1993 BMW M3 lock

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

NOTE-

The
traction
control
system
referred
to
as
AST
(all
sea-
son
traction)
may
also
be
referred
to
as
ASC
(Automat-
ic
Stability
Control)
and
ASC+T
(Automatic
Stability
Control+Traction)
.

The
AST
system
improves
traction
by
electronically
apply-

ing
the
rear
brakes
when
therear
drive
wheels
are
spinning
at

a
faster
rate
than
the
front
wheels
.
The
combined
ABS/AST

control
module,
operating
through
the
ABS
hydraulic
control

unit,
modulates
braking
force
at
therear
wheels
.

In
addition,
AST
uses
retarded
ignition
timing
and
an
auxil-iary
engine
throttle
plate
to
reduceengine
torque
and
maintain

vehicle
stability
.

The
auxiliary
throttle
plate
is
held
open
by
spring
pressure
.

The
AST
system
actívates
the
auxiliary
throttie
position
motor

(ADS)
to
cose
the
AST
throttle
as
needed
.
This
reduces
the

volume
of
engine
intake
air
.
Due
to
the
throttle
closing
very
rapidly
during
AST
operationthe
driver
cannot
increase
theengine
power
output
regardless
of
how
far
theaccelerator
pedal
is
pushed
to
the
floor
.

The
auxiliary
throttle
plate
is
placed
ahead
of
the
conven-

tional
throttle
plate
in
the
throttle
body
.

Traction
control
also
comes
into
operationduringdecelera-
tion
.
Decelerating
on
snowy
or
icy
road
surfaces
can
lead
to
rear
wheel
slip
.
If
a
rear
wheel
startsto
drag
or
lock
up
when

the
throttle
is
closed
rapidly
orduringdownshifting,the
AST
system
can
limit
the
problem
by
advancing
the
ignition
timing
.

A
switch
on
the
center
console
is
used
to
togglethe
AST
on

or
off
.

The
AST
system
is
designed
to
be
maintenance
free
.
There

are
no
adjustments
that
can
be
made
.
Repair
and
trouble-
shooting
of
the
AST
system
requires
special
test
equipment

andknowledgeand
should
be
performed
only
by
an
autho-

rized
BMW
dealer
.
Table
a
lists
theconditions
indicated
by

the
AST
indicator
light
in
the
instrument
cluster

SUSPENSION,
STEERING
AND
BRAKES-GENERAL



300-5

Tablea
.
AST
Indicator
Lamp
Function

Indicator
lamp



1
Condition



1
Comment

Light
on



Normal
AST
start-



Automatic
AST
up



self-test

Light
off



AST
monitoring



Automatic
AST
op-
mode



eration

Press
AST
button,



AST
off
(disabled)



Rocking
the
car
tolight
comes
on



getout
of
snow
or
other
loose
surface
Driving
with
snow
chains

Press
AST
button
:



AST
monitoring



Automatic
AST
op-
light
goes
out



I
mode



eration

Light
flashes



AST
active
mode



I
Normal
AST
oper-
ation
as
it
controls
wheel
speed

Light
stays
on
af-



Defect
in
AST



Consult
BMW
ter
start
up
or



dealer
for
diagno-
comes
on
while



sis/repair
driving



(Vehicle
operation
remains
normal)

WARNING
-

Even
a
car
with
AST
is
subject
to
the
normal
physi-
cal
laws
.
Avoid
excessive
speeds
for
the
road
con-
ditions
encountered
.

CAUTION-
"
If
the
tires
on
the
carare
of
different
makes,
the
AST
system
may
over-react
.
Only
fit
tires
of
the
same
make
and
tread
pattem,

"In
adverse
conditions,
such
as
trying
to
rock
the
car
outof
deep
snow
or
another
soft
surface,
or
when
snow
chainsare
fitted,
it
is
advisable
to
switch
off
AST
and
allow
the
cars
driveline
to
op-
erate
conventionally
.

INTEGRATED
SYSTEMS

310-2



FRONT
SUSPENSION

WARNING-

"
Physical
safety
could
be
impaired
if
procedures
described
here
areundertaken
without
the
proper
service
tools
and
equipment
.
Be
sure
to
have
the
right
tools
onhand
before
beginning
any
job
.

"
Do
notreuse
self-locking
nuts
or
bolts
.
They
are
designed
to
beused
only
once
and
may
fail
if
re-
used
.
Always
replace
self-locking
fasteners
any
timethey
are
loosenedor
removed
.

"
Do
not
install
bolts
and
nuts
coated
with
under-
coating
wax,
as
the
correct
tightening
torque
can-
not
beassured
.
Always
clean
the
threads
with
solventbefore
installation,
or
install
new
parts
.

"
Do
not
attempt
to
weld
or
straighten
any
suspen-
sion
components
.
Replace
damaged
parts
.

SHOCK
ABSORBERS
AND
SPRINGS

The
complete
front
strut
assembly
is
shown
in
Fig
.
2
.
Most

strut
assembly
components
are
available
asreplacement

parts
.

NOTE-

Struts
andlor
springs
shouldalways
be
replaced
in
parts
.

Strut
assembly,
removing
and
installing

1
.
Raisecar
and
remove
front
wheel
.

WARNING-

Make
sure
that
the
car
is
firmly
supported
on
jack
standsdesigned
for
the
purpose
.
Place
the
jack
standsbeneath
a
structural
chassis
point
Do
not
place
jack
stands
under
suspension
parts
.

2
.
Unbolt
brake
caliper
assembly,
keepingbrake
hose
connected
.
Detach
brake
hose
from
strut
assembly
.

Suspend
brake
caliper
from
chassis
using
stiff
wire
.
Re-
move
brake
rotor
.
See
340
Brakes
.

SHOCKABSORBERS
AND
SPRINGS

0011191
Fig
.
2
.



Front
strut
assembly
with
steering
arm,
front
hub,
front
spring
and
strut
upper
mount
.

3
.
Remove
ABS
wheelspeed
sensor
.
See
Fig
.
3
.

4
.
Disconnect
ABS
sensor
wire
harness
and
brake
pad
wear
sensor
wire
harness
(left
side
only)
from
strut
housing
.

5
.
OnM3
modeis
:
Disconnect
stabilizer
bar
link
from
strut
.

Fig
.
3
.



ABS
wheel
speed
sensor
mounting
bolt
(arrow)
.

NOTE-

Note
flats
on
stabilizer
bar
linkball
joint
for
placement
of
open
end
wrench
.

CAUTION-
Do
not
remove
center
strut
retaining
nut
.

8
.
Lower
strut
assembly
from
car
.

NOTE-

Store
the
removed
strut
assembly
upríght
.
Do
not
allow
it
to
líe
horizontally
or
upside-down
for
any
lengthoftime
.
If
íncorrect
storage
has
occurred,
place
the
strut
assembly
upríght
wíth
the
rod
fully
extended
for
at
least
24
hours
.

0012117

FRONT
SUSPENSION



310-3

6
.
Unbolt
splash
shield
and
steering
arm
from
strut
.
Sus-



Fig
.
4
.



Strut
and
steering
arm
assembly
.
pend
steering
arm
assembly
from
chassis
using
stiff
wire
.
See
Fig
.
4
.

1
.
Nut



6
.
Bolt
2
.
Strut



7
.
Bolt
3
.
ABS
wheel
speed
sensor



8
.
Flat
washer
4
.
Cable
holder



9
.
Self-locking
nut
5
.
Steering
arm



10
.
Washer
11
.
Bolt

9
.
Installation
is
reverse
of
removal
.
Be
sure
to
use
new

CAUTION-



self-locking
nuts
and
bolts
.

The
steering
arm
ball
joint
can
be
damaged
if
the



"
Use
new
steering
arm
mounting
bolts,
or
clean
bolts
arm
is
allowed
to
hang
unsupported
.



and
use
Locktite
®
270
orequivalent
thread-locking
compound
.

7
.
Support
strut
assembly
from
below
.
From
above,
re-



"
On
M3
models
:
When
attaching
stabilizer
link
to
strut,

move
three
strut
mounting
nuts
on
strut
tower
.



use
a
thin
wrench
to
hold
flats
on
link
parallelto
strut
.
"
Have
car
professionally
aligned
When
job
is
complete
.

Tightening
Torques

"
Brake
caliper
to
steering
arm
......
110
Nm
(81
ft-lb)

"
Road
wheel
to
hub
.........
100±10
Nm
(74
t7
ft-Ib)

"
Stabilizer
bar
link
to
strut
(M3)
.....
.
59
Nm
(44
ft-lb)

"
Steering
arm
to
strut
housing

"
(encapsulated
bolts-always
replace)
107
Nm
(78
ft-lb)

"
Strut
assembly
to
strut
tower

(self-locking
nuts)
........
...
..
..
.
24
Nm
(16
ft-Ib)

SHOCK
ABSORBERS
AND
SPRINGS

310-
4



FRONT
SUSPENSION

Strut
assembly,

disassembling
and
assembling
-
Be
sure
upper
spring
pad
is
correctly
installed
to
upper

NOTE-



spring
plate
and
spring
end
is
correctly
seated
in
up-
Springs
andlor
struts
should
always
be
replaced
in



per
and
lower
spring
plates
.

pairs
.



"
Use
a
new
self-locking
top
(center)
nut
.
Tighten
nut
fui-
¡y
before
releasing
spring
compressor
.

Replacing
the
upper
strut
mount,
spring
and
strut
requires



"
Have
car
professionally
aligned
when
job
is
complete
.

that
the
strut
first
bedisassembled
.
For
a
guide
to
the
parts

during
strut
replacement,
see
Fig
.
5
.
Tightening
Torques

WARNING-



"
Upper
strut
mount
to
strut
shaft
(seif-locking
nut)

Do
not,attempt
to
disassemble
thestruts
without
a



shaft
with
external
hexagon
......
..
65
Nm
(48
ft-1b)

springcompressordesignedspecificallyforthisjob
.



shaft
with
interna¡
hexagon
.......
..
44
Nm
(32
ft-Ib)

"
Road
wheel
to
hub
........
.100±10
Nm
(74
±7
ft-lb)

1
.
Remove
strut
assembly
as
described
earlier
.
Place
in

secure
support
.
Ride
Height

2
.
Using
spring
compressor,
compress
spring
until
spring

force
onupper
mount
is
relieved
.



Ride
height
is
measured
from
the
lower
edge
of
the
wheel

arch
to
the
bottom
edge
of
the
wheel
rim
.
See
Fig
.
6
.

WARNING
-

Make
sure
the
spring
compressor
grabs
the
spring



lf
the
ride
height
is
outside
the
specification
listed,
new

fully
and
securely
before
compressing
it
.



springs
should
be
installed
.
Be
sure
to
have
theold
spring

code
number
on
hand
when
ordering
new
spring
.

3
.
Pry
protective
cover
off
top
ofstrut
assembly,
then
re-

move
top
(center)
nut
andwasher
whileholding
strut



NOTE-

shaftstationary



The
spring
part
number
is
stamped
near
the
end
of
the
spring
cofls
.

4
.
Remove
upper
strut
mount
and
related
components
.

5
.
Release
spring
compressor
carefully
and
evenly,
allow-

ing
spring
lo
expand
slowly

1
Self-locking
hex
nut



Absorber/

Flat
washer



bump
stop

Nut

Cover

Upper



~
strut
mount



Pin
Z



Piston
bellows

Flat
washer



r
i

t1



~



1
Upper
spring
plate

1



1



1

Upper
spring
pad



I



1
-



,



Lower
spring
pad

-
Í



0012136

Fig
.
5
.



Front
spring,
spring
plate
and
related
parts
.

SHOCKABSORBERS
AND
SPRINGS

6
.
Assembly
is
reverse
of
disassembly,
noting
the
follow-

ing
:

Table
a
lists
front
suspension
ride
height
specifications
.

These
specifications
apply
to
a
car
in
a
normally
loaded
posi-

tion
.
When
checking
ride
height
or
installing
suspension
com-

ponents
that
require
thecar
to
be
"normally
loaded,"load
the

car
as
follows
:

310-
6



FRONT
SUSPENSION

3
.
Working
at
steering
arm,
remove
control
arm
balljoint

nut
.
See
Fig
.
8
.
Press
ball
joint
out
ofsteering
arm
.

Fig
.
8
.



Control
arm
ball
joint
nut
at
steering
arm
(arrow)
.

4
.
Remove
control
arm
to
subframe
crossmember
ball
joint
nut
.
Separate
ball
joint
from
crossmember
.
Work-

ing
at
other
end
of
control
arm,
remove
bolts
attaching

control
arm
bushing
carrier
to
body
.
See
Fig
.
9
.

Fig
.
9
.



Control
arm
bushing
carrier
bolts
(arrows)
.

0012117
0011960

5
.
Installation
is
reverse
of
removal
.
Make
sure
al¡
thread
bores,
bolts,
nuts
and
mating
surfaces
are
clean
.
Use
new
self-locking
nutsor
bolts,
where
applicable
.

WARNING-
"
Do
not
reuse
self-locking
nuts
or
bolts
.
They
are
designed
to
be
used
only
once
and
may
failif
re-
used
.

"
Bolts
and
nuts
coated
with
a
focking
compound
from
the
factory
shouldnot
be
refnstalled
.
Always
replace`micro-encapsulated"
fasteners
such
as
the
steering
arm-to-strutbolts
.

CONTROL
ARMS

Tightening
Torques

"
Control
arm
balljoint
to

subframe
crossmember
.
..
...
...
.
.
85
Nm
(62
ft-Ib)

"
Control
arm'ball
joint
to
steering
arm
.
65
Nm
(48
ft-Ib)

"
Control
arm
bushing
carrier
to
body
.
.
47
Nm
(34
ft-Ib)

"
Stabilizer
bar
link
to
control
arm
(M8)
.
42
Nm
(31
ft-Ib)

"
Road
wheel
to
hub
.
...
...
.
.
100±10
Nm
(74±7
ft-Ib)

Outer
control
arm
ball
joint,
replacing

(except
M3
models)

On
all
models
except
Mas,
the
outer
balljoint
is
available
as

a
replacement
part
.
The
ball
joint
can
be
replaced
with
the

control
arm
installed
.

Special
tools
are
requiredto
replace
the
balljoínt
.
Read
the

procedure
through
before
beginning
thejob
.

1
.
Disconnect
stabilizer
bar
link
from
control
arm
asde-

scribed
later
in
this
repair
group
.

NOTE-
On
M3
models,
the
stabilizer
bar
link
attaches
to
the
strut
.
tt
fs
not
necessary
to
disconnect
the
stabilizer
bar
link
on
M3
models
for
thfs
repair
procedure
.

2
.
Loosen
nut
for
balljointuntil
it
contacts
steering
arm
.

3
.
Using
a
suitable
ball
joint
tool,
separate
joint
from
steer-

íng
arm
.
Remove
ball
joint
mounting
nut
and
pullball

joint
out
of
steering
arm
.

4
.
Mark
position
of
balljoint
guide
to
control
arm
.
See
Fig
.

10
.

0012718

Fig
.
10
.
Mark
installed
position
of
ball
joint
guide
to
control
arm
(sr-
row)
.

5
.
Move
suspension
strut
out
of
way
and
press
ball
joint
out
of
control
arm
.

6
.
Installation
is
reverse
of
removal
.

"
Make
sure
control
arm
ball
joint
taper
bore
is
clean
and
free
of
any
corrosion
.
"
Press
new
balljoint
into
position,
making
sure
to
align
balljoint
guide
with
mark
made
earlier
.
"
Verify
that
locking
clip
on
new
ball
joint
faces
towards
center
of
vehicle
.

Tightening
Torques

"
Control
arm
ball
jointto
steering
arm
.
65
Nm
(48
ft-Ib)
"
Stabilizer
bar
link
to
control
arm
(M8)
42
Nm
(31
ft-Ib)
"
Road
wheel
to
hub
.
...
...
.
.
100±10
Nm
(74t7
ft-lb)

Control
arm
bushing,
replacing

Control
arm
bushings
should
aiways
be
replaced
in
pairs
and
the
two
bushings
and
bushing
carriers
should
have
the
same
markings,
indicating
same
manufacturer
.

1
.
Raisecar
.

WARNING-
Make
sure
that
the
car
is
firmly
supportedonjackstandsdesigned
for
the
purpose
.
Place
the
jackstands
beneath
a
structural
chassis
point
.
Do
not
place
jack
stands
undersuspension
parts
.

2
.
Unbolt
control
arm
bushing
carrier
from
body
.

3
.
Mark
installed
position
of
bushing
to
control
arm
.
See
Fig
.
11
.

assembly
off
control
arm
.

lnl~

0012145

FRONT
SUSPENSION



310-
7

NOTE-

The
kerosene-like
special
lubricant
is
used
only
asan
aid
in
installing
the
bushing
to
the
control
arm
stub
.
Workmustbe
carried
out
in
as
short
a
time
as
possible
.
Within
30
minutes
the
control
arm
bushing
will
be
`glued"
in
position
on
the
control
arm
.

CAUTION-

BMW
part
numbers
areprovided
for
reference
only
and
are
subject
to
change
.
Always
rely
on
an
authorized
BMW
dealerparts
department
for
the
most
up-to-date
information
.

6
.
Press
new
rubber
control
arm
bushing
assembly
onto
the
end
of
control
arm
to
proper
depth
(as
marked)
.

NOTE-

Be
sure
toreinstall
the
bushing
carrier
to
the
control
arm
correctly
.
The
carrier
has
centering
bores
on
side
.
This
side
must
face
up
towards
body
.
See
Fig
.
12
.

Fig
.
12
.
Control
arm
bushing
carrier
centering
bores
must
face
up
.

7
.
Immediately
bolt
control
arm
bushing
carrier
to
body,
torque
boits
and
lower
car
to
ground
.

Tightening
Torques

"
Control
arm
bushing
carrier
to
body
.
.
47
Nm
(34
ft-ib)
Fig
.
11
.
Before
removingbushing
from
control
arm,
mark
installed
po-
sition
of
old
bushing
to
control
arm
.
Insta¡¡
new
bushing
in
same
position
.



8
.
With
car
lowered
to
ground
and
loaded
as
described
earlier,
bounce
suspensiona
few
times,
then
leave
car

4
.
Using
appropriate
press
tools,
pull
control
arm
bushing



undisturbed
for
a
minimum
of
30
minutes
.

CAUTION-

5
.
Coat
end
of
control
arm
with
BMW
special
lubricant



I
Failure
to
follow
the
above
procedure
may
impair

part
no
.
8122
9
407284
.



the
car's
handling
and
stability
.

CONTROLARMS