRAKES, REPAIRS, Brake disc -
rear.6.Disconnect ABS sensor multiplug.
7.Release harness from brake hose and hose
bracket.
8.Remove 4 bolts securing wheel hub to axle.
9.Release and remove wheel hub and drive shaft
assembly from axle. Remove and discard 'O'
ring from wheel hub.

REAR SUSPENSION
64-26 REPAIRS
10.Position the wheel hub and drive shaft on a
press, place supports beneath the wheel studs
and press the drive shaft from the wheel hub.Refit
1.Clean drive shaft splines, wheel hub and axle
mating faces, ABS sensor and sensor recess.
2.Fit drive shaft to axle casing.
3.Lubricate new bearing hub 'O' ring with clean
differential oil.

+ CAPACITIES, FLUIDS AND
LUBRICANTS, Lubrication.
4.Fit 'O' ring to wheel hub.
5.Apply a 3 mm (0.125 in) wide bead of Loctite
640 around drive shaft circumference as
illustrated.
6.Fit wheel hub to drive shaft and align to axle.
The Loctite will smear along the length of the
splines as the wheel hub is fitted to the drive
shaft.
7.Fit bolts securing wheel hub to axle and tighten
to 100 Nm (74 lbf.ft).
8.Fit new drive shaft nut and lightly tighten.
9.Fit rear brake disc.

+ BRAKES, REPAIRS, Brake disc -
rear.
10.With an assistant depressing the brake pedal,
tighten drive shaft nut to 490 Nm (360 lbf.ft).
Stake drive shaft nut. The drive shaft nut
must be tightened before the Loctite has
cured.
11.Connect ABS sensor multiplug and secure
harness to harness bracket and brake hose.
12.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
13.Remove stand(s) and lower vehicle.
M51 0057
M51 0058

REAR SUSPENSION
REPAIRS 64-27
Road spring - rear
$% 64.20.01
Remove
1.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Support vehicle under chassis.
3.Remove road wheel.
4.Support weight of axle on a jack.
5.Remove bolt securing damper to axle.
WARNING: Make sure the axle cannot move
when the damper is disconnected. The
damper limits the downward movement of
the axle. If the axle is not restrained,
disconnecting the damper will allow
unrestricted movement which may cause
personal injury or damage to equipment.
6.Remove clip securing brake pipe to bracket. 7.Release ABS sensor lead from bracket.
8.Lower axle on jack and remove spring.
Refit
1.Ensure spring seats are clean.
2.Fit spring with close coil uppermost.
3.Ensure spring is correctly located on spring
seats and raise axle. Fit and tighten bolt
securing damper to axle to 124 Nm (91 lbf.ft).
4.Fit clip to secure brake pipe to bracket.
5.Fit ABS sensor lead to bracket.
6.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
7.Remove stand(s) and lower vehicle.

REAR SUSPENSION
64-28 REPAIRS
Air spring - SLS
$% 64.21.01
Remove
1.Using TestBook, depressurise SLS air system.
After depressurisation, approximately 1 bar
(15 lbf.in
2) air pressure remains in the
system.
2.Raise rear of vehicle and support under
chassis.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
3.Remove road wheel.
4.Remove 2 clips securing air spring to chassis.
5.Collapse air spring and disconnect pipe from
top of air spring.
CAUTION: Always fit plugs to open
connections to prevent contamination.
6.Rotate air spring, to unlock from axle and
remove from vehicle.
7.Remove connector from pipe.Refit
1.Clean mating faces of air spring, axle and
chassis.
2.Fit pipe connector to air spring.
3.Locate air spring on axle and rotate 90
° to fully
engage bayonet fitting.
4.Connect pipe to top of air spring.
5.Engage top locating pins of air spring in chassis
and secure with clips.
6.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
7.Remove stand(s) and lower vehicle.

REAR SUSPENSION
REPAIRS 64-29
Damper - rear
$% 64.30.02
Remove
1.Raise rear of vehicle and support under
chassis.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Remove road wheel.
3.Support weight of axle on a jack.
4.Remove 2 bolts securing damper to axle and
chassis.
WARNING: Make sure the axle cannot move
when the damper is disconnected. The
damper limits the downward movement of
the axle. If the axle is not restrained,
disconnecting the damper will allow
unrestricted movement which may cause
personal injury or damage to equipment.
5.Compress damper and remove from vehicle.
Refit
1.Locate damper in axle and fit lower bolt, extend
damper to chassis and fit top bolt.
2.Tighten damper bolts to 125 Nm (92 lbf.ft).
3.Lower axle and remove jack.
4.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
5.Remove stand(s) and lower vehicle.
Bushes - radius arm
$% 64.35.29
Models with SLS:
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Remove road wheel(s).
3. Models with SLS: Remove nut and bolt
securing height sensor link to radius arm.
4.Remove nut and bolt securing radius arm to
chassis.
5.Remove nuts securing radius arm to axle.
Remove rear bolt and lower radius arm.
Remove front bolt and remove radius arm.

REAR SUSPENSION
64-30 REPAIRS
6.Press out bushes from axle end of radius arm
using a length of steel tubing.
7.Press out bush from rear of radius arm:
lUse LRT-60-011/1 and LRT-60-011/2 to
remove rear bush.Refit
1.Clean bush locations in radius arms.
2.Press in new bushes:
lUse LRT-60-011/1, LRT-60-011/2 and
LRT-60-011/3 to fit rear bush.
3.Position radius arm to vehicle. Fit bolts and nuts
but do not tighten at this stage.
4. Models with SLS: Position height sensor link
to radius arm and tighten nut and bolt to 25 Nm
(18 lbf.ft).
5.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
6.Remove stand(s) and lower vehicle.
7.Tighten radius arm nuts and bolts to 230 Nm
(170 lbf.ft).
CAUTION: Nuts and bolts must be tightened
with weight of vehicle on suspension.
8.Use TestBook to calibrate SLS height sensor.

BRAKES
DESCRIPTION AND OPERATION 70-5
Description
General
The brakes consist of front and rear disc brakes operated by a diagonally split, dual circuit hydraulic system with
vacuum servo power assistance. The system incorporates the following control functions as standard on all models:
lAnti-lock Brakes (ABS), to prevent road wheels locking during brake application.
lElectronic Brake Distribution (EBD), to control distribution of hydraulic pressure between front and rear axles.
Replaces mechanical pressure limiting valve of previous systems.
lElectronic Traction Control (ETC), to maintain even torque distribution to the road wheels.
lHill Descent Control (HDC), to provide controlled descent ability in off road conditions.
Hydraulic system schematic
1Master cylinder/brake servo assembly
2Brake pedal
3ABS modulator
4Rear brake
5Front brake
6Hydraulic circuit
aPrimary
bSecondary
For normal brake operation, brake pedal movement is assisted by the brake servo assembly and transmitted to the
master cylinder assembly. The master cylinder assembly converts brake pedal movement to hydraulic pressure.
Primary and secondary brake pipe circuits supply the hydraulic pressure to the brakes via the ABS modulator: the
primary circuit supplies the front left and rear right brakes; the secondary circuit supplies the front right and rear left
brakes. Vacuum for the brake servo assembly is obtained from the engine inlet manifold (V8 models) or a vacuum
pump (diesel models), through a vacuum line and non return valve. To reduce operating noise, sleeving is installed
on some of the brake pipes in the engine compartment and the pipes are located in sprung pipe clips.

BRAKES
70-6 DESCRIPTION AND OPERATION
For all control functions, the ABS modulator regulates the hydraulic pressure to the brakes to control the speed of all
four wheels, either individually or in axle pairs. Operation of the ABS modulator is controlled by the Self Levelling and
Anti-lock Braking Systems (SLABS) ECU. The SLABS ECU also operates warning indications in the instrument pack
to provide the driver with status information on each function.
Brake servo assembly
The brake servo assembly provides power assistance to reduce the pedal load when braking. If the brake servo
assembly fails, the hydraulic system still functions but will require greater brake pedal effort due to the lack of vacuum
assistance.
Two integral tie bolts attach the brake servo assembly to the pedal and bracket assembly on the engine bulkhead.
The master cylinder assembly is attached to the forward ends of the tie bolts.
The brake servo assembly consists of a circular housing which contains two diaphragms, a central plate, a control
valve assembly, input and output push rods and a filter. The input push rod is connected to the brake pedal. The output
push rod locates in the primary piston of the master cylinder. A protective gaiter is installed on the control valve
assembly where it extends from the rear of the housing. A non return valve, installed in a port in the front face of the
housing, is connected to a vacuum line from the engine.
The control valve assembly consists of a valve body containing a valve, a piston, a valve spring and an input rod
spring. The valve controls a vacuum port in the valve body. The piston controls an air inlet port between the valve and
the piston. A reaction disc and a ratio disc separate the piston from the output push rod. A guide tube on the front of
the valve body is attached to the front diaphragm and supported in a bush in the central plate. A return spring locates
in the open end of the guide tube.
The two diaphragms and the central plate separate the interior of the housing into four sealed chambers. The
chambers at the front of the diaphragms are connected together through fixed passages in the valve assembly. The
chambers at the rear of the diaphragms are connected together through the interior of minor diaphragms on the tie
bolts.
Brakes off
With the brake pedal released, the piston in the control valve assembly positions the valve so that the vacuum port is
open and the two pairs of chambers are connected together. When the engine is running air is evacuated through the
vacuum line and non return valve, creating a partial vacuum in all four chambers. When the engine stops, the non
return valve closes to maintain the partial vacuum and, on V8 models, prevent fuel vapour entering the brake servo.