1999 LAND ROVER DISCOVERY suspension

FRONT AXLE
54-2 DESCRIPTION AND OPERATION
Description
General
The front axle consists of an axle casing with a differential unit attached to the right of the vehicle centre line. A wheel
hub is installed in a steering knuckle at each end of the axle casing and connected to the differential unit by a drive
shaft.
Axle casing
The axle casing is of welded construction, with brackets on the casing exterior for attachment to the front suspension.
Yokes at each end of the casing incorporate upper and lower ball joints for attachment of the steering knuckles.
A differential cover on the front of the axle casing contains an oil level plug for checking and replenishment of the
differential lubricating oil. A magnetic drain plug is installed on the underside of the casing. An oil seal is installed in
each end of the axle casing to prevent leakage past the drive shafts.
The interior of the axle casing is ventilated through a breather tube inserted in a red plastic sleeve in the top of the
casing. The open end of the breather tube is located in the left rear corner of the engine compartment.
Differential unit
The differential unit is of the spiral bevel type, lubricated by splash oil. The unit consists of a differential carrier
attached to a pinion housing. In the pinion housing, the pinion is splined to a drive flange which is secured with a bolt
and washer. An oil seal prevents leakage past the drive flange.
Steering knuckle
The steering knuckles are mounted on upper and lower ball joints in the yokes at the end of the axle casing. A tension
collet, in the lower mounting point of each steering knuckle, accommodates manufacturing tolerances to enable the
correct tightening of both ball joints. Lugs are incorporated on the steering knuckles for attachment of the steering
system drag link and track rod.

FRONT AXLE
REPAIRS 54-11
Constant velocity joint - drive shaft
$% 54.20.21
Remove
1.Remove wheel hub.

+ FRONT SUSPENSION, REPAIRS,
Wheel hub.
2.Place drive shaft in vice.
3.Release both securing bands from gaiter and
discard.
4.Compress gaiter to gain access to joint.
5.Using a suitable drift against the inner part of
the joint, remove joint from shaft.
6.Remove circlip from shaft and discard.
7.Remove spacer from shaft.
8.Remove gaiter from shaft and inspect for
damage. Renew if necessary. Refit
1.Clean drive shaft and gaiter.
2.Clean spacer.
3.Fit new inner securing band to gaiter.
4.Fit gaiter to shaft.
5.Fit spacer to shaft.
6.Fit new circlip to shaft.
7.Position joint to shaft. Use a screwdriver to
press circlip into its groove and push joint fully
onto shaft.
8.Apply grease from the sachet to the joint.
9.Position gaiter to joint and fit new outer
securing band.
10.Use a Band-it thriftool to secure inner and outer
securing bands.
11.Fit wheel hub.

+ FRONT SUSPENSION, REPAIRS,
Wheel hub.

STEERING
ADJUSTMENTS 57-19
5.Adjust drag link so that taper joint is centralised
in drop arm, then tighten drag link clamp bolts:
Tighten M8 bolts to 22 Nm (16 lbf.ft) and M10
bolts to 33 Nm (24 lbf.ft).
6.Connect drag link to drop arm and tighten nut to
80 Nm (59 lbf.ft).
7.Remove steering box centralising bolt.
8.Remove stand(s) and lower vehicle.
9.Road test the vehicle and check that the
steering wheel is centralised. If steering wheel
is not centralised, proceed as follows.
10.Slacken drag link adjuster clamp bolts.
11.Without disconnecting drag link from drop arm,
adjust the length of the drag link to bring the
steering wheel to the central position.
CAUTION: Repositioning the steering wheel
on its splines cannot correct small (less
than 5°) errors in steering wheel alignment.
Always rectify small errors in alignment by
adjusting the drag link as detailed above,
ensuring that steering box centralisation is
maintained.
12.Tighten drag link clamp bolts: Tighten M8 bolts
to 22 Nm (16 lbf.ft) and M10 bolts to 33 Nm (24
lbf.ft)
Wheel alignment - front
$% 57.65.01
The following is the only wheel alignment equipment
which has been approved.
lBeissbarth ML 4600 wheel alignment computer
(6 sensor).
lBeissbarth ML 4600-8 wheel alignment
computer (8 sensor).
lBeissbarth ML 4000 wheel alignment computer
(8 sensor wireless).
lHunter S411-14.
Check
1.Ensure tyre pressures are correct and vehicle
is at kerbside weight.
2.Roll vehicle backwards and forwards to relieve
stresses in steering and suspension.
3.Ensure road wheels are positioned straight
ahead.
4.Ensure that wheel alignment equipment is
properly calibrated.
5.Following the equipment manufacturer's
instructions, measure the front wheel
alignment. Compare with the figures given in
General Data.

+ GENERAL DATA, Steering.
Adjust
1.Loosen track rod and adjuster clamp bolts.
2.Rotate adjuster to obtain correct alignment.

+ GENERAL DATA, Steering.
3.Tighten track rod and adjuster clamp bolts:
Tighten M8 bolts to 22 Nm (16 lbf.ft) and M10
bolts to 33 Nm (24 lbf.ft).
4.Recheck front wheel alignment.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-1
FRONT SUSPENSION DESCRIPTION AND OPERAT ION
Front suspension component layout
(ACE torsion bar shown)
1Turret RH
2Radius arm LH
3Anti-roll bar link LH
4Damper LH
5Turret LH
6Coil spring LH
7Torsion/anti-roll bar
8Steering knuckle
9Steering damper
10Drag link
11ACE short arm (if fitted)12Panhard rod
13ACE long arm (if fitted)
14Steering knuckle
15Brake caliper and hub assembly
16Radius arm RH
17Coil spring RH
18ACE actuator
19Anti-roll bar link RH
20ACE actuator
21Anti-roll bar link RH

FRONT SUSPENSION
60-2 DESCRIPTION AND OPERATION
Front suspension components (ACE
torsion bar shown)

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-3
1Damper 2 off
2Bolt 2 off
3Turret 2 off
4Nut 8 off
5Nut
6Bolt 4 off
7Nut
8Washer
9Anti-roll bar link RH
10Torsion/Anti-roll bar assembly
11Anti-roll bar link LH
12Washer
13Nut
14Nut
15Mounting rubber 2 off
16Clamp plate 2 off
17Bolt 2 off
18Lower spring seat LH
19Front axle20Nut
21Bush
22Panhard rod
23Bolt
24Radius arm LH
25Bolt
26Bush
27Nut
28Nut
29Bush
30Bolt
31Radius arm RH
32Bolt
33Bush
34Nut
35Lower spring seat RH
36Coil spring 2 off
37Upper spring seat 2 off

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
DESCRIPTION AND OPERATION 60-5
Coil springs
Coil springs are fitted to the front axle of the vehicle. The front springs differ between petrol and Diesel variants. Each
spring is retained at its base by the lower spring seat. The top of each spring is located in the upper spring seat
isolator. The upper spring seat is manufactured from natural rubber , with a bonded metal plate and four bonded studs
which provide for the attachment of the damper turret. The rubber isolator reduces noise transmitted to the chassis
and body from the suspension.
The coil springs must be installed correctly. The bottom coil of the spring locates in a recess in the lower spring seat.
The top coil of the spring is ground flat to locate the upper spring seat isolator.
Coil Spring Specifications – Models up to 03 Model Year
The front springs on petrol variants are manufactured from carbon chrome 13.9 mm (0.55 in) diameter bar. The spring
has 7.6 coils and a free length of 377 mm (14.8 in). The petrol front spring is identified by a pink and orange stripe
painted on a number of coils.
The front springs on Diesel variants are manufactured from carbon chrome 13.9 mm (0.55 in) diameter bar. The spring
has 7.6 coils and a free length of 383 mm (15.0 in). The Diesel front spring is identified by a white and purple stripe
painted on a number of coils.
Coil Spring Specifications – Models from 03 Model Year
The introduction of the 03MY vehicle introduced a range of additional spring fitments. These were introduced to cover
the introduction of the 4.6l V8 engine, the fitment of a front mounted winch and to optimise the vehicle trim heights.
The coil springs are manufactured from silicon manganese 13.8 mm or 13.9 mm (0.54 in or 0.55 in) diameter bar. The
following spring data table shows the colour codes, number of coils and spring free length.
Spring Data
The following table shows spring fitment applicablity.
Spring Fitment Applicability
The following table shows standard springs and uprated springs required when a front winch is fitted.
Winch Fitment Spring Applicability
Colour Code Total No. of Coils Free Length
Red/Purple 7.4 371 mm (14.6 in)
Yellow/Purple 7.4 378.4 mm (14.9 in)
Blue/Purple 7.4 365 mm (14.4 in)
Grey/Purple 7.4 387 mm (15.2 in)
Purple/Purple 7.4 373.8 mm (14.7 in)
Yellow/Orange 7.4 394.6 mm (15.5 in)
Green/Orange 7.4 382.6 mm (15 in)
Pink/Brown 7.6 405.6 mm (15.9 in)
Left Hand Drive Right Hand Drive
RH side LH side RH side LH side
Red/Purple Red/Purple Yellow/Purple Blue/Purple
Yellow/Purple Yellow/Purple Grey/Purple Purple/Purple
Grey/Purple Grey/Purple Yellow/Orange Green/Orange
Standard Spring Winch Fitted Spring
RH Side LH Side Both Sides
Red/Purple Red/Purple Grey/Purple
Yellow/Purple Blue/Purple Yellow/Orange
Yellow/Purple Yellow/Purple Yellow/Orange
Grey/Purple Purple/Purple Green/Orange
Grey/Purple Grey/Purple Green/Orange
Yellow/Orange Green/Orange Pink/Brown