LAND ROVER DISCOVERY 1999 Workshop Manual

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
DESCRIPTION AND OPERATION 54-3
Wheel hub
Section through wheel hub
1Drive shaft
2Axle casing
3Gaiter
4Upper ball joint
5Constant velocity joint
6Steering knuckle
7Hub bearing
8Hub flange9Wheel stud
10Stake nut
11ABS sensor ring
12Tension collet
13Lower ball joint
14Securing bands
15Shield
16Oil seal
Each wheel hub consists of a hub flange pressed into a hub bearing.
The hub flange is splined to accept the constant velocity joint of the drive shaft, which is secured to the hub flange
with a stake nut. Five studs are installed in the hub flange for the wheel nuts and a threaded hole is provided for the
brake disc securing screw.
The outer race of the hub bearing is bolted to the steering knuckle. The hub bearing is a sealed unit which contains
twin opposed roller bearings, pre-packed with grease during manufacture. A toothed ABS sensor ring is integrated
into the inner race of the hub bearing. An opening in the outer race of the hub bearing accommodates the ABS sensor.
Drive shaft
Each drive shaft consists of a solid rod, splined at both ends, with a constant velocity joint installed on the outboard
end. A shield is incorporated onto each rod to protect the oil seals in the axle casing. The constant velocity joint is of
the ball and socket type. A shaft on the constant velocity joint is splined to the hub flange. The constant velocity joint
is pre-packed with grease and protected by a gaiter. Two securing bands retain the gaiter in position.

FRONT AXLE
REPAIRS 54-5
REPAIRS
Differential - assembly
$% 54.10.01
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 front road wheels.
3.Drain oil from differential.

+ MAINTENANCE, PROCEDURES,
Front and rear axle.
4.If same components to be refitted, reference
mark propeller shaft and mating components.
5.Remove 4 nuts and bolts securing propeller
shaft to differential. Release propeller shaft and
tie aside.
6.Remove LH and RH front brake discs.

+ BRAKES, REPAIRS, Brake disc -
front.7.Disconnect each ABS sensor multiplug.
8.Release each harness from brake hose and
hose bracket.

FRONT AXLE
54-6 REPAIRS
9.Remove 4 bolts securing each front wheel hub
to front axle.
10.Release wheel hubs from front axle. Remove
wheel hubs and drive shafts from front axle.
11.Remove oil seal from axle casing.
12.Remove 10 bolts securing differential to axle
casing. Release and remove differential from
axle casing.Refit
1.Clean drive shaft oil seal recess, oil seal
running surface, wheel hub and axle mating
faces.
2.Using a suitable solvent, remove all traces
sealant from differential and axle mating faces.
3.Applysealant, Part No. STC 3811 to differential
or axle mating face.
4.Apply sealant, Part No. STC 50552 to threads
of differential securing bolts.
5.Fit differential to axle, fit bolts and tighten to 55
Nm (41 lbf.ft).
6.Position propeller shaft and align reference
marks. Fit bolts and tighten to 47 Nm (35 lbf.ft).
7.Lubricate oil seal lip and running surface with
clean differential oil.
+ CAPACITIES, FLUIDS,
LUBRICANTS AND SEALANTS,
Lubrication.
8.Using LRT-54-012 and LRT-99-003, fit new
drive shaft oil seal to axle casing.
9.Apply anti-seize compound to wheel hub and
steering knuckle mating faces.
10.Ensure ABS harnesses are located in cut out in
steering knuckles.
11.Fit drive shafts in axle casing and align wheel
hubs with steering knuckles. Fit wheel hub bolts
and tighten to 100 Nm (74 lbf.ft).
12.Connect each ABS sensor multiplug and
secure harness to harness bracket and brake
hose.

FRONT AXLE
REPAIRS 54-7
13.Fit front brake discs.

+ BRAKES, REPAIRS, Brake disc -
front.
14.Fit front road wheels and tighten nuts to 140
Nm (103 lbf.ft).
15.Remove stand(s) and lower vehicle.
16.Fill differential with oil.

+ MAINTENANCE, PROCEDURES,
Front and rear axle.
Seal - differential pinion
$% 54.10.20
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.Reference mark front propeller shaft for
reassembly.
3.Remove 4 nuts and bolts securing propeller
shaft to differential. Release propeller shaft and
tie aside.
4.Using LRT-51-003 to restrain pinion flange,
remove bolt and washer securing pinion flange.
Remove pinion flange.
5.Position container to catch oil spillage.

FRONT AXLE
54-8 REPAIRS
6.Using a suitable lever, remove pinion oil seal.
Take care to avoid damage to oil seal
recess.Refit
1.Clean pinion oil seal recess and pinion flange.
2.Lubricate pinion oil seal lip with clean
differential oil.

+ CAPACITIES, FLUIDS,
LUBRICANTS AND SEALANTS,
Lubrication.
3.Using LRT-51-010 , fit pinion oil seal.
4.Fit pinion flange and securing bolt and washer.
Using LRT- 51-003, restrain pinion flange and
tighten pinion flange bolt to 100 Nm (74 lbf.ft).
5.Position propeller shaft and align reference
marks. Fit nuts and bolts and tighten to 47 Nm
(35 lbf.ft).
6.Remove stand(s) and lower vehicle.
7.Check differential oil level.

+ MAINTENANCE, PROCEDURES,
Front and rear axle.

FRONT AXLE
REPAIRS 54-9
Seal - oil - front axle casing
$% 54.15.04
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 front brake disc.

+ BRAKES, REPAIRS, Brake disc -
front.
4.Disconnect ABS sensor multiplug.5.Release harness from brake hose and hose
bracket.
6.Remove 4 bolts securing wheel hub to steering
knuckle.
7.Release wheel hub from steering knuckle.
8.Remove wheel hub and drive shaft from axle.

FRONT AXLE
54-10 REPAIRS
9.Remove oil seal from axle casing.Refit
1.Clean drive shaft oil seal recess, oil seal
running surface, wheel hub and swivel hub
mating faces.
2.Lubricate oil seal lip and running surface with
clean differential oil.

+ CAPACITIES, FLUIDS,
LUBRICANTS AND SEALANTS,
Lubrication.
3.Using tool LRT-54-012 and tool LRT-99-003,
fit new drive shaft oil seal to axle casing.
4.Apply anti-seize compound to wheel hub and
steering knuckle mating faces.
5.Ensure ABS harness is located in cut out in
steering knuckle.
6.Fit drive shaft and wheel hub to axle casing and
align wheel hub with steering knuckle. Fit wheel
hub bolts and tighten to 100 Nm (74 lbf.ft).
7.Connect ABS sensor multiplug and secure
harness to harness bracket and brake hose.
8.Fit front brake disc.

+ BRAKES, REPAIRS, Brake disc -
front.
9.Fit road wheel and tighten nuts to 140 Nm (103
lbf.ft).
10.Remove stand(s) and lower vehicle.
11.Check differential oil level.

+ MAINTENANCE, PROCEDURES,
Front and rear axle.

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.