1997 BMW 318i air

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

increased
power
output
and
road-handling
demands
.

The
steering
geometry
is
modified
by
changing
the
cast-

er/camber
angles
slightly
.
This
is
accomplishedby
reposition-

ing
the
upper
strut
mounting
holes
in
the
frontstrut
towers
and

through
different
front
and
rear
control
arms
.

M3
Brake
System
Improvements

"
Vented
directionalfront
rotors
:
315
mm
dia
.
x
28
mm
thick
.

"
Vented
directional
rear

rotors
:
312
mm
dia
.
x20
mm
thick
.

"
Larger
brake
pads
and
calipers
.

"
Modified
Teves
ABS
system
.

SUSPENSION,
STEERING
AND
BRAKES-GENERAL



300-
7

M3
SUSPENSION
AND
BRAKES



NOTE-

M3
brake
rotors
are
directional,
having
a
different
part

TheE36
M3
was
introduced
in
late
1994
as
a
1995
model
.



number
for
each
side
.
Rotors
with
an
odd
part
number

The
design
of
the
M3
suspension,
steering
and
brakes
is
a



go
on
the
left
while
rotors
with
en
even
part
numbergo

modification
of
existing
E36
systems
which
accommodates



on
the
right
.

M3
Front
SuspensionImprovements

"
Reinforced
spring
plates,control
arms,
control
arm
bush-

ings,
steering
arms
.

"
Recalibrated
struts,
firmer
springs
.

"
Stiffer
stabilizerbar,
larger
stabilizer
bar
bushings
.

"
Front
stabilizer
linked
to
struts
.

M3
Wheels/Tires

"
Front
wheels
1992-1998
:.....
7
.5J
x
17
in
.
light
alloy

"
Rear
wheel
1992-1997
.......
7
.5J
x17
in
.
light
alloy

"
Rear
wheel
(option)
........
.8
.5
Jx17
in
.
light
alloy

"
Front
and
rear
tire

1992-1997
.............
.
.
.
...
...
235/40
x
17
in
.

"
Front
tire
1998
only
......
...
.
.
.
...
225/45
x
17
in
.

"
Rear
tire
1998
only
.......
.
.
.
...
...
245/40
x
17
in
.

CAUTION-

In
en
emergency,
an
M3
front
wheel/tire
assembly
may
be
mounted
on
the
rearaxle
.
However
a
rear
wheel/tire
assemblymust
not
be
mounted
on
the
front
axle
.

M3
RearSuspensionImprovements

"
Reinforced
trailing
arms
.

"
Recalibrated
shock
absorbers,
firmer
springs
.



SUSPENSION
AND
STEERING

TROUBLESHOOTING

Stable
handling
and
ride
comfort
both
depend
on
the
integ-

rity
of
the
suspension
and
steering
components
.
Any
symp-

tom
of
instability
or
imprecise
road
feel
may
be
caused
by

worn
or
damaged
suspension
components
.

When
troubleshooting
suspension
and
steering
problems,

also
consider
the
condition
of
tires,
wheels,
and
their
align-

ment
.
Tire
wear
and
incorrect
inflation
pressures
can
dramati-

cally
affect
handling
.
Subtie
irregularities
in
wheel
alignment

angles
also
affect
stabílity
.
Mixing
different
types
or
sizes
of

tires,
particularly
on
the
same
axle,
can
affect
alignment
and

may
unbalancea
car's
handling
.

Table
b
lists
the
symptoms
of
common
suspension
and

steering
problems
and
their
probable
causes,
and
suggests

corrective
actions
.
Bold
type
indicates
the
repair
groups

where
applicable
test
and
repair
procedures
can
befound
.

SUSPENSION
AND
STEERING
TROUBLESHOOTING

300-8



SUSPENSION,
STEERING
AND
BRAKES-GENERAL

Tableb
.
Suspension
and
Steering
Troubleshooting

Symptom



1



Probable
cause
Repairs
(Repair
Groups
shown
in
bold)

Car
pulís
to
one
side,
wanders



a
.
Incorrect
tire
pressure



a
.
Check
and
correct
tire
pressures
.
020
b
.
Incorrect
wheel
alignment



b
.
Check
and
adjust
wheel
alignment
.
320
c
.
Faulty
brakes
(pulls
only
when
braking)



I
c
.
Check
for
sticking/damaged
front
caliper
.
340

Steering
heavy,
poor
return-



a
.
Worn
upper
strut
bearing(s)



a
.
Replace
strut
bearings
.
310
to-center



b
.
Incorrect
tire
pressure



b
.
Check
and
correct
tire
pressures
.
020
c
.
Power
steering
system
faulty



c
.
Check
power
steering
fluid
level
.
Test
system
pressure
.
320

Front-end
or
rear-end
vibra-



a
.
Worn
strut
cartridgesor
shock
absorbers



a
.
Replace
strut
cartridges
.
310,
330
tion
or
shimmy



b
.
Worn
suspension
bushings
(control
arm
or
trail-



b
.
Replace
worn
bushings
.
310,
330
ing
arm)
c
.
Worn
front
suspension
ball
joints
(control
arm,



c
.
Replace
worn
ball
joints
.
310
steering
arm
orsteering
tie-rod
end)d
.
Unbalanced
or
bent
wheels/tires



d
.
Balance
tires
.
Check
tiresfor
uneven
wear
pat-
terns
.
Check
wheels
for
damage
.
e
.
Loose
wheel
lug
boits



e
.
Tighten
lug
boits
to
proper
torque
.

Poor
stability,
repeated
bounc-
I
a
.
Worn
strut
cartridgesor
shock
absorbers



I
a
.
Replace
strut
cartridges
.
310,
330
ing
after
bumps,
suspension
bottoms
outeasily

Suspension
noise
(especially



a
.
Worn
front
upper
strut
bearings



a
.
Replaceupper
strut
bearings
.
310
over
bumps)



b
.
Loose
front
strut
cartridge



b
.
Check/tighten
strut
cartridge
collar
nut
.
310
c
.
Worn
suspensionbushings
(control
arm
or
trail-



c
.
Replace
worn
bushings
.
310,
330
ing
arm)d
.
Worn
stabilizer
bar
rubber
mounts



d
.
Replace
stabilizer
bar
rubber
mounts
.
310,
330
e
.
Loose
suspension
crossmember



e
.
Check
crossmember
for
damage
.
Tighten
mounting
boits
.

Uneven
ride
height



a
.
Incorrect
coil
springs



a
.
Measure
ride
height
and
replacesprings
as
re-
quired
.
310,
330
b
.
Bent
or
damaged
suspension
components



b
.
Inspect,
repair/replace
asnecessary
.
310,
330
c
.
Sagging
coil
springs



c
.
Measure
ride
height
and
replace
springs
as
re-
quired
.
310,
330

Wheel
noise,
continuous



I
a
.
Worn
wheel
bearing



I
a
.
Replacewheel
bearing
.
310,
330
growling,
may
be
more
notíce-
able
when
turning

Steering
loose,
imprecise



a
.
Incorrect
tire
pressure



a
.
Check
and
correct
tire
pressures
.
020
-



b
.
Loose
steering
gearmounting
bolt(s)



b
.
Inspect
and
tighten
boits
.
320
c
.
Worn
tie
rodend(s)



c
.
Replace
tie
rod(s)
and
align
wheels
.
320
d
.
Faulty
front
wheel
bearing



d
.
Replace
wheel
bearing
.
310
e
.
Worn
or
damaged
steering
gear



e
.
Adjust
or
replace
steering
gear
.
320
f
.
Worn
tires



f
.
Replace
tires
.
010

SUSPENSION
AND
STEERING
TROUBLESHOOTING

GENERAL

310
Front
Suspension

GENERAL
..
.
.
.
.
.
.
.
.
.
.......
.
........
.
310-1



FRONT
WHEEL
BEARINGS
..
.
.
.
.......
310-8

SHOCK
ABSORBERS
AND
SPRINGS
..
.
310-2



Front
wheel
bearing,
replacing
...
.
.
.
.
.
.
.
...
310-8

Strut
assembly,
removing
and
installing
.....
310-2



STABILIZER
BAR
..........
.
.
.
.
.
.
.
.
.
.
.
.
310-9

Strut
assembly,
disassembling



Stabilizerbar,
removing
and
installing
.
.
.
.
...
310-9

and
assembling
.
.
.
...
.
.....
.
.........
310-4

Ride
Height
.
.
.
.
.
.
.
.
.
.
.
.
.....
.
........
.
310-4



SUBFRAME
CROSSMEMBER
.
.
.
.
.
.
.
.
.
.
.
310-9

Subframe
crossmember,
CONTROL
ARMS
.
.
...
.
.
.
.
.
.
.
...
.
.....
310-5



removing
and
installing
.....
.
.
.
.
.
.
.
.
.
...
310-9

Control
arm,
removing
and
installing
....



..
310-5
Outer
control
arm
ball
joint,
replacing



Table

exce
t
M3
models



310-6



a
.
Front
Ride
Height
Specifications
..
.
.....
..
.
..
..
310-5
Control
arm
bushing,
replacing
.
.
.
...
.
.....
310-7

The
E36
front
suspension
is
shown
in
Fig
.
1
.
For
a
general



Specialservice
tools
arerequired
for
most
of
the
work
de-

description
of
the
front
suspension
and
components,
see
300



scribed
in
this
repair
group
.
Read
the
procedures
through
be-

Suspension,
Steering
and
Brakes-General
.



fore
beginning
any
job
.

Stabilizer
bar

Power
steering

fluid
cooler

Control



Strut
assembly
arm

Tierod

Fig
.
1
.



BMW
E36
front
suspension
.
(M3
suspension
shown
.
Others
are
similar
.)

FRONT
SUSPENSION



310-1

Steering
arm
0012132

GENERAL

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
.

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
:

Fig
.
6
.



Ride
height
measurement
(A)
is
taken
from
centerof
wheel
archto
bottom
of
wheel
rim
.

Normal
loaded
position

"
Each
front
seat
...
...
.
..
..........
68Kg
(150
Ibs)

"
Rear
seat
(center)
...
.
.
...........
68Kg
(150
Ibs)

"
Trunk
..........
...
.
.
...........
.21
Kg
(46
lbs)

"
Fuel
tank
...
.
..
....
.
.
....................
.fuf

Tablea
.
Front
RideHeight
Specifications

318,323,325,
Wheel
size



M3
models
328
models

15
inch
std
.
suspension



576
mm
(22.67
in)



1555
mm
(21.85
in)
sport
suspension



~
561
mm
(22.09
in)



530
mm
(20
.87
in)

16
inch
std
.
suspension



589
mm
(23.19
in)



1570
mm
(22
.44
in)
sport
suspensíon



~
574
mm
(23.52
in)



545
mm
(21.46
in)

17
inch
std
.
suspension



604
mm
(23.77
in)



585
mm
(23
.03
in)
sport
suspension



~
589
mm
(23.19
in)



~
560
mm
(22
.05
in)

Maximum
variation
between
sides
:
10
mm
(0.4in)
Maximum
deviation
from
specifications
:
10
mm
(0
.4in)

FRONT
SUSPENSION



310-
5

CONTROL
ARMS

On
al¡
models
except
Mas,
theouter
mounting
bushing
and
theouter
ball
joint
on
the
control
arm
are
available
as
replace-

ment
parts
.
If
the
control
arm
center
ball
joint
is
worn,
the
com-

plete
control
arm
will
need
to
be
replaced
.
See
Fig
.
7
.

Fig
.
7
.



Control
arm
.
Outer
ball
joint
and
bushing
are
available
as
re-
placement
parts
(except
M3)
.
Center
ball
joint
is
integral
with
control
arm
.

Special
press
tools
are
requiredto
remove
the
control
arms

and
to
replace
the
control
arm
bushings
.
Read
the
procedure

through
before
beginning
the
job
.

Control
arm,
removing
and
installing

1
.
Raise
car
and
remove
wheel
.

WARNING-

Make
sure
that
thecar
is
firmly
supportedon
jack
standsdesigned
for
the
purpose
.
Place
the
jack
stands
beneath
a
structural
chassis
point
.
Do
not
place
jack
stands
undersuspension
parts
.

2
.
Remove
stabilizer
bar
link
mounting
nut
and
separate

link
from
control
arm
as
described
later
in
this
repair

group
.

NOTE-

On
M3
models,
the
stabilizer
bar
link
attaches
to
the

strut
.

CONTROL
ARMS

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
.