001 BMW 318i 1992 E36 Workshop Manual

2
.
On
MS
270R/A4S
310R
transmissions
:
Remove
front



5
.
Installation
is
reverse
of
Rmoval
.
and
rear
oil
sump
mounting
bolts
andremove
sumps



"
Always
replace
sea¡
for
drain
plug
and
al¡
gasket(s)
andand
sump
gaskets
.



O-rings
.

"
Clean
sump
and
sump
magnet(s)
using
a
lint-free

NOTE-



cloth
.

The
MS
270
R/A4S
310
R
transmissions
may
be
fitted



"
On
MS
270R/A4S310R
transmissions
:
Use
new
bolts

with
ASE
(inch)
bolts
.



at
sump
and
tighten
bolts
in-line,
one
after
other
(do
nottighten
bolts
in
a
cross-wise
pattern)
.

3
.
On
A5S
310Z
transmission
:
Remove
oil
sump
mount-



"
On
MS
310Z
transmission,
be
sureto
instan
rounded

ing
bolts
and
brackets,
noting
position
of
brackets
.
Re-



sump
clamping
brackets
at
corners
of
sump
.

move



"
Fill
transmission
with
approved
fluid
.
sump
and
sump
gasket
.



"
Check
fluid
level
as
described
under
ATF
leve¡,

4
.
Remove
ATF
otra¡ner
mount¡ng
screws
and
remove



checking
.

strainer
together
with
gasket
orO-ring
.
See
Fig
.
4
or

Fig
.
5
.

Fig
.
4
.



A4S
270R/A4S310R
fluid
strainer
mounting
boits
(arrows)
.

Fig
.
5
.



A5S
310Z
fluid
strainer
mounting
boits
(arrows)
.

0013230

AUTOMATIC
TRANSMISSION



240-
3

NOTE-

Use
newsump
bolts
purchased
from
BMW
.
Alternative-
ly,
clean
old
bolts
and
coat
with
Loctite®
thread
locking
compound
or
equivalent

Automatic
Transmission
Fluid
Capacity
(refill
only)

"
MS
270R/A4S310R
Removal
of
large
sump
only
........
3
.0liters
(3.2
qt)
Removal
ofboth
sumps
...........
5
.0liters(5
.3
qt)

"
MS
310Z
..
..
..................
3
.3liters
(3.5
qt)

Tightening
Torques

"
ATF
drain
plug
to
ATF
sump

MS
270R/A4S
310R
..........
..
25
Nm
(18
ft-Ib)

MS
310Z(M10
plug)
..........
..
16
Nm
(12
ft-Ib)

"
ATF
fill
plug
to
ATF
sump

MS
270R/A4S
310R
..........
..
33
Nm
(24
ft-Ib)

MS
310Z(M30
plug)
.....
..
..
:.
100
Nm
(74
ft-Ib)

"
ATF
strainer
to
valve
body

MS
270R/A4S
310R
.....
..
.
...
.
20
Nm
(15
ft-Ib)

MS
310Z
..............
..
.
...
..
6
Nm
(53
in-lb)

"
ATF
sump
to
transmission

MS
270R/A4S
310R
(M6)
.
..
.
..
...
12
Nm
(9
ft-¡b)

MS
310Z
(M6)
..........
..
.
..
...
6
Nm
(53
in-¡b)

TRANSMISSION
SERVICE

8
.
Disconnect
main
harness
connector
from
transmission

by
turning
its
bayonet
lock
ring
counterclockwise
.
Re-

move
wiring
harness
from
transmission
housing
.
See
Fig
.
8
.

Fig
.
8
.



Harness
connector
at
automatic
transmission
.

9
.
Where
applicable,
disconnect
harness
connector
from

speed
sensor
at
top
óf
transmission
.

10
.
Disconnect
transmission
cooler
line
clamps
from
en-

gine
.
Disconnect
lines
from
transmission
.

11
.
Support
transmission
with
transmission
jack
.
Remove

reinforcing
cross
brace
(if
applicable)
and
transmission

support
crossmember
.

NOTE-

Note
installation
positionof
support
crossmember
.

12
.
Remove
access
plug
in
cover
plate
on
right
side
of
en-

gine
block
and
remove
torqueconverter
bolts
.
Turn

crankshaft
to
access
boits
.
See
Fig
.
9
.

AUTOMATIC
TRANSMISSION



240-
5

Bellhousing
access
hole

Socket
wrench

Fig
.
9
.



Access
andremove
torque
converter
boits
through
hole
in
bellhousing
cover
.

0

A

fij
13
.
Remove
bellhousing-to-engine
mounting
bolts
.
See



Fig
.
10
.
Transmission-to-engine
Torx-head
mounting
bolts
.
Fig
.
10
.

0012592

TRANSMISSION
REMOVAL
AND
INSTALLATION

250-2



GEARSHIFT
LINKAGE

5
.
Remove
driveshaft
.
See260
Driveshaft
.



9
.
Release
gearshift
lever
retaining
ring
from
below
by

turningspecial
tool
90°(
1
/4
turn)
counterclockwise
.
See

6
.
Support
transmission
with
transmission
jack
.
Remove



Fig
.
4
.

crossmember
from
rear
of
transmission
.
See
Fig
.
2
.

Fig
.
2
.



Rear
transmission
crossmember
(arrow)
.

7
.
Lower
rear
of
transmission
to
access
gearshift
linkage
.

CAUTION-

Tilting
the
engine
to
lower
thetransmission
can
lead
to
damage
to
various
componente
due
to
lackof
clearance
.
-On
cars
with
AST
remove
throttle
body
.
-Remove
brake
fluid
reservoir
if
necessary
.

0013135

8
.
Working
below
transmission,
disconnect
shift
rod
from

gearshift
lever
.
Note
washers
on
either
side
of
shift
rod

end
.
See
Fig
.
3
.

v

clip

Shift
rod

Fig
.
3
.



Pull
off
shift
rod
retaining
clip
in
direction
of
arrow
(t)
;
disen-
gage
shift
rod
from
gearshift
lever
(2)
.

MANUAL
TRANSMISSION
GEARSHIFT

BMW
Tool
No
.
25
1
110
orequivalent

Fig
.
4
.



Shift
lever
retaining
ring
being
removed
using
BMW
special

tool
25
1
110
.

10
.
Raise
transmission
and
temporarily
instan
transmission

crossmember
.

11
.
Lower
vehicle
.
Working
from
inside
passengercom-

partment,
pull
upon
gearshift
lever
to
remove
it
togeth-

erwith
retaining
ring
and
rubber
grommet
.

Gearshift
lever,
installing

(manual
transmission)

6532

1
.
Instan
shift
lever,
aligninglocking
tabs
with
openings
in

shift
console
.
Press
down
on
retaining
ring
until
it
clicks
into
place
.
See
Fig
.
5
.

\
Retaining

Fig
.
5
.



Shift
lever
retaining
ring
.
Fit
plastic
tabs
into
slots
of
shift
con-
sole(arrows)
.

250-
6



GEARSHIFT
LINKAGE

Shift
interlock,
checking
function



1
.
Shift
selectorlever
to
park
(P)
position
and
turn
ignition

(automatic
transmission)

The
shift
interlock
usesa
cable
between
the
ignition
switch

and
the
shift
lever
to
lock
the
shift
lever
in
the
park
position

when
the
key
is
in
the
off
position
or
removed
.
This
feature

also
prevents
the
key
from
being
removed
from
the
ignition

lock
until
the
selectorlever
is
in
P
.
Fig
.
13
.

Fig
.
13
.
Shift
interlock
serves
two
safety
functions
:
1)
it
locks
shift
le-

ver
in
park
(P)
when
thekey
is
removed,
and
2)
it
prevents
re-
moval
of
key
untilshift
lever
is
moved
into
P
.

AUTOMATIC
TRANSMISSION
GEARSHIFT

Latchirig
Gate
0012714

key
to
the
"zero"
(off)
position
.

2
.
Remove
ignition
key
.
Check
that
selectorlever
cannot

be
shifted
out
of
P
position
.

NOTE-

"
lt
must
only
be
possible
to
remove
ignition
key
with

selector
lever
in
P
position
.

"
Shiftinterlock
cable
must
not
be
kinked
.

3
.
Turn
ignition
keyon
and
depressbrakepedal
.
Check

that
selectorlever
moves
freely
from
gear
to
gear
.

4
.
With
the
selectorlever
in
a
gear
position
other
than
P,

attempt
to
move
thekey
to
the
zero
position
.
The
key

shouldnot
go
into
the
zero
position
.

If
any
faults
arefound
check
the
cable
for
kinks
and
theca-

ble
attachment
points
for
damage
or
faults
.

DRIVESHAFT
SERVICE
.
...
.
.
.
...
.
..
.
.
.260-3

Driveshaft,
aligning
...............
.
...
.
.
260-3

Driveshaft,
removing
..............
.
.
.
.
.
.
260-4

260
Driveshaft

DRIVESHAFT
260-1

GENERAL
.
.
.
.
.
.
.
.....
.
.
.
........
.
...
.
260-1



Driveshaft,
installing
.
....
.
..
.
............
260-4

Flex-disc,
replacing
.....
.
.
.
.............
260-5
TROUBLESHOOTING
..
.
.
.
...
.
.........
260-1



Center
bearing
assembly,
replacing
.
......
.260-6
Frontcentering
guide,
replacing
..
.
.......
.
260-7

TABLE

a
.
Driveshaft
Troubleshooting
.
.
...
......
.
....
..
.
.
260-2

GENERAL



NOTE-

For
rear
drive
axlerepair
information,
see330
Rear
The
two-piece
driveshaft
is
joined
in
thecenter
by
a
sliding



Suspension
.
splined
coupling
.
This
coupling
compensates
for
fore
and
aft
movement
of
the
drive
line
.
The
driveshaft
ís
connected
to
the



Driveshaft
noise
or
vibration
may
be
caused
by
worn
or
transmission
bya
rubber
flex-disc
and
to
the
final
drive
by
a



damaged
components
.
Check
the
universal
joints
for
play
.
universal
joint
.
It
is
supported
in
the
micidle
by
a
center
support



With
the
driveshaft
installed,
pull
and
twist
the
driveshaft
while
bearing
.
The
bearing
is
mounted
in
rubber
to
isolate
vibration
.



watching
the
joint
.
The
BMW
specificationfor
play
is
very
See
Fig
.
1
.



small,
so
almost
any
noticeableplay
could
indicate
a
problem
.

TROU
BLESHOOTING



Check
thetorque
of
thefasteners
at
the
flange
connections
.
Check
therubber
of
the
flex-disc
and
center
bearing
for
dete

The
source
of
driveline
vibrations
and
noise
can
be
difficult



rioration
or
tearíng
and
check
for
preload
at
the
center
bearing

to
pinpoint
.
Engine,
transmission,
rear
axle,
or
wheel
vibra-



with
a
visual
inspection
.
Check
the
driveshaft
for
broken
or

tions
can
be
transmitted
through
the
driveshaft
to
the
car



missing
balance
weights
.
The
weights
are
welded
tabs
on
the

body
.
Noises
from
the
rear
of
thecar
may
be
caused
by
final



driveshaft
tubes
.
In
addition
to
inspecting
for
faulty
driveshaft

drive
problems,
orby
faulty
wheel
bearings,
drive
axies,
or



parts,
the
installed
angles
of
the
driveshaft
should
also
be

evenworn
or
improperly
inflatedtires
.



considered
.

Flex-disc

Center
universal
joint

Fig
.1
.



Driveshaft
and
final
drive
assembly
.

Rear
section
Splined
shaft



of
driveshaft
Center
support



`



Clamping
sleeve
bearíng
assembly

Differential
inputflange

0013110

TROUBLESHOOTING

260-
4
DRIVESHAFT

CAUTION
-

The
maximum
allowable
change
in
height
of
the

center
bearing
or
transmission
support
using

shims
is
3
mm
(0
.12
in
.)
.

Driveshaft,
removing

WARNING
-

"
Be
sure
the
wheels
are
off
the
ground
before
re-

moving
the
driveshaft
.
Set
the
parking
brake
be-

fore
removing
the
driveshaft
.

"
Once
the
driveshaft
has
been
removed,
the
vehi-
cle
can
roll
regardless
of
whether
the
transmis-
sion
isin
gear
or
not
.

"
The
driveshaft
fs
mounted
to
thetransmission
and
final
drive
with
self-locking
nuts
.
These
nuts

are
designed
to
be
used
only
once
and
should
be

replaced
during
reassembly
.

1.
Disconnect
oxygen
sensor
electrical
connectors
and
remove
complete
exhaustsystem
.
See
180
Exhaust

System
.

4
.
Remove
driveshaft
mounting
bolts
.
See
Fig
.
3
.
Discard

old
nuts
.

JG

Fig
.
3
.



Front
driveshaft
totransmission
mounting
bolt
being
re-
moved
.
Note
open-end
wrench
(arrow)
being
used
to
coun-
terhold
bolt
.

5
.
Loosen
threaded
clamping
sleeve
on
driveshaft
a
few
tucos
.
See
Fig
.
4
.

DRIVESHAFT
SERVICE

Fig
.
4
.



Threaded
clamping
sleeve
nut
being
loosened
.

0012037

6
.
Support
driveshaft
andremove
center
support
bearing

mounting
bolts
.

7
.
Remove
driveshaft
but
do
not
separate
two
halves
.
Pull

down
on
center
of
driveshaft
to
facilitate
removal
.

2
.
Remove
exhaust
heat
shield
and
heat
shieldcross-

member
.



NOTE-

If
driveshaft
halves
were
separate
and
not
match-

3
.
Matchmark
front
and
rear
driveshaft
connections
at



marked,
assemble
driveshaft
as
shown
in
drawing
.
If
a

transmissíon
and
final
drive
.



vibration
occurs,
disassemble
driveshaftand
rotate
one

section
180°
.
See
Fig
.
5
.

Driveshaft,
installing

Fig
.
5
.



Driveshaft
alignment
.
Centerlinesof
universal
joints
(arrows)

must
be
parallel
or
at
90°
to
each
other

1
.
Align
driveshaft
matchmarks
at
final
drive
and
then
at

transmission
flange
.
Start
attaching
nuts
.
Use
new
self-

locking
nuts
.

2
.
Position
center
support
bearing
and
start
attaching

nuts
.
Use
new
self-locking
nuts
.

3
.
Tighten
flangenuts
while
preventing
bolts
from
twisting

in
coupling
.
Tighten
final
drive
flange
first,
then
tighten

coupling
at
transmission
.

4
.
Preload
center
support
bearing
by
pushing
bearing
for-
ward4-6
mm
(0
.16-0
.24
in
.)
from
center
.
See
Fig
.
6
.
Tighten
attaching
bolts
.

260-
6
DRIVESHAFT

4
.
Insta¡¡
driveshaft
as
described
in
Driveshaft,
install-

ing
.

Tightening
Torques

"
Driveshaft
center
mount
to
body
.
...
21
Nm
(16
ft-Ib)

"
Driveshaft
clamping
sleeve
.....
...
10
Nm
(89
in-lb)

"
Driveshaft
to
final
drive
flange

With
CV
joint
(M8)
............
...
32
Nm
(23
ft-Ib)

Wth
U-joint
(M10
ribbed
nut)
......
.
80
Nm
(59
ft-Ib)

With
U-joint
(M10
compressed
nut)
.
.
60
Nm
(44
ft-Ib)

"
Flex-disc
to
driveshaft
or
transmission
flange

M10
(8
.8
grade)
.
...
.............
48
Nm
(35
ft-Ib)

M10
(10
.9
grade
.
...
.............
64
Nm
(47
ft-Ib)

M12
(8
.8
grade)
..
..
.............
81
Nm
(60
ft-Ib)

M12
(10
.9
grade)
.
..
............
100
Nm
(74
ft-Ib)

M12
(10
.9
grade)
(M3
models)
.....
115
Nm
(85
ft-Ib)

"
Transmission
crossmember

to
body
(M8)
......
...
.
..
........
21
Nm
(16
ft-Ib)

5
.
Remove
center
bearing
circlip
and
dust
guard
.
See
Fig
.

Center
bearing
assembly,
replacing



10
.
Remove
bearing
from
driveshaft
using
puller
.

To
replace
thecenter
bearing
assembly,
the
driveshaft

must
be
removed
from
thecar
.
The
center
bearing
assembly

consists
of
a
grooved
ball
bearing
in
a
rubber
mount
.
The

bearing
assembly
is
pressed
onto
the
front
section
of
the

driveshaft
and
securedby
a
circlip
.
See
Fig
.
8
.

Circlip

NOTE
-

Torque
only
the
nuts
while
holding
the
bolt
heads
.
Thís
will
prevent
damaging
or
fatiguing
the
rubber
.

Dust
cap

Fig
.
8
.



Exploded
view
of
driveshaft
support
bearing
assembly
.

1
.
Remove
driveshaft
.
See
Driveshaft,
removing
.

DRIVESHAFT
SERVICE

0012594

5333

Fig
.
9
.



Before
pulling
apart
driveshaft
sections,
make
matching
marks
as
shown
.

4
.
Inspect
condition
of
rubber
bushing
for
splined
cou-

pling
.
Replace
worn
or
damaged
parts
.

2
.
Make
matching
marks
on
front
and
rear
driveshaft
sec-



NOTE-

tions
.
See
Fig
.
9
.



Install
puller
so
that
it
pulls
on
inner
hub
of
bearing
.
Pulling
on
outer
ring
of
mount
may
tear
rubber,
and
en

3
.
Loosen
clamping
sleeve
fully
and
pull
driveshaft
sec-



tire
bearing
assembly
will
need
to
be
replaced
.

tions
apart
.
Remove
rubber
bushing,
washer,
and
clamping
sleeve
from
front
section
.

5334

Fig
.
10
.
Center
bearing
circlip
(arrow)
to
be
removed
.
Driveshafl
shown
installed
.

SUSPENSION,
STEERING
ANDBRAKES-GENERAL



300-1

300
Suspension,
Steering

and
Brakes-General

GENERAL
.....
.
....
.
.....
.
.
.
........
.300-1



M3
SUSPENSION
AND
BRAKES
.......
.
...
300-7

Front
Suspension
..........
.
.
.
...
.
.....
300-1

Steering
...
.
.
.
.
.
....
.
.
.
...
.
.
.
...
.
...
.
.
300-2



SUSPENSION
AND
STEERING

Rear
Suspension
....
.
.
.
...
.
.
.
...
.
.....
300-2



TROUBLESHOOTING
..
.
.
.
.............
300-7

Brakes
.
.
.
.
.
.
.
.
....
.
...........
.
.
.
.
.
.
300-2

Tires
and
wheeis
.
................
.
.
.
.
.
.
300-2



TABLE

a
.
AST
Indicator
Lamp
Function
..
..
.
..
.
.........
300-5

INTEGRATED
SYSTEMS
.........
.
.
.
.
.
.
300-2



b
.
Suspension
and
Steering
Troubleshooting
......
.300-8

Antilock
Brake
System
(ABS)
.......
.
.
.
.
.
.
300-2

Al¡
Season
Traction
(AST)
.........
.
.
.
.
.
.
300-4

GENERAL



Front
Suspension

This
section
covers
general
information
for
front
and
rear



The
lower
control
arms
connect
the
front
suspension
struts

suspension,
the
steering
system,
and
the
brakíng
and
traction



to
mounting
points
on
the
subframe
crossmember
and
the

control
systems
.



body
.
See
Fig
.
2
.

The
BMW
E36
suspension
and
steering
systems
are
engi-

neered
to
provide
a
compromise
between
taut,
responsive
handling
and
ride
comfort
.
Although
the
front
and
rear
suspen-
sion
assemblies
are
independent
subsystems,
they
work
to-

gether
to
achieve
BMW's
overall
combination
of
precise

handling
and
comfort
.
See
Fig
.
1
.

Fig
.
1
.



BMW
E36
front
and
rear
suspension
systems
.

Each
front
strut
assembly
includes
a
shock
absorber
car-

tridgeinside
the
tubular
strut
housing
and
a
large
coil
spring
.

The
upper
strut
mount
bearing
allows
the
strutto
turnwith
the

wheels
.
The
lower
end
of
the
strut,
which
includes
the
stub
axle
for
the
front
wheel,
connects
to
a
ball-joint
on
the
control
arm
.

0013098

GENERAL

300-2



SUSPENSION,
STEERING
AND
BRAKES-GENERAL

Steering

INTEGRATED
SYSTEMS

The
steering
linkage
connects
the
rack-and-pinion
unit
through
tie
rodsto
the
steering
arms
.
The
tie
rod
ends
allow
the
wheels
to
pivot
and
react
to
suspension
travel
.

Rear
Suspension

The
rear
axle
carrier
is
the
main
mounting
point
for
the
final

drive
housing
and
the
rear
suspension
components
.

Trailing
arms
locatethe
rear
wheels
and
anchorthe
springs,

shocks
and
stabilizer
bar
.
Driveaxies
with
constant-velocity

(CV)
joints
at
both
ends
transfer
power
from
the
differential
to

the
road
wheels
.
The
differential
is
mounted
to
the
rearaxle

carrier
through
rubber
mountsand
bushings
to
hele
isolate

drivetrain
noise
and
vibration
.

Brakes

E36
cars
areequipped
with
power
disc
brakes
with
an
inte-
gral
antilock
brakes
(ABS)
.
The
parking
brake
is
a
dual-drum

system
integrated
with
the
rear
brake
rotors
.
See
Fig
.
3
.

Power
assist
is
provided
by
a
vacuum
booster
when
the
en-

gine
is
running
.
The
brakepedal
pushrod
is
connected
directly

to
the
master
cylinder,
so
failure
of
the
vacuum
booster
does

not
normally
result
in
total
brake
failure
.

0012124



Each
disc
brakeuses
a
caliper
with
a
single
hydraulic
cylin-
Fig
.
2
.



Front
suspension
control
arm
(arrow)
.



der
.
Brake
pads
in
the
left
front
and
right
rear
contain
wear

sensors
.
When
the
padsneed
replacement,the
sensors
illu-
The
front
suspension
is
designed
with
minimum
positive



minate
a
light
on
the
dashboard
.
steering
offset
.
This
geometry
contributes
to
stability
when

traction
is
unequalfrom
side
to
side
.
Suspension
travel
is
lim-



Tires
and
Wheels
ited
by
rubber
bump
stops
.

The
three
point
mounting
of
each
L-shaped
control
arm
ere-



Tiresize
is
critica¡
to
the
proper
operatíon
of
the
E36
ABS
or

cisely
controls
the
front-to-rear
and
side-to-side
position
of
the



ABS/AST
system
.
Severa¡
different
styles
of
wheels,
in
15,16

strut,
while
the
flexibility
of
the
joints
and
mounts
alsoallows



and
17
inch
diameters,
are
available
from
an
authorized
BMW

the
movement
necessary
for
suspension
travel
.
The
control



dealer
.

arm
mounting
points
are
designed
with
anti-dive
geometry
.

The
suspension
reduces
the
normaltendency
for
the
front
of



NOTE-
the
vehicle
to
dive
under
hard
braking
.



Aftermarket
wheelsshould
be
selected
wlth
care
.
Im-
properly
fitted
wheels
can
contact
anddamage
sus

Control
arm
position
is
fixed,
with
no
adjustment
provisions



pension,
brakeorbodycomponentsandmayadversely

on
the
control
arms
for
alter¡ng
front
wheel
al
ignment
.
A
stabi-



affect
vehicle
stability
.

lizer
bar
mounted
to
both
control
arms
heles
to
reduce
body
rol¡
whencomering
.



INTEGRATED
SYSTEMS

Antilock
Brake
System
(ABS)
is
standard
on
all
E36
cars
.

The
variable-assist
power
steering
system
consists
of
an



Standard
on
some
models
and
installed
as
optional
equipment
on

engine-driven
hydraulic
pump,
a
rack-and-pinion
type
steer-



others,
is
All
Season
Traction
(AST)
.

ing
gear,
and
connecting
linkage
to
the
road
wheels
.
TheE36
utilizes
an
engine-speed
dependent
variable
effort
steering



Antilock
Brake
System
(ABS)

system
.
At
low
speeds,
maximum
power
assist
is
provided
to
ease
parking
and
city
driving
.
Athigh
speeds,
assist
is
re-



The
electronically-controlled
ABS
maintains
vehícle
stabili
duced
to
ensure
stability
.



ty
and
control
during
emergency
braking
by
preventing
wheel
lock-up
.
ABS
provides
optimum
deceleration
and
stability
dur-

Wheel
brake
caliper

Electronic
control
module
Fig
.
4
.



Schematic
representation
of
ABS
.

SUSPENSION,
STEERING
ANDBRAKES-GENERAL



300-3

Fig
.
3
.



Schematic
view
ofdual
circuit
brakes
with
4-channel
ABS
.

ing
adverse
conditions
.
It
automatically
adjusts
brake
system
hydraulic
pressure
at
each
wheel
to
prevent
wheel
lock-up
.

The
system's
main
components
arethe
wheel
speed
(pulse)
sensors,
the
ABS
control
module,
and
the
hydraulic

control
unit
.
See
Fig
.
4
.

Warning
lamp

u
Master

Whee

_

l
speed



I-lydraulic



cylinder

sensor



control
unit



0012135

UNI

The
wheel
speed
sensors
continuously
send
wheel
speed
signals
to
the
control
module
.
See
Fig
.
5
.
The
control
module
compares
these
signals
to
determine,
in
fractions
of
a
second,
whether
any
of
the
wheels
areabout
to
lock
.
If
any
wheel
is
nearing
a
lock-up
condition,
the
module
signals
the
hydraulic
unit
to
maintain
or
reduce
pressure
at
the
appropriatewheel(s)
.
Pressure
is
modulated
by
electrically-operated
sole-

noid
valves
in
the
hydraulic
unit
.

Fig
.
5
.



ABS
wheelspeed
sensor
.

0006563

INTEGRATED
SYSTEMS