wheel LAND ROVER DISCOVERY 1999 Workshop Manual

FRONT SUSPENSION
60-4 DESCRIPTION AND OPERATION
Description
General
The front suspension comprises two dampers and coil springs, two radius arms, a Panhard rod and an anti-roll bar.
The front axle provides the location points for the dampers, springs, radius arms and the Panhard rod.
The anti-roll bar assembly is an essential part of the front suspension. On vehicles without Active Cornering
Enhancement (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 coil springs provide springing for each front wheel. The long travel dampers, springs and
radius arms provide maximum axle articulation and wheel travel for off-road driving. The front axle is controlled
longitudinally by two forged steel radius arms and transversely by a Panhard rod.
Radius arms
Each radius arm is manufactured from forged steel. Two bushes are pressed into the forward end of the radius arm.
The forward end of the radius arm is located in a fabricated bracket on the axle and secured through the bushes with
two bolts and nuts. A bush is pressed into the rear of the radius arm which is also located in a fabricated bracket on
each chassis longitudinal and secured through the bush with a bolt and nut.
The radius arms prevent longitudinal movement of the front 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. A turret is located on a bracket welded
to the chassis. The upper spring seat has four studs which pass through holes in the bracket and align with
corresponding holes in the turret. Four nuts are screwed onto the studs and secure the turret and upper spring seat
to the chassis.
A fabricated platform is welded to the axle. The platform has two captive nuts which provide for the attachment of the
damper. A lower spring seat is located on the platform. Each spring seat is handed and has a bracket which secures
the ABS sensor harness and the front brake hose.
Each damper is fitted with a bush at its upper end. The bush locates in the top of the turret and is secured with a cross
bolt. The lower attachment point for the damper is also fitted with a bush. This bush has a spindle through its centre
with a hole at each end. The spindle is seated on the lower spring seat and the axle platform and secured with two
bolts. The coil spring is fitted in a compressed state between the upper and lower spring seats and assists the damper
in controlling the body/axle movement. The upper and lower bushes are replaceable items.
Rubber bump stops are fitted to the chassis above each end of the axle. The bump stops are progressive in their
compression and prevent the axle from contacting the chassis in the event of maximum suspension travel being
reached. The bump stops revert to their original shape once the compression load has been removed from them.
The damper functions by restricting the flow of a hydraulic fluid through internal galleries within the damper body. A
chromium plated rod moves axially within the damper. As the rod moves, its movement is limited by the flow of fluid
through the galleries thus providing damping of undulations in the terrain. The damper rod is sealed at its exit point
from the body to maintain fluid within the unit and prevent the ingress of dirt and moisture. The seal also acts as a
wiper to keep the rod outer diameter clean. A plastic shroud protects the rod and slides over the body as the damper
moves. The coil spring aids the damper to extend after being compressed and also aids the damping process.

FRONT SUSPENSION
60-30 REPAIRS
Refit
1.Clean lower ball joint location and surrounding
area of axle yoke.
2.Apply a 12 mm (0.5 in) wide yellow paint stripe
on axle yoke, adjacent to lower ball joint
location.
3.Fit tool LRT-54-022 to tool LRT-54-008 and
secure with screw.
4.Fit tool LRT-54-022 and tool LRT-54-008 to
lower ball joint location on axle yoke.
5.Fit new lower ball joint to tool LRT-54-008/14.
6.Fit LRT-54-008/14 and lower ball joint to LRT-
54-008, with lower ball joint positioned on axle
yoke.
7.Align tool assembly and press lower ball joint
into axle yoke.
CAUTION: Damage to the joint boot will
result if the tool is not correctly aligned
during the fitting procedure.
8.Remove tools from axle yoke
9.Fit steering knuckle.

+ FRONT SUSPENSION, REPAIRS,
Steering knuckle.
Steering knuckle
$% 60.15.19
Remove
1.Remove wheel hub.

+ FRONT SUSPENSION, REPAIRS,
Wheel hub.
2.Remove 3 bolts securing mudshield and
remove mudshield.
3.Remove 2 nuts securing track rod and (if
applicable) drag link to steering knuckle.
4.Break taper joints using LRT-57-036, then
position track rod and drag link aside.

FRONT SUSPENSION
REPAIRS 60-31
5.Remove 2 nuts securing ball joints to steering
knuckle.
6.Break taper joints using LRT-54-027 and
remove steering knuckle.
7.Remove tension collet from steering knuckle.
8.Remove drive shaft oil seal from axle casing.Refit
1.Clean taper bores in steering knuckle and
tension collet.
2.Fit tension collet into steering knuckle and
tighten to 5 Nm (3.7 lbf.ft).
3.Clean ball joint tapers and taper seats.
4.Position steering knuckle to axle yoke. Fit
upper ball joint nut and tighten to 110 Nm (81
lbf.ft). Fit lower ball joint nut and tighten to 135
Nm (100 lbf.ft).
5.Clean track rod and (if applicable) drag link
tapers and taper seats.
6.Connect track rod and drag link to steering
knuckle. Fit track rod and drag link nuts and
tighten to 80 Nm (59 lbf.ft).
7.Clean mudshield and steering knuckle mating
faces. Position mudshield, fit bolts and tighten
to 10 Nm (7 lbf.ft).
8.Fit wheel hub.
+ FRONT SUSPENSION, REPAIRS,
Wheel hub.

FRONT SUSPENSION
60-32 REPAIRS
Road spring - front
$% 60.20.11
Remove
1.Raise front 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 front road wheels.
4.Support weight of front axle.
5.Remove 2 nuts securing anti-roll bar links to
front axle and disconnect links from axle.
6.Remove 2 bolts securing each damper to front
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.
7.Lower front axle.
CAUTION: Ensure brake hoses and ABS
sensor harnesses are not damaged when
lowering front axle.
8.Release and remove front spring from damper.Refit
1.Clean front spring seats.
2.Position front spring, with close coil uppermost,
over damper and locate in cut out in lower
spring seat.
3.Ensure both front springs are correctly located
in spring seats and raise front axle. Fit bolts
securing both dampers to front axle and tighten
to 45 Nm (33 lbf.ft).
4.Ensure washer is in place on lower ball joint of
each anti-roll bar link, then connect lower ball
joints to axle. Tighten nuts to 100 Nm (74 lbf.ft).
5.Fit front road wheels and tighten nuts to 140
Nm (103 lbf.ft).
6.Remove stands and lower vehicle.

FRONT SUSPENSION
REPAIRS 60-33
Wheel hub
$% 60.25.01
Remove
1.Release ABS sensor harness grommet from
inner wing valance and disconnect multiplug.
2.Raise front of vehicle.
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.Pull ABS sensor harness through aperture into
wheel arch.5.Release harness from brackets on inner wing
valance, suspension turret and front hub.
6.Release stake from drive shaft nut.
7.With assistance, remove drive shaft nut.
Discard the nut.
8.Remove front brake disc.

+ BRAKES, REPAIRS, Brake disc -
front.
9.Remove 4 bolts securing wheel hub to steering
knuckle.
10.Release wheel hub from steering knuckle, then
remove wheel hub and drive shaft assembly
from axle.
CAUTION: Do NOT remove the ABS sensor
from the hub. The hub and the sensor are
supplied as an assembly.

FRONT SUSPENSION
60-34 REPAIRS
11.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.
12.Remove drive shaft oil seal from axle casing. Refit
1.Clean drive shaft oil seal recess, drive shaft
splines, oil seal running surface, wheel hub
and steering knuckle mating faces, ABS
sensor and sensor recess.
2.Lubricate lip of new drive shaft oil seal and
running surface on drive shaft with clean
differential oil.

+ CAPACITIES, FLUIDS,
LUBRICANTS AND SEALANTS,
Lubrication.
3.Use tool LRT-51-012 to fit new drive shaft oil
seal to axle casing.
4.Fit drive shaft to axle casing.
5.Apply anti-seize compound to wheel hub and
steering knuckle mating face.
M51 0057

FRONT SUSPENSION
REPAIRS 60-35
6.Apply a 3 mm (0.125 in) wide bead of sealant,
Part No. STC 50554 around drive shaft
circumference, as illustrated.
7.Ensure ABS harness is located in cut out in
steering knuckle.
8.Fit wheel hub to drive shaft and align steering
knuckle. The sealant will smear along the
length of the splines as the wheel hub is fitted
to the drive shaft.
9.Fit wheel hub bolts and tighten to 100 Nm (74
lbf.ft).
10.Fit new drive shaft nut and lightly tighten.
11.Fit front brake disc.

+ BRAKES, REPAIRS, Brake disc -
front.
12.With assistance, final tighten drive shaft nut to
490 Nm (360 lbf.ft). Stake drive shaft nut. The
drive shaft nut must be tightened before
sealant has cured.
13.Secure ABS sensor harness to brackets and
secure grommet to inner wing.
14.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
15.Remove stand(s) and lower vehicle.
16.Connect ABS sensor multiplug.
Damper - front
$% 60.30.02
Remove
1.Raise front 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. RH damper: Release coolant reservoir and
position aside.
4.Loosen through bolt securing damper to turret.
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.
M51 0058

FRONT SUSPENSION
60-36 REPAIRS
5.Remove 4 nuts securing turret base to chassis.
6.Remove 2 bolts securing damper to axle.
7. ACE models: Remove bolt securing ACE pipe
clamp to chassis.
8. ACE models: Remove bolt securing ACE pipe
clamp to turret.
9.Release harness clip from turret.
10.Raise turret and remove through bolt.
11.Compress damper and manoeuvre turret from
engine bay.
12.Remove damper. Refit
1.Position damper and manoeuvre turret into
position. Raise damper and align to turret. Fit
through bolt but do not tighten at this stage.
2.Align damper assembly to spring seat.
3.Fit bolts securing damper to axle and tighten to
45 Nm (33 lbf.ft).
4.Fit nuts securing turret to chassis and tighten
to 23 Nm (17 lbf.ft).
5.Tighten through bolt to 125 Nm (92 lbf.ft).
6. ACE models: Position ACE pipe clamp to
chassis and secure with bolt.
7. ACE models: Position ACE pipe clamp to
turret and secure with bolt.
8.Secure harness to turret.
9. RH damper: Reposition coolant reservoir.
10.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
11.Remove stand(s) and lower vehicle.

FRONT SUSPENSION
REPAIRS 60-37
Bushes - radius arm
$% 60.35.18
Remove
1.Raise front 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.Remove and discard nut securing track rod to
steering knuckle.
4.Using LRT-57-036 break taper, release track
rod and position aside5.Remove and discard cable tie securing front
axle breather
6.Remove nut and bolt securing radius arm to
chassis.
7.Remove 2 nuts securing radius arm to axle.
8.Remove rear bolt from radius arm.
9.Remove front bolt from radius arm and remove
radius arm from axle.

FRONT SUSPENSION
60-38 REPAIRS
10.Using LRT-60-011/1 and LRT-60-011/2 press
out bush from rear end of radius arm.
11.Using a suitable piece of tubing, press out
bushes from axle end of radius arm.Refit
1.Clean and lubricate bush and radius arm
mating faces.
2.Using LRT-60-011/1,LRT-60-011/2 and LRT-
60-011/3, press bush into rear end of radius
arm.
3.Using a suitable piece of tubing press front
radius arm bush into radius arm.
4.Repeat above operation for remaining bush.
5.Position radius arm to vehicle and fit securing
nuts and bolts, do not tighten at this stage.
CAUTION: Nuts and bolts must be tightened
with weight of vehicle on suspension.
6.Fit cable tie to secure axle breather.
7.Fit track rod to steering knuckle and secure with
nut, tighten to 125 Nm (92 lbf.ft).
8.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
9.Remove stand(s) and lower vehicle.
10.Tighten radius arm nuts and bolts to 230 Nm
(170 lbf.ft).