1999 LAND ROVER DISCOVERY lock

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-56 REPAIRS
Solenoids - shift control valves
(MV 1 & 2)
$% 44.15.45
Remove
1.Remove valve body assembly.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.
2.Remove 3 Torx screws securing lock-up
solenoid valve assembly to valve body and
move solenoid aside.
NOTE: This is to gain access to remove Torx
screw and MV2 shift control valve.
3.Note their fitted position and disconnect
multiplugs from shift control valves MV 1 and
MV 2.
4.Remove Torx screw and retaining fork securing
MV2 shift control solenoid valve to valve body.
Note that the tag on the retaining fork faces
towards the valve body.
5.Remove shift control valve from valve body.Refit
1.Clean MV2 shift control solenoid valve with lint
free cloth.
2.Position MV2 shift control solenoid valve to
valve body.
3.Position retaining fork, fit Torx screw and
tighten to 8 Nm (6 lbf.ft).
4.Connect multiplugs to both shift control
solenoid valves.
5.Clean lock-up solenoid valve assembly with a
lint-free cloth.
6.Position lock-up valve assembly, fit and tighten
Torx screws to 8 Nm (6 lbf.ft).
7.Fit valve body assembly.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.
M44 13521
M44 1353A

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-57
Harness - solenoid valves
$% 44.15.52
Remove
1.Remove valve body assembly.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.
2.Release and remove clip securing pressure
regulator solenoid harness to valve body.
3.Disconnect multiplug from pressure regulator
solenoid valve.
4.Disconnect multiplugs from lock-up solenoid
valve, shift control solenoid valves MV 1 and
MV 2.
5.Release harness from 5 clips on valve body
and remove harness.6.Disconnect and remove speed sensor from
harness.
Refit
1.Connect speed sensor to harness multiplug.
2.Position harness to valve body.
3.Connect multiplugs to shift control solenoid
valves MV 1 and MV 2 and lock-up solenoid
valve.
4.Connect multiplug to pressure regulator
solenoid valve and secure solenoid valve
harness with clip to valve body.
5.Position and secure harness in clips on valve
body.
6.Fit valve body assembly.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.
M44 1350
M44 1355
M44 1359

REAR AXLE
51-12 OVERHAUL
Inspect
1.Clean and inspect all components for wear and
damage.
2.Fit planet gears and rotate to align cross shaft
holes.
3.Fit cross shaft, ensure roll pin hole is aligned.
4.Secure cross shaft with new roll pin.
5.Fit crown wheel to carrier, fit new bolts and
tighten to 60 Nm (44 lbf.ft).
6.Ensure original head bearing shim is clean and
free from burrs and fit under bearing race.
7.Ensure pinion bearing cup recesses are clean
and free of burrs and using LRT-51-018-4 fit
pinion head and tail bearing races.
8.Fit pinion head bearing to pinion.
9.Lubricate bearings with thin oil.
10.Ensure original tail bearing shim is clean and
free from burrs and fit under bearing race.
11.Fit pinion and pinion tail bearing.
12.Fit pinion flange, washer and bolt.
13.Use LRT-51-003 to restrain pinion flange.
14.Tighten pinion flange bolt to 100 Nm (74 lbf.ft).
15.Check pinion for end float. Should read zero.16.Rotate pinion several times to settle bearings,
check pinion Torque to Turn. Torque to Turn
should be recorded during pinion rotation.
Pinion Torque to Turn should be 4 to 6 Nm (3 to
4.5 lbf.ft).
17.Adjust size of tail bearing shim to obtain correct
pinion Torque to Turn (0.025 mm = 1 Nm
(0.001' = 0.7 lbf.ft) approximately).
18.Position LRT-51-018-7 on surface plate,
establish zero and reference DTI.
19.Ensure pinion height setting block, setting
gauge and mating faces are clean and free
from burrs.
20.Locate setting block LRT-51-018/11 over
pinion head, ensure it is fully seated in position.

REAR AXLE
OVERHAUL 51-13
21. Pinion height setting procedure:
l'A' = Nominal pinion height setting, 74.390.
l'B' = Setting block height.
l'C' = Head height setting.
l'C' = 'A' - 'B'. Subtract nominal pinion height
'A' from setting block height 'B' (on side of
setting block).
lExample: 74.390 - 73.130 = 1.26 mm
(2.929' - 2.88' = 0.049'). Therefore pinion
head height reading is 1.260 mm ± 0.025
mm (0.049' ± 0.001').
CAUTION: Setting block height must be
checked using figures on side of block.
22.Align setting gauge LRT-51-018/7 to setting
block, rock gauge to obtain minimum reading. If
reading is lower than required reading,
decrease shim size. If reading is higher than
required reading, increase shim size.
23.Using LRT-51-003 to restrain pinion flange,
remove bolt and washer. Remove pinion
flange.
24.Remove pinion, collect tail bearing and tail
bearing shim.
25.Remove pinion head bearing outer race and
shim. Discard shim. Ensure bearing race
recess is clean and free from burrs.26.Fit calculated shim, and using LRT-51-018/4 fit
head bearing outer race.
27.Fit pinion, pinion tail bearing and tail bearing
shim.
28.Fit pinion flange and bolt and washer. Using
LRT-51-003 to restrain pinion flange, tighten
bolt to 100 Nm (74 lbf.ft).
29.Rotate pinion in both directions to settle
bearings.
30.Recheck pinion Torque to Turn, adjust if
necessary.
31.Recheck pinion head height.
32.Using LRT-51-003 to restrain pinion flange,
remove bolt and washer. Remove pinion
flange.
33.Discard bolt.
34.Using LRT-51-010 fit pinion seal.
35.Ensure spacer and tail bearing are correctly
located.
36.Fit pinion, pinion flange and washer.
37.Fit new pinion flange bolt and tighten to 100 Nm
(74 lbf.ft).
38.Lightly oil differential bearings.
39.Ensure spring dowels are fitted in bearing caps.
40.Fit differential bearing outer races and locate
differential assembly into housing.
41.Fit bearing caps and tighten bolts to 10 Nm (7.5
lbf.ft).

STEERING
DESCRIPTION AND OPERATION 57-3
1Air bag module
2Steering wheel and nut
3Horn switch 2 off
4Radio remote control switch (if fitted)
5Column switches
6Lower nacelle
7Column tilt adjustment lever
8Steering column lock
9Ignition switch and harness
10Upper column assembly
11Lower column
12Universal joint 13Bolt
14Bolt
15Intermediate shaft assembly
16Decouple joint
17Rubber coupling and heat shield
18Bolt
19Universal joint
20Shear bolt 2 off
21Rotary coupler
22Upper nacelle
23Cruise control switch (if fitted)

STEERING
57-4 DESCRIPTION AND OPERATION
Steering box
RH drive shown, LH drive similar
1Housing with output shaft lower bearing
2Input shaft dirt shield, circlip, backup washer
and pressure seal
3Relief valve stop, seal and locknut 2 off
4Piston/rack adjuster
5Hydraulic pipe
6Piston/rack and relief valves
7Output shaft
8Seal, washer and backup seal
9Circlip and dirt shield
10Teflon and rubber seal 2 off
11Cylinder cover, seal and snap ring12Bearing adjuster, locknut and seal
13Bearing 2 off
14Worm gear and rotary control valve assembly
15Teflon seals 3 off
16Worm/valve shims
17Cover plate seal
18Output shaft adjuster
19Cover plate and bearing
20Bleed screw
21Output shaft adjuster lock nut and seal
22Cover plate bolts 4 off

STEERING
DESCRIPTION AND OPERATION 57-5
Description
General
The major steering components comprise an impact absorbing telescopic steering column, a Power Assisted Steering
(PAS) box, a PAS pump, and fluid reservoir. Hydraulic fluid from the fluid reservoir is filtered and then supplied
through the suction line to the inlet on the PAS pump. The PAS pump supplies fluid to the steering box through a
pressure line routed above the front cross member. Fluid returns to the reservoir along the same route through a
return line. On LH drive vehicles the pipe route above the front cross member is still used, the length of pipe acting
as an oil cooler.
To minimise driver's injury in the event of an accident the steering system has a number of safety features including
a collapsible steering column. An additional safety feature is an air bag located in the steering wheel.

+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description - SRS.
Steering column assembly and intermediate shaft
The steering column central shaft comprises of two shafts, the upper shaft is splined to accept the steering wheel and
located in bearings in the column tube. A universal joint is located on the bottom of the upper shaft, the joint allows
for angular movement between the upper and lower shafts. The lower shaft is made in two parts, the top section of
the lower shaft is located outside of the lower section. The two sections of the lower shaft are connected by two nylon
injection moulded shear pins. The lower shaft goes through a lower bearing attached to the bulkhead, the lower shaft
is connected by a universal joint to the intermediate shaft in the engine compartment.
Steering column
An upper column tube provides for the location of the steering lock and ignition switch and also the steering switch
gear and a rotary coupler. The rotary coupler provides the electrical connection for the steering wheel mounted airbag,
switches and horn. The upper mounting bracket has two slots, a slotted metal bracket is held in each slot by four resin
shear pins.
The column is mounted on four captive studs which are located on a column mounting bracket. The captive studs
pass through the metal brackets, locknuts secure the steering column to the bulkhead. The two lower mountings are
fixed and cannot move when loads are applied to them. The upper mounting is designed to disengage or deform when
a load is applied, allowing the column to collapse in the event of an accident. The steering column must be replaced
as a complete assembly if necessary.
When an axial load is applied to the upper column tube, energy absorption is achieved by the following mechanism:
lthe mounting bracket deforms,
lthe resin shear pins holding the slotted metal brackets shear,
lthe top mounting bracket slides out of the slotted metal brackets.
The slotted metal brackets remain on the captive studs on the bulkhead. If the column mounting moves, injection
moulded shear pins retaining the two sections of the lower column shaft will shear. This allows the two sections of the
lower shaft to 'telescope' together.
In the event of a collision where the steering box itself moves, two universal joints in the column allow the intermediate
shaft to articulate, minimising movement of the column towards the driver. If movement continues energy absorption
is achieved by the following mechanism:
lthe decouple joint in the intermediate shaft will disengage,
lthe lower section of the steering column shaft will move through the lower bearing,
lthe injection moulded shear pins retaining the two sections of the lower column shaft will shear.
This allows the two sections of the lower shaft to 'telescope' together reducing further column intrusion. Protection to
the drivers face and upper torso is provided by an SRS airbag module located in the centre of the steering wheel.

+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description - SRS.

STEERING
57-6 DESCRIPTION AND OPERATION
Tilt adjustment
The column tilt adjuster lever mechanism is located on the LH side of the steering column and allows the upper column
tube, nacelle and steering wheel assemblies to be tilted up or down a maximum of 7.5° or 47 mm (NAS vehicles have
a smaller range of movement than the ROW vehicles).
The pawl of the mechanism is attached to the lower column and is allowed to pivot, a toothed quadrant is fixed to the
upper column tube.
When the lever on the LH side of the steering column is raised the mechanism releases the pawl from the toothed
quadrant, this allows the column to be moved. When the lever is released two return springs pull the pawl into
engagement with the toothed quadrant.
Steering column lock (All except NAS)
The steering column lock houses the ignition switch, ignition illumination light ring, key lock barrel and the alarm
passive coil. The steering lock is attached to the upper column with two shear bolts. The bolts are tightened to a
torque which shears off the heads of the bolts preventing easy removal of the steering lock.
The steering lock operates by a bolt, which emerges when the ignition key is turned to position 'O' and the ignition key
removed. The bolt engages in a lock collar located on the upper shaft in the upper column tube. The lock collar is
attached to the upper shaft by a 'wave form' interference ring. If a high torque is applied via the steering wheel with
the lock engaged, the lock collar will slip on the upper shaft. This prevents damage to the steering lock, yet still
prevents the vehicle from being driven.
Steering column lock (NAS only)
The steering column lock houses the ignition switch, ignition illumination light ring, key lock barrel and the alarm
passive coil. The steering lock is attached to the upper column with two shear bolts. The bolts are tightened to a
torque which shears off the heads of the bolts preventing easy removal of the steering lock.
The steering column lock operates by a bolt, which emerges when the ignition key is turned to position 'O' and the
ignition key removed. The bolt engages in a groove machined into the upper shaft in the column tube.
Steering wheel
The steering wheel comprises a cast centre and wire frame onto which the soft polyurethane foam is moulded. The
steering wheel is located on the upper column shaft by a spline and is secured with a nut. A remote radio control switch
(if fitted) is located on the LH side of the steering wheel, a cruise control switch may be located on the RH side. Horn
switches are located on each side of the centre of the steering wheel and protrude through the airbag module cover.
Both switches are connected by wires to the rotary coupler connector.
Intermediate shaft
One end of the intermediate shaft is attached to the steering column lower shaft by a splined universal joint and a bolt,
the universal joint is part of a rubber coupling assembly. The rubber coupling assembly is covered by a heat shield
and connects to the lower section of the intermediate shaft via a decouple joint. The rubber coupling reduces the
shocks felt by the driver through the steering wheel. A second universal joint on the other end of the intermediate shaft
is held in by a bolt. The universal joint is splined and engages with the splined rotor (input) shaft of the steering box.
The decouple joint consists of a metal plate that has open ended slots, the plate is bolted through the slots into the
other half of the decouple joint. The top half of the decouple joint has a slot that accepts the lower section of the
intermediate shaft. The slotted metal plate clamps the lower section of the intermediate shaft to the top section. An
indicator clip is installed between the slotted metal plate and the top half of the decouple joint.
If the intermediate shaft is compressed in an accident, the slotted metal plate in the decouple joint will disengage if
sufficient force is applied to the front end of the shaft. If the forces involved do not disengage the shaft, the red
indicator clip located in the decouple joint will break off if the shaft moves. The intermediate shaft cannot be repaired
and must be replaced as an assembly if accident damage occurs.