brake LAND ROVER DEFENDER 1999 Owner's Guide

18ENGINE MANAGEMENT SYSTEM
22
DESCRIPTION AND OPERATION SWITCH - BRAKE PEDAL
The brake pedal switch is located at the rear of the brake pedal box, and activates when the brake pedal is
operated. The ECM uses the signal from the brake pedal to activate the brake lamps and to limit fuelling under
braking.
The brake pedal switch can fail in any of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to earth.
SWITCH - CLUTCH PEDAL
The clutch pedal switch is located on the clutch master cylinder and is activated when the clutch pedal is operated.
The ECM uses the signal from the clutch pedal switch to provide surge damping during gear change. Surge
damping stops engine speed rising dramatically (engine flaring) during gear change. Surge damping assists
driveability as follows:
Smoother gear change.
Greater exhaust gas emission control.
Improved fuel consumption.
Input / Output
When the clutch pedal is in the rest position, the clutch switch is closed. This allows a feed to flow from the switch
(C0667-1) to the ECM (C0658-35) on a black/white wire. When the clutch pedal is pressed the switch contacts
open, cutting the feed to the ECM.
The clutch pedal switch can fail in any one of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
In the event of a clutch pedal switch failure surge damping will be inactive.
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CLUTCH
3
DESCRIPTION AND OPERATION 1.Brake/clutch reservoir
2.Connecting hose
3.Bolt - 2 off
4.Master cylinder
5.Clutch pedal
6.Gearbox housing
7.Primary driveshaft
8.Bolt - 2 off
9.Slave cylinder
10.Bleed nipple
11.Pressure plate
12.Drive plate
13.Dual mass flywheel
14.Metal hydraulic pipe
15.Ball spigot
16.Clutch release bearing sleeve
17.Bolt - 2 off
18.Pivot washer
19.Release lever
20.Release bearing
21.Retaining clip
22.Bolt
23.Plastic hydraulic pipe
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CLUTCH
5
DESCRIPTION AND OPERATION 1.Brake/clutch reservoir
2.Fluid supply pipe
3.Hydraulic feed pipe
4.Damper
5.Master cylinder
6.Piston
7.Clutch pedal
8.Primary driveshaft
9.Engine crankshaft
10.Drive plate
11.Dual mass flywheel
12.Ring gear
13.Leaf spring
14.Cover - pressure plate
15.Diaphragm
16.Release bearing
17.Ball spigot
18.Release bearing sleeve
19.Release lever
20.Slave cylinder
21.Piston
22.Bleed nipple
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33CLUTCH
6
DESCRIPTION AND OPERATION DESCRIPTION
General
The clutch system is a diaphragm type clutch operated by a hydraulic cylinder. The drive plate is of the rigid centre
type with no integral damping springs. The flywheel is of the dual mass type with damping springs integral with the
flywheel. The clutch requires no adjustment to compensate for wear.
Hydraulic Clutch
The hydraulic clutch comprises a master cylinder, slave cylinder and a hydraulic reservoir. The master and slave
cylinders are connected to each other hydraulically by plastic and metal pipes. The plastic section of the pipe
allows ease of pipe routing and also absorbs engine movements and vibrations.
The master cylinder comprises a body with a central bore. Two ports in the body connect the bore to the hydraulic
feed pipe to the slave cylinder and the fluid reservoir. The bore is also connected to a damper which prevents
engine pulses being transferred hydraulically to the clutch pedal. A piston is fitted in the bore and has an external
rod which is attached to the clutch pedal with a pin. Two coil springs on the clutch pedal reduce the effort required
to depress the pedal.
The master cylinder is mounted on the bulkhead and secured with two bolts. The cylinder is connected to the
shared brake/clutch reservoir on the brake servo by a braided connecting hose.
The slave cylinder is located on the left hand side of the gearbox housing and secured with two bolts. A heat
shield is fitted to protect the underside of the slave cylinder from heat generated from the exhaust system. The
slave cylinder comprises a cylinder with a piston and a rod. A port in the cylinder body provides the attachment for
the hydraulic feed pipe from the master cylinder. A second port is fitted witha bleed nipple used for removing air
from the hydraulic system after servicing. The piston rod locates on a clutch release lever located in the gearbox
housing. The rod is positively retained on the release lever with a clip.
Clutch Mechanism
The clutch mechanism comprises a flywheel, drive plate, pressure plate, release lever and a release bearing. The
clutch mechanism is fully enclosed at the rear of the engine by the gearbox housing.
A clutch release bearing sleeve is attached in the gearbox housing with two bolts and located on two dowels. A
spigot with a ball end is formed on the release bearing sleeve and provides a mounting and pivot point for the
clutch release lever. A dished pivot washer is located on the ball of the spigot. When the release lever is located
on the ball, the pivot washer seats against the rear face of the release lever. A spring clip is located on the lever
and the pivot washer and secures the lever on the spigot. A small bolt retains the spring clip in position.
The release lever is forked at its inner end and locates on the clutch release bearing carrier. The outer end of the
release lever has a nylon seat which locates the slave cylinder piston rod. A second nylon seat, positioned
centrally on the release lever, locates on the ball spigot of the release bearing sleeve and allows the release lever
to pivot freely around the ball.
The clutch release bearing locates on the clutch release lever and release bearing sleeve. The bearing is retained
on a carrier which has two flats to prevent the carrier rotating on the release lever. A clip retains the release lever
on the carrier. The bearing and carrier are not serviceable individually.
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CLUTCH
1
ADJUSTMENT HYDRAULIC SYSTEM - BLEED
Service repair no - 33.15.01
Check
CAUTION: Ensure the fluid in the reservoir
is maintained between the minimum and
maximum levels throughout the bleed
procedure using new brake fluid.
CAUTION: Brake fluid will damage paint
finished surfaces. If spilled, immediately
remove fluid and clean area with water.
1.Top up clutch system reservoir.
2.Raise front of vehicle and support on stands.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
3.Remove dust cap, connect bleed tube to bleed
screw and submerge free end into a clear
container of brake fluid.
4.Loosen bleed screw, then apply steady pressure
to the clutch pedal, depressing it through its full
stroke. Allow the pedal to return unassisted.
5.Repeat the procedure until a flow of clean,
air-free fluid is purged into the container.
6.Hold pedal down and tighten bleed screw to9
Nm (7 lbf.ft).
7.Check and top up reservoir.
CAUTION: Never re-use fluid that has been
bled from the system.
8.Remove stands and lower vehicle.
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33CLUTCH
2
REPAIR BEARING - CLUTCH RELEASE
Service repair no - 33.25.12
Remove
1.Remove gearbox assembly.See MANUAL
GEARBOX, Repair.
2.Remove retaining peg and remove release
bearing.
3.Remove bolt securing clutch release fork,
remove retaining clip and remove clutch release
fork.
Refit
4.Clean release fork.
5.Examine clutch release fork pivot points for
wear.
6.Apply a smear of Molybdenum disulphide grease
to release fork pivot points.
7.Fit retaining clip ensuring it locates over pivot
point washer.
8.Fit bolt and tighten to10 Nm (7 lbf.ft).
9.Clean release bearing and bearing sleeve
mating faces.
10.Apply smear of Molybdenum disulphide grease
to release bearing sleeve.
11.Fit release bearing and secure with retaining
peg.
12.Fit gearbox assembly.See MANUAL
GEARBOX, Repair.CLUTCH - MASTER CYLINDER LH DRIVE
Service repair no - 33.20.01
Remove
1.Remove 3 screws securing closing panel to
lower’A’post.
2.Release closing panel sufficient to gain access
to clutch and brake pedal bracket bolts.
3.Remove clutch pedal rubber.
4.Remove 12 bolts securing clutch and brake
pedal brackets to body.
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CLUTCH
3
REPAIR
5.Disconnect multiplug from clutch pedal sensor.
6.Disconnect muliplug and harness clip from pedal
bracket.
7.Position cloth to collect fluid spillage.
8.Loosen pipe union, release pipe and plug pipe
and master cylinder.
9.Move brake master cylinder assembly aside and
lift out clutch master cylinder assembly.
10.Remove 6 screws, remove pedal box top cover
and discard gasket.
11.Remove nut securing push rod to clutch pedal
trunnion.
12.Remove 2 bolts and remove clutch master
cylinder from pedal bracket.
13.Remove clutch pedal sensor and pipe union
from master cylinder and discard sealing
washers.Refit
14.Clean sensor and pipe union.
15.Fit clutch pedal sensor and pipe to master
cylinder using new sealing washers.
16.Position master cylinder to pedal bracket and
align push rod to pedal trunnion.
17.Fit bolts and nuts and secure master cylinder to
pedal bracket.
18.Fit nut securing push rod to clutch pedal trunnion
but do not tighten nut at this stage.
19.Move brake master cylinder aside and position
clutch master cylinder assembly.
20.Clean clutch pipe union.
21.Align pipe and tighten union.
22.Connect multiplug to clutch pedal sensor.
23.Tighten bolts securing clutch pedal and brake
pedal brackets to body.
24.Fit clutch pedal rubber.
25.Position closing panel and tighten screws to
lower’A’post.
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MANUAL GEARBOX
7
REPAIR GEARBOX
Service repair no - 37.20.02.99
Remove
1.Disconnect battery negative lead.
2.Remove gear lever and transfer gearbox lever
knobs.
3.Remove gearbox tunnel carpet.
4.Remove gear lever cover.
5.Remove nut and washer securing gear lever to
lower splined lever.
6.Mark gear lever spline setting to lower lever and
remove lever.
7.Release and remove insulation pad from tunnel.
8.Remove trim stud and lift up handbrake gaiter for
access to clevis pin.
9.Remove split pin, clevis pin, washer and
disconnect cable from handbrake lever; discard
split pin.
10.Remove 2 bolts securing hand-brake lever to
body, disconnect Lucar and remove lever.
11.Remove 2 screws securing relay panel and
collect 2 spacers.
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MANUAL GEARBOX
9
REPAIR
26.Remove 4 nuts securing front propeller shaft to
transfer gearbox, release propeller shaft from
output drive flange.
27.Remove 4 nuts, release rear propeller shaft from
brake drum.
28.Remove 2 bolts securing clutch slave cylinder,
release slave cylinder and position aside.
29.Fit support plateLRT-99-007to gearbox jack.
30.Position gearbox jack and support plate to
gearbox and secure with 3 bolts.
31.Support the weight of gearbox.
32.Remove 4 nuts securing LH and RH mountings
to chassis and transfer gearbox mounting
brackets.
33.Remove bolts securing mountings to gearbox,
raise gearbox and remove both mountings and
heat shield from LH mounting and brackets.
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37MANUAL GEARBOX
10
REPAIR
34.Pull handbrake cable through heel board.
35.Disconnect multiplug from speed sensor and
release harness from clip on transfer gearbox.
36.Remove retaining nut and release battery earth
lead from transfer gearbox.
37.Release body harness clips from bracket on top
of transfer gearbox.
38.Lower gearbox jack sufficiently to allow transfer
gearbox lever to clear tunnel.
39.Disconnect 2 Lucars from differential lock switch,
multiplug from reverse light switch and multiplug
from low ratio detect switch - if fitted and release
multiplug from bracket.
40.Remove bolt and release earth leads from RH
side of transfer gearbox.
41.Support the weight of the engine.
42.Remove 6 bolts securing clutch housing to
engine.
43.With assistance, remove gearbox from engine.
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