tyre pressure LAND ROVER DISCOVERY 1995 Service Repair Manual

INTRODUCTION
7
INFORMATION DYNAMOMETER TESTING - VEHICLES WITH
ANTI-LOCK BRAKES (ABS)
WARNING: Do not attempt to test ABS
function on a dynamometer
Four wheel dynamometers
NOTE: Before testing a vehicle on a four
wheel dynamometer disconnect the valve
relay.
See Electrical Trouble Shooting
Manual.
The ABS function will not work, the ABS warning
light will illuminate. Normal braking will be
available.
Provided that front and rear rollers are rotating at
identical speeds and that normal workshop safety
standards are applied, there is no speed restriction
during testing except any that may apply to the tyres.
Two wheel dynamometers
IMPORTANT: Use a four wheel dynamometer for
brake testing if possible.
NOTE: ABS will not function on a two
wheel dynamometer. The ABS light will
illuminate during testing. Normal braking
will be available.
If brake testing on a single rig is necessary it must be
carried out with propeller shaft to the rear axle
removed, AND neutral selected in BOTH main and
transfer boxes.
If checking engine performance, the transfer box must
be in high range and drive shaft to stationary axle
removed.
TOWING
CAUTION: The vehicle has permanent
four-wheel drive. The following towing
instructions must be adhered to:
Towing the vehicle on all four wheels with driver
operating steering and brakes.
1.Turn ignition key turn to position '1' to release
steering lock.
2.Select neutral in main gearbox and transfer
gearbox.
3.Secure tow rope, chain or cable to towing eye.
4.Release the parking brake.
CAUTION: The brake servo and power
assisted steering system will not be
functional without the engine running.
Greater pedal pressure will be required to apply
the brakes, the steering system will require
greater effort to turn the front road wheels.
The vehicle tow connection should be used only
in normal road conditions, 'snatch' recovery
should be avoided.
Suspended tow by breakdown vehicle
CAUTION: To prevent vehicle damage,
front or rear propeller shaft MUST BE
removed, dependent upon which axle is
being trailed.
1.Mark propeller shaft drive flanges at transfer
gearbox and axles with identification lines to
enable the propeller shaft to be refitted in its
original position.
2.Remove the propeller shaft fixings, remove the
shaft from the vehicle.
3.If the front axle is to be trailed turn ignition key to
position '1' to release steering lock.
CAUTION: The steering wheel and/or
linkage must be secured in a straight
ahead position. DO NOT use the steering
lock mechanism for this purpose.

INTRODUCTION
13
INFORMATION European vehicle identification number (VIN)
Stamped on the right hand side chassis forward of
rear wheel.
Federal (USA) vehicle identification number
Stamped on a plate rivetted to the upper left hand 'A' -
post, visible through the front screen of the vehicle.Vehicle identification number (VIN)
An adhesive label containing the Vehicle Identification
Number, date of manufacture and gross axle weight
ratings is fixed to the lock face of the front left hand
door. The information includes wheel and tyre sizes
and tyre pressures at gross axle weight ratings.
Key to vehicle identification label
A.Month and year of manufacture
B.Gross vehicle weight rating
C.Gross axle weight rating for front axle
D.Gross axle weight rating for rear axle
E.Vehicle identification number (17 digits)
F.Vehicle identification number - bar code

GENERAL SPECIFICATION DATA
17
INFORMATION TYRE PRESSURES
Pressures: Check Normal on and off-road use. Off-road 'emergency' soft use
maximum
with tyres cold All speeds and loads speed of 40 kph (25 mph)
205R16 Radial Front Rear Front Rear
bars 1.9 2.6 1.2 1.8
lbf/in
228 38 17 25
kgf/cm22.0 2.7 1.2 1.8
WARNING: Vehicles fitted with tubeless alloy road wheels as original equipment, note that these
wheels DO NOT accept inner tubes and tubed tyres MUST NOT be fitted.
NOTE: Emergency soft pressures should only be used in extreme conditions where extra
floatation is required. Max speed 40km/h (25mph).
WHEELS AND TYRES
Type and size Alloy 7.00J X 16...................................................................
Tyre size 205R16 (tubeless)..........................................................................
Type and size Steel 6.00JK X 16...................................................................
Tyre size 205R16 (tubed)..........................................................................
'Freestyle' choice tyre specification
Tyre size 235/70 R16..........................................................................
Front Rear
Tyre pressure 26 lbf/in
2................................................................... 34 lbf/in2
NOTE: Petrol vehicles must be fitted with 'S' or 'T' rated tyres.

MAINTENANCE
3
MAINTENANCE VEHICLE EXTERIOR
CHECK/ADJUST HEADLAMP ALIGNMENT
Check/adjust headlamp and auxiliary alignment.
CHECK FRONT WHEEL ALIGNMENT
Use recognised wheel alignment equipment to
perform this check and adjustment.
See STEERING,
Adjustment, Front Wheel Alignment
REMOVE WHEELS, CHECK TYRES
Check tyres (including spare) for compliance with
manufacturers' specification.
Check visually for cuts, lumps, bulges, uneven tread
wear and tread depth. Check road wheels for
damage.
Check/adjust tyre pressures.
CHECK/TIGHTEN TOWING BRACKET FITTINGSINSPECT BRAKE PADS FOR WEAR, CALIPERS
FOR LEAKS AND CONDITION
Check thickness of brake pads, fit new pads if
minimum thickness is less than 3,0mm. Check brake
pads for oil contamination. If new brake pads required.
See BRAKES, Repair, Front Brake Pads
or.See BRAKES, Repair, Rear Brake Pads
WARNING: When renewing brake pads, it
is essential that only genuine components
with correct grade of lining are used.
Always fit new pads as complete axle sets, NEVER
individually or as a single wheel set. Serious
consequences could result from out of balance
braking due to mixing of linings.
Refit road wheels
Fit road wheels in original hub position. Secure in
position with wheel nuts, do not fully tighten wheel
nuts at this stage, lower vehicle and finally tighten
wheel nuts to correct torque.
Alloy wheels:
130 Nm.
Steel wheels:130 Nm.
LUBRICATE ALL HINGES, DOOR CHECK
MECHANISMS, BONNET [HOOD] CATCHES AND
FUEL FILLER FLAP

57STEERING
4
FAULT DIAGNOSIS Symptom:-
Fluid leaks from steering box seals.
CAUTION: The steering wheel must not be
held on full lock for more than 30 seconds
in one minute, as this may overheat the
fluid and cause damage to the oil seals.
1.Check fluid level.
See Repair, Power Steering
Fluid Reservoir
Check fluid pressure.See Power Steering
System - Test
2.Is pressure high?
YES - Renew pump.
See Repair, Power
steering Pump
If oil seal leaks persist after renewing the
pump.
See Overhaul, Power Steering
Box
NO -See Overhaul, Power Steering Box
Symptom:-
Insufficient power assistance - castor return
action normal.
1.Are tyres correct type and pressure?
NO -
See GENERAL SPECIFICATION DATA,
Information, Wheels and Tyres
YES - Continue.
2.Is fluid level correct?
NO - Check fluid level
See Repair, Power
Steering Fluid Reservoir
YES - Check system for air locks.See Repair,
Power Steering System - Bleed
3.Is pressure correct?
NO - Check fluid pressure.
See Power
Steering System - Test
If pressure is not correct after bleeding
the system, renew pump.
See Repair,
Power Steering Pump
YES -See Overhaul, Power Steering Box
Symptom:-
Steering heavy - stiff, poor castor return action.
1.Are tyres correct type and pressure?
NO -
See GENERAL SPECIFICATION DATA,
Information, Wheels and Tyres
YES - Check universal joints for seizure and
correct alignment.
See Repair, Lower
Steering Shaft and Universal Joints
Check power steering box adjustments.
See Overhaul, Power Steering Box
2.Is the power assistance satisfactory?
NO - See fault symptomInsufficient
assistance, (castor return action
normal).
YES - Disconnect drag link from drop arm and
check steering column and box for
stiffness.
See Repair, Drag Link and
Drag Link Ends
3.Is the steering stiff with the drag link
disconnected?
NO - Check steering ball joints for seizure and
axle swivels lubrication and resistance.
See Repair, Drag Link and Drag Link
Ends See FRONT AXLE AND FINAL
DRIVE, Overhaul, Front Stub Axle,
Constant Velocity Joint and Swivel Pin
Housing Non ABS See FRONT AXLE
AND FINAL DRIVE, Overhaul, Front
Stub Axle, Constant Velocity Joint and
Swivel Pin Housing ABS
YES - Disconnect the lower steering shaft and
check the column and box for stiffness.
See Repair, Lower Steering Shaft and
Universal Joints
4.Is the steering column stiff to turn when
disconnected from the box?
NO - Remove and overhaul box.
See
Overhaul, Power Steering Box
YES - Adjust steering column.See Stiff
Steering Checklist

57STEERING
10
FAULT DIAGNOSIS VISUAL AND SAFETY CHECKS
WARNING: Before taking vehicle out on
the public highway for road test, it is
important that the following basic visual
checks are carried out to ensure that the vehicle
complies with legal requirements.
Tyres and wheel rims
1.Check and adjust tyre pressures.
See
GENERAL SPECIFICATION DATA,
Information, Tyre Pressures
Note that this information refers to standard tyres
fitted as original equipment.
2.Check condition of tyres. Inspect for signs of
uneven wear, damage and feathering. Check
tread depth.
3.Ensure that the tyre make, type and general
condition are common across each axle.
4.Check wheel rims for signs of damage and
excessive run out.
5.Carry out road test.
See Road Test Procedure
ROAD TEST PROCEDURE
General steering/handling problems can usually be
classified into one of the categories listed and ARE
GENERALLY RELATED TO THE AGE, CONDITION
AND USE OF THE VEHICLE.
WARNING: Ensure that all road tests are
conducted by suitably qualified drivers in
a safe and legal manner, and where local
traffic conditions allow.
1.Carry out visual and safety checks.
See Visual
and Safety Checks
Confirm general nature of complaint with customer,
simulating where possible the conditions under which
the problem occurs. Carry out following road test
procedure to establish the problem.2.Steering load assessment - drive at 16 km/h (10
mph). Put 90°turn input into steering wheel,
check self centering. The self centering should
be equal on each lock BUT not necessarily
return to exactly straight ahead without
assistance from the driver.
3.Steering assessment - drive at 64 km/h (40 mph)
on a staight FLAT road (no camber), check for
steering veer. The vehicle should follow a
straight path with NO tendency to follow a
curved path. If vehicle veers towards the kerb,
vehicle may be 'camber sensitive'. A small
amount of veer in direction of camber is
acceptable.
4.Directional stability assessment - drive at 112
km/h (70 mph) or maximum legal speed on a
straight flat road. Carry out a normal lane
change. Vehicle should quickly settle into a new
straight path.
5.Braking assessment (medium effort) - drive at 96
km/h (60 mph) on a straight flat road. Apply
steady medium braking effort, noting any
tendency to veer. Carry out brake test three
times, if a veer is consistently noted carry out a
braking efficiency test on a rolling road.
6.Braking assessment (full effort) - drive at 96
km/h (60 mph) on a straight flat road. Apply full
braking effort, noting any tendency to veer. Carry
out brake test three times, if a veer is
consistently noted carry out a braking efficiency
test on a rolling road.
If the symptom described by the customer is stiff
steering or steering niggle, carry out stiff steering
procedure.
See Stiff Steering Checklist
If not proceed with basic checks and adjustments.
See Visual Check and Basic Adjustments

BRAKES
3
DESCRIPTION AND OPERATION Description of components
1. ABS Modulator unit
To provide the ABS function a Modulator is positioned
within the system between the master cylinder and the
calipers. On both LHD and RHD vehicles it is sited on
the left inner wing [fender]. The Modulator has 8
solenoid valves, 2 for each wheel, 2 expanders and a
recirculation pump. It is non serviceable.
2. Servo/master cylinder
Actuation of the system is provided by a combined
master cylinder and servo assembly attached to the
pedal box, this provides pressure to opposed piston
calipers at each brake pad Twin piston at the front
axle, single piston at the rear.
3. Pressure reducing valve
To maintain the braking balance, pressure to the rear
axle is regulated by a Pressure Reducing Valve (PRV)
This PRV is of the failure bypass type, allowing full
system pressure to the rear axle in the event of a front
circuit failure. It is sited on the left inner wing [fender].
4. Electronic control unit - ECU
ABS control is provided by an electronic control unit
which is positioned on the passenger side of the
vehicle behind the dash panel/glove box.
The ECU, which is non-serviceable, is connected to
the ABS harness by a 35 way connector. non
serviceable.
The ECU continually monitors the brake system,
providing diagnostics in the event of a system
malfunction. Details of how to access the ECU
diagnostics are provided in the Electrical
Troubleshooting Manual.
5.& 6. Front and rear sensors/exciter rings - 4 off
A sensor is sited at each wheel, sensing a 60 tooth
exciter ring. When vehicle is in motion inductive
sensors send signals to ECU. Front exciter ring is
fitted to outside diameter of constant velocity joint
inside each front hub assembly. The rear exciter ring
is bolted to the rear of each brake disc bell.7. Diagnostic plug connection
A diagnostic plug is located behind the dash. To the
left of the steering column on LHD vehicles. To the
right of the steering column on RHD vehicles. It is a 5
way blue connector.
The location and identification of ABS electrical relays
are given in the Electrical Troubleshooting Manual.
For location and identification of ABS electrical fuses.
See ELECTRICAL, Repair, Fuse Box - Interioror.
See ELECTRICAL, Repair, Fuse Box - Engine
Compartment
ANTI-LOCK BRAKE SYSTEM - ABS
Manufactured by WABCO
Introduction
The purpose of ABS is to prevent vehicle wheels
locking during brake application, thus maintaining
vehicle steerability and stability. This allows vehicle to
be steered whilst brakes are applied, even under
emergency conditions, and to avoid obstacles where
there is sufficient space to redirect the vehicle.
WARNING: ABS is an aid to retaining
steering control and stability while
braking.
·ABS cannot defy the natural laws of physics
acting on the vehicle.
·ABS will not prevent accidents resulting from
excessive cornering speeds, following
another vehicle too closely or aquaplaning,
i.e. where a layer of water prevents adequate
contact between tyre and road surface.
·The additional control provided by ABS must
never be exploited in a dangerous or
reckless manner which could jeopardise the
safety of driver or other road users.
·The fitting of ABS does not imply that the
vehicle will always stop in a shorter stopping
distance.

WHEELS AND TYRES
1
DESCRIPTION AND OPERATION TYPES OF WHEEL RIMS AND TYRES
Description
Dependent on specification, the vehicle is equipped
with alloy or pressed steel wheel rims, both using
tubeless radial ply tyres.
Tyre codes
The writing, codes and numbers moulded into the tyre
wall vary between tyre manufacturers, however most
tyres are marked with the information shown in the
illustrated example.
NOTE: The illustration is an example of the
type of markings moulded into tyres and is
for guidance only. For specific tyre
specifications.
See GENERAL SPECIFICATION
DATA, Information, Wheels and Tyres
1.Type of tyre construction -Radial Ply
2.Load index -104
3.Speed symbol -SorT
4.USA Tyre quality grading -Tread wear 160
Traction A temperature B
5.Tread wear indicators moulded into tread pattern
are located at intervals around the tyre and
marked by a code -E66 103S6
6.Tyres with 'Mud Snow' type tread pattern are
marked -M&S
7.Tyre reinforcing mark -Reinforced
8.USA Load and pressure specification -
900Kg(1984LBS) at 340KA (50PSI) MACS
PRESS
9.Tyre size -205 16 ot 235/70 R16
10.Type of tyre -TUBELESS
11.Country of manufacture -MADE IN GREAT
BRITAIN
12.USA Compliance symbol and identification -
DOT AB7C DOFF 267
13.European type approval identification -E11
01234
14.Tyre construction -SIDE WALL 2 PLIES
RAYON. TREAD 2 RAYON 2 STEEL
15.Manufacturer's brand name/type -TRACTION
PLUS mzx M

WHEELS AND TYRES
1
FAULT DIAGNOSIS TYRE WEAR CHART
FAULT CAUSE REMEDY
Rapid wear at Tyres under-inflated Inflate to correct pressure
shoulders Worn suspension components Replace worn components
i.e. ball joints, panhard
rod bushes,steering damper
Excessive cornering speeds
Rapid wear at
centreTyres over-inflated Inflate to correct pressure
of tread
Wear at one
shoulderTrack out of adjustment Adjust track to correct figure
Bent panhard rod Check and replace worn or damaged
components
Bald spots or tyre Wheel out of balance Balance wheel and tyre
cupping assembly
Excessive radial runout Check runout and replace tyre
if necessary
Shock absorber worn Replace shock
Excessive braking
Tyre scalloped Track out of adjustment Adjust toe to correct figure
Worn suspension components Replace as necessary
Excessive cornering speeds
CAUTION: This diagnosis chart is for general guidance only and does not necessarily include
every cause of abnormal tyre wear.

74WHEELS AND TYRES
2
FAULT DIAGNOSIS FAULT - SYMPTOMS
Vibration through steering wheel
1.Check tyre pressures.
See Repair, Tyre
Pressures
2.Check condition of tyres.See Tyre Wear Chart
3.Check front wheel alignment.See STEERING,
Adjustment, Front Wheel Alignment
4.Check wheel balance.See Repair, Wheel
Balancing
NOTE: In the event that any apparent
vibration is not eliminated at this stage.
See PROPELLER SHAFTS, Fault
diagnosis, Vibration Harshness
NOTE: In the event that any apparent
vibration is not eliminated at this stage, go
to steering Fault Diagnosis, Fault -
Symptom (Steering vibration, road wheel
shimmy/wobble).
See STEERING, Fault diagnosis,
Steering Faults
NOTE: Radial ply tyres have a flexible
sidewall, which produces a sidewall bulge
making the tyre appear under-inflated.
This is a normal condition for radial ply tyres. Do
not attempt to reduce this bulge by over-inflating
the tyre.
1. Correct inflation.
2. Under-inflation.
3. Over-inflation.
4. Tread contact with road.