clutch LAND ROVER DEFENDER 1996 User Guide

12ENGINE
16
REPAIR CRANKSHAFT REAR OIL SEAL
Service repair no - 12.21.20
Remove
NOTE: The crankshaft rear oil seal is
retained in its own housing, if the seal
requires replacing, the complete housing
assembly (1) must be renewed. Housing and seal
assemblies are supplied with their own
former/seal guide (2) already fitted. This former
must not be removed before fitting the assembly
to the engine. If a seal and housing assembly is
received without a former/guide fitted it must be
returned to the supplier. Used formers/guides
must be discarded immediately after use, under
no circumstances should they be reused on other
assemblies.
NOTE: A different rear oil seal housing,
with integral 'O' ring seal and gasket, was
fitted on earlier engines. They must be
replaced with the current housing and gasket (3)
shown below.
1.Disconnect battery.
2.Remove gearbox.
See MANUAL GEARBOX,
Repair, R380 gearbox
3.Remove clutch.See CLUTCH, Repair, Clutch
assembly
4.Remove flywheel.See Flywheel
5.Remove 5 bolts and withdraw seal housing,
complete with gasket.
Refit
NOTE: The raised side of groove at the
bottom of seal housing gasket must be
fitted to cylinder block face.
6.Insert slave studs to locate seal housing gasket.
7.Position new gasket over slave studs and
crankshaft flange onto cylinder block.
8.Fit new seal housing assembly, with
former/guide in-situ, over crankshaft flange. This
action will eject former/guide.
9.Secure assembly to cylinder block, removing
slave studs individually and inserting bolts.
Tighten to
25 Nm (18 lbf/ft).
10.Refit flywheel.See Flywheel

ENGINE
17
REPAIR 11.Refit clutch.
See CLUTCH, Repair, Clutch
assembly
12.Refit gearbox.See MANUAL GEARBOX,
Repair, R380 gearbox
13.Reconnect battery.
CRANKSHAFT BEARING BUSH
Service repair no - 12.21.45
Remove
1.Disconnect battery.
2.Remove gearbox.
See MANUAL GEARBOX,
Repair, R380 gearbox
3.Remove clutch.See CLUTCH, Repair, Clutch
assembly
4.Remove flywheel.See Flywheel
5.Remove bearing bush.
NOTE: The bearing bush can be removed
by using one of the following methods.
Method 1.
Obtain a short length of steel rod of a diameter having
a good slide fit in the bore of the bush. Pack the bore
with grease and insert the steel rod into the end of the
bore, give a sharp blow with a hammer and the
grease should drive out the bush. It is recommended
that the bush and rod be covered by a suitable cloth
or rag to prevent grease from splashing.Method 2.
Thread the bore of the existing bush and using a
suitable bolt extract the bush. Thoroughly clean bush
location ensuring all swarf is removed.
Refit
1.Fit new bush using a suitable shouldered drift,
inserting bush flush with end of crankshaft.
2.Refit flywheel.
See Flywheel
3.Refit clutch.See CLUTCH, Repair, Clutch
assembly
4.Refit gearbox.See MANUAL GEARBOX,
Repair, R380 gearbox
5.Reconnect battery.

12ENGINE
18
REPAIR FLYWHEEL HOUSING
Service repair no - 12.53.01
Remove
1.Disconnect battery.
2.Remove gearbox.
See MANUAL GEARBOX,
Repair, R380 gearbox
3.Remove clutch.See CLUTCH, Repair, Clutch
assembly
4.Remove flywheel.See Flywheel
5.Remove 3 fixings and withdraw starter motor.
6.Remove 2 bolts from top of flywheel housing.
7.Remove 4 bolts securing bottom of flywheel
housing to engine mounting brackets.
8.Remove inner bolts and lift off flywheel housing.Refit
9.Clean rear face of housing and mating face on
block, ensuring all old sealant is removed.
10.Apply sealant to flywheel housing mating face on
cylinder block.
11.Fit housing to cylinder block. Tighten retaining
bolts to
45 Nm (33 lbf/ft).
12.Remove surplus sealant from block.
13.Fit starter motor.
14.Fit flywheel.
See Flywheel
15.Fit clutch.See CLUTCH, Repair, Clutch
assembly
16.Fit gearbox.See MANUAL GEARBOX, Repair,
R380 gearbox
17.Reconnect battery.

ENGINE
1
SPECIFICATIONS, TORQUE REV: 05/99 TORQUE VALUES
NOTE: Torque wrenches should be regularly checked for accuracy to ensure that all fixings are
tightened to the correct torque.
Nm
Engine block
Bearing cap 133...............................................................................................
Blanking plug, oil gallery, rear 37....................................................................
Oil squirt jet assembly 17................................................................................
Drain plug, cylinder block 25...........................................................................
Oil squirt jet, vacuum pump cam 7.................................................................
Connecting rod to cap 59................................................................................
Oil pick up assembly to bearing cap 9...........................................................
Oil pick up assembly to front cover 25............................................................
Camshaft thrust plate 9..................................................................................
Oil drain pipe to block (internal) 25.................................................................
Oil drain pipe to block (external) 25................................................................
Sump to cylinder block and front cover 25......................................................
Drain plug, oil sump 35...................................................................................
Tappet guide 14..............................................................................................
Breather side cover assembly 25....................................................................
Baffle plate to breather side cover 4..............................................................
Vacuum pump 25............................................................................................
Fuel lift pump 25.............................................................................................
Flywheel housing 45.......................................................................................
Flywheel housing clutch cover stud 10...........................................................
Plug, flywheel housing 12...............................................................................
Rear oil seal assembly 25...............................................................................
Oil filter adaptor 45..........................................................................................
Waxstat adaptor to oil filter adaptor 9............................................................
Oil pressure switch 17.....................................................................................
Oil filter, spin on 13.........................................................................................
Oil cooler unions to filter adaptor 45...............................................................
Oil level tube 25..............................................................................................
Engine mounting foot to cylinder block 85......................................................
Engine mounting foot to flywheel housing 45.................................................
Engine mounting foot rubber to mounting foot (bolt and nut) 85.....................
Flywheel to crankshaft 146..............................................................................
Clutch cover plate to flywheel 34....................................................................
Flex drive plate to crankshaft (auto) 146..........................................................
Flex drive plate to ring gear (auto) 25.............................................................
Flex drive plate to torque converter (auto) 45.................................................

26COOLING SYSTEM
4
DESCRIPTION AND OPERATION Operation
To engage and disengage the fan drive the bi-metal
coil senses air temperature behind the radiator. When
a pre-determined temperature is reached, the coil
opens a valve (5) which allows fluid to enter the drive
area and, due to centrifugal force, circulates to the
annular drive area.
There are two sets of annular grooves (3), one in the
drive clutch and the other in the drive body, a specific
clearance being provided between the two sets of
grooves.
Viscous unit disengaged (engine at normal
running temperature)
1.Input (drive) member
2.Output (driven) member
3.Running clearance
4.Pump plate
5.Valve (closed)
6.Sensing mechanism (bi-metal coil)
7.Fluid seal
8.Bearing, input member
9.Fluid chamber
10.Fluid reservoirWhen this clearance is filled with viscous fluid, a
shearing action, caused by the speed differential
between the two drive components, transmits torque
to the fan. The fluid is thrown to the outside of the unit
by centrifugal force from where it is recirculated to the
reservoir (10) via the pump plate (4) adjacent to the
drive member.
If the engine speed is increased the amount of slip will
also increase to limit the maximum fan speed.
When the air temperature from the radiator drops
sufficiently, the bi-metal coil closes the valve and
prevents fluid entering the drive area. The fluid that is
in the drive area will gradually pump out into the
reservoir (10) and the fan will return to an idle
condition.
Viscous unit engaged (hot running temperature)
Bi-metal coil (6) expanded, valve (5) open.

CLUTCH
1
DESCRIPTION AND OPERATION DESCRIPTION
The clutch unit comprises a single dry plate friction
disc and diaphragm spring clutch unit, secured to the
engine flywheel.OPERATION
The unit is operated hydraulically by the clutch master
cylinder (12) and a slave cylinder (13) attached to the
transmission bell housing.
Clutch components
1.Crankshaft and flywheel
2.Friction plate
3.Clutch cover
4.Diaphragm spring
5.Pressure plate
6.Fulcrum posts (9) for diaphragm spring
7.Bearing rings (2) for diaphragm spring
8.Retraction links and bolts (3) for pressure plate
9.Release bearing10.Release lever
11.Release lever pivot post
12.Master cylinder
13.Slave cylinder
14.Master cylinder pedal pushrod
15.Primary shaft and taper bearing (in gearbox)
16.Gearbox front cover
17.Primary shaft flywheel bush
18.Pedal pivot and return spring

33CLUTCH
2
DESCRIPTION AND OPERATION
When the clutch pedal is depressed, hydraulic fluid
transmits the movement via the slave cylinder, release
lever (10), bearing (9), to the inner fingers of the
diaphragm spring (4).
The diaphragm spring (4) pivots on the bearing rings
(7) and fulcrum posts (6) causing the pressure plate
(5) to release the clamping force on the friction plate
and linings (2).As the the clamping force is removed from the friction
plate (2), the plate slides on the splines of the primary
shaft (15) and takes up a neutral position between the
flywheel (1) and the pressure plate (5), thus
disconnecting the drive between the engine and the
gearbox.

CLUTCH
1
FAULT DIAGNOSIS CLUTCH ASSEMBLY CONDITIONS
For the clutch to operate correctly it is important the
following conditions are satisfied:-
·The primary shaft (15) must be free in the
crankshaft spigot bush (17).
·The friction plate (2) must be able to slide easily on
the splines on the primary shaft (15), to a position
where it does not contact either the flywheel or the
pressure plate.
·The friction plate must not be distorted or the
linings contaminated with oil, which may cause it to
stick or continue to run in contact with the flywheel
or pressure plate.
A number of faults can develop in the operation of the
clutch for a variety of reasons and most faults are due
to normal wear at high mileage. Problems can also
occur if the unit has been renewed by an unskilled
operator.
Recognising and diagnosing a particular clutch fault is
therefore of paramount importance in ensuring that
the problem is rectified at the first attempt.
Problems which develop in the clutch are as follows:-
·Clutch spin/drag
·Clutch slip
·Clutch judder/fierceCLUTCH SPIN - DRAG
Symptoms
Clutch spin is that, with engine running and clutch
pedal depressed, the gears cannot be immediately
engaged without making a grinding noise. This
indicates the clutch is not making a clean break.
However, if the clutch pedal is held depressed for
several seconds the friction plate will eventually break
free from the engine and the gear will engage silently.
Clutch spin as it becomes more severe develops into
clutch drag, making the silent engagement of a gear
impossible, regardless of how long the pedal is held
depressed.
CLUTCH SLIP
Symptoms
Clutch slip is most evident climbing a hill or when the
vehicle is moving off from stationary with a heavy
load. As the clutch is released, slip occurs between
the engine and the transmission, allowing the engine
speed to increase without a corresponding increase in
vehicle speed.
Clutch slip can develop to the stage where no power
is transmitted through the clutch as the pedal is
released.
CLUTCH JUDDER - FIERCE
Symptoms
Clutch judder or fierce engagement, like slip, is most
likely to occur when the vehicle is moving off from
stationary. As the clutch pedal is released the vehicle
will move rapidly or in a series of jerks, which cannot
be controlled even by careful operation of the clutch
by the driver.
It should be noted that a vehicle may display all the
symptoms or any combination of the symptoms
described, depending on the driving conditions vehicle
load and operating temperatures.

33CLUTCH
2
FAULT DIAGNOSIS FAULT/SYMPTOM CHART
Symptoms
Slip Spin/Drag Judder/Fierce Fault Item
* * * Worn or oil on clutch linings 2
* * * Mechanical damage45678
* * Distorted clutch plate 2
* Failed or air in hydraulic system 12 13
* * Primary shaft tight fit in crankshaft bush 15 17
* Clutch splines sticking 2 15
* Weak clutch plate springs or insecure/worn
engine/gearbox mountings6
* Insecure/worn propeller shafts
* Insecure/worn suspension components/rubber
bushes
The items refered to in this chart relate to the clutch components shown in J6270 and J6271.See Description
and operation, Description
CLUTCH NOISE - MECHANICAL FAULTS
Noise from clutch or gearbox in neutral, which
disappears when clutch is depressed.
Suspect gearbox input/primary shaft bearings
See MANUAL GEARBOX, Fault diagnosis,
R380 gearbox
.
Noise from clutch or gearbox in neutral, which
changes tone or becomes worse when the clutch
is depressed.
Suspect worn release bearing.
Knocking/rattling from clutch or gearbox in
neutral, which is reduced or disappears when the
clutch is depressed.
Suspect worn/weak release lever retainer or
clutch unit.
Noise from clutch or gearbox in neutral, which
disappears when clutch is depressed.
Suspect gearbox fault
See MANUAL
GEARBOX, Fault diagnosis, R380 gearbox
.HYDRAULIC FAULTS
Unable to dis-engage clutch, little or no pedal
resistance.
1.Check condition, specification and level of fluid.
2.Check pipes and cylinders for leaks.
3.Check that air vent in reservoir lid is clear.
Suspect faulty master cylinder if no fluid leaks
present
See Repair, Master cylinder.
Spongy pedal operation
1.Check condition, specification and level of fluid.
2.Check that air vent in reservoir lid is clear.
Suspect air in fluid
See Repair, Bleed
hydraulic system
.
Clutch is difficult to dis-engage and/or does not
immediately re-engage when pedal is released.
1.Check condition, specification and level of fluid.
2.Check that air vent in reservoir lid is clear.
Suspect pedal pivot, master cylinder or slave
cylinder seizure
See Repair, Master cylinder.

CLUTCH
1
ADJUSTMENT CLUTCH PEDAL AND MASTER CYLINDER
SETTING
1.Remove 6 screws and detach pedal box top
cover and gasket.
2.Slacken both locknuts on master cylinder
push-rod.
3.Check distance from lower edge of clutch pedal
to floor. Correct measurement is 140 mm (5.50
in) without floor mat.
4.Adjust pedal stop as necessary to obtain correct
setting.
5.Adjust master cylinder push rod to obtain
approximately 1,5 mm (1/16 in) free play
between push-rod and master cylinder piston.
6.Tighten push-rod locknuts.7.Check operation of clutch pedal and ensure that
there is a minimum of 6 mm (0.25 in) of free play
before pressure is felt. If necessary, readust
master cylinder push-rod.
8.Fit pedal box gasket and top cover.