1993 BMW M3 sensor

300-4



SUSPENSION,
STEERING
AND
BRAKES-GENERAL

Three-channel
ABS
ís
used
on
al[
E36
cars
equipped
with



Al¡
Season
Traction
(AST)
standard
ABS
.
Each
front
wheelhas
a
separate
solenoid

valve
to
modulate
hydraulic
pressure
to
that
brake
caliper
.



The
traction
control
system
works
in
conjunction
with
ABS
The
rear
wheels
are
modulated
asa
pair,
controlled
by
a
sin-



and
the
engine
management
system
to
enhance
vehicle
con
gle
solenoid
valve
.



trol
.
The
main
function
of
the
AST
system
is
to
maintain
the
rolling

contact
between
the
tires
and
the
road
surface
under
al¡
driving
E36
cars
equipped
with
ABS/AST
utilize
a
four
channel
sys-



conditions
.
This
is
achieved
through
exact
application
and
tem,
which
functionsexactly
as
the
three
channelsystem



management
of
braking
and
drivetrain
forces
.
above,except
that
the
rear
wheels
are
modulated
individually
.

IDLE
SPEED
CONTROL
VALVE

HROTTLE
PLATE

6
.

Í
III

i



ADS
ACTU
AT
OR

THROTTLE
PLATE
POSITION
SENSOR

DME

Fig
.
6
.
All
Season
Traction
(AS)
works
withother
drivetrain
systems
to
enhance
vehicle
control
.

INTEGRATED
SYSTEMS

The
throttle
control
system
used
in
AST
is
illustrated
in
Fig
.

MASS
AIR
FLOW
SENSOR

JADS
THROTTLE
PLATE
POSITION
SENSOR

0013006

300-6



SUSPENSION,
STEERING
AND
BRAKES-GENERAL

BATTE
RY

KL
30

ECM
MAIN
C~
RELAY



KL
15

DSC
SWITCH

LF1
;1~lZZ~



nSLn

l'
z
sJ



WHEEL

RF

c_
.

LR

r_
.
>
RR

ELECTRONIC
BRAKE
LIGHT
SWITCH

SPEED

SENSORS

Fig
.
7
.



Schematic
of
AII
Season
Traction
(AST)
system
.

INTEGRATED
SYSTEMS

EDC

POWER
SUPPLY



SOLENOID
RELAY
GROUND
CONTROL

POWER
SUPPLY
I'
1
ABS
PUMP

GROUND
CONTROLÍ
F



f
iJ
RELAY

INLET
(4X)
wxxuw
OUTLET
(4X)



-=-=--



AST
AST
INTAKE
IHYDRAULIC
-
=-

SWITCHING
=---

!
99001
!J

WHEEL
SPEED
X
4

DME
II

000001
-
f



1
UNIT

AGS

IKE
&
DMEI
PARK
BREVE

771
SWITCH

M
ALTERNATOR



AUXILIARY
THROTTLE

r
`



INDICATOR



POSITION
MOTOR
(ADS)

ABSPUMP



DIAGNOSIS

RELAY



lu~~~b

0013027

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-
8



FRONT
SUSPENSION

FRONT
WHEEL
BEARINGS

The
front
wheel
bearings
are
permanently
sealed
and
re-

quire
no
maintenance
.
The
bearing
is
integral
with
the
wheel

hub
and
pressed
onto
the
steering
arm
stub
axle
.

Special
press
tools
are
requiredto
replace
the
front
wheel

bearings
.
Read
the
procedure
through
before
beginning
the

job
.

Front
wheel
bearing,
replacing

1
.
Raise
car
and
remove
wheel
.

WARNING-

Make
sure
that
the
car
is
firmly
supportedon
jack

stands
designed
for
the
purpose
.
Place
the
jack

stands
beneatha
structural
chassis
point
.
Do
not

place
jack
stands
under
suspension
parts
.

2
.
Pry
off
dust
cap
from
centerof
wheel
hub
.
Bend
back

staked
part
of
wheel
hub
(axle)
collar
nut
.
See
Fig
.
13
.

Fig
.
13
.
Staked
part
of
wheel
hub
collar
nut
to
be
bent
back
(arrow)
.

3
.
Remount
wheel
and
lug
bolts
.

4
.
Lower
canto
ground
.
With
an
assistant
applying
brakes,

loosen
collar
nut
.
Do
not
remove
completely
.

NOTE-

The
wheel
hub
collar
nut
is
tightened
to
a
torque
of
290
Nm
(214
ft-Ib)
.
Make
sure
the
car
is
firmly
on
the
ground
.

FRONT
WHEEL
BEARINGS

6
.
Remove
ABS
wheel
speed
sensor
.
Refer
to
Fig
.
3
.

7
.
Remove
brake
caliper
assembly
and
brake
rotor
as
de-

scribed
in
340
Brakes
.
Leave
brakehose
connected
to

caliper
.
Suspend
caliper
assembly
from
chassis
using

stiff
wire
.

8
.
Remove
wheel
hub
collar
nut
.

9
.
Remove
wheel
hub
with
integral
wheel
bearing
from

steering
arm
using
a
puller
.
See
Fig
.
14
.

0011200

Fig
.
14
.
Wheel
hub
with
integral
wheel
bearing
being
removed
using
a

puller
.

NOTE-
If
bearing
inner
race
stays
on
steering
arm,
remove
splash
guard
and
usetwo
jaw
puller
to
remove
race
.

10
.
Insta¡¡
splash
guard
and
new
dust
shield
behind
bear-

ing
.
Press
new
wheel
hub/bearing
assembly
on
using

appropriate
press
tools
.

NOTE-

When
pressing
the
wheel
hublbearing
on,
apply
force
only
to
the
bearing
inner
race
.

11
.
Install
new
collar
nut
.
Do
not
tighten
nut
to
its
final

torque
atthis
time
.

"
Install
brake
rotor
and
brake
caliper
.
See
340
Brakes
.

"
Mount
wheel
and
lug
boits
.
Lower
canto
ground
to
gain

leverage
.

12
.
With
an
assistant
applying
brakes,
tighten
collar
nut

and
then
stake
nut
toaxle
.

5
.
Raise
car
and
remove
wheel
.



13
.
Raisecar
and
remove
wheel
.

Wheel
bearing

Fig
.
7
.



Rear
wheel
bearing
assembly
.

Circlip



Drive
flange



Collar
nut

0012152

Rear
wheel
bearing,
replacing

1
.
Raise
car
and
support
safely
.
Remove
rear
wheel
.

2
.
Remove
drive
axle
as
described
later
.



6
.
Remove
bearíng
retainer
circlip
from
trailing
arm
.

3
.
Remove
brake
caliper
assembly
and
rotor
as
described



7
.
Using
appropriate
press
tools,
pull
bearing
assembly

in
340
Brakes
.
Leave
brake
hose
connected
to
caliper
.



out
of
trailing
arm
bearing
housing
.

Suspend
caliper
assembly
from
chassís
using
stiff
wire
.

8
.
Inspect
bearing
housing
for
any
damage
or
contamina

4
.
Remove
ABS
pulse
sensor
.
See
Fig
.
8
.



tion
.
Clean
housing
bore
thoroughly
before
installing

new
bearing
.
Make
sure
al¡
thread
bores,
bolts,
nuts

and
mating
surfaces
are
clean

Fig
.
8
.



ABS
pulse
sensor
being
removed
.

5
.
Remove
drive
flange
from
bearing
assembly
.
See
Fig
.

9
.

NOTE-

If
the
inner
bearing
race
remains
attached
to
the
drive

flange,
use
BMW
special
tool
nos
.
007
500
and
33
1

312
or
equivalents
to
separate
inner
race
from
flange
.

REAR
SUSPENSION



330-
5

0013125

Fig
.
9
.



Drive
flange
being
removed
from
bearing
assembly
using
im-
pact
style
puller
.

9
.
Install
new
bearing
assembly
using
press
tools
.
Apply

force
only
to
outer
race
when
installing
bearing
.

WARNING
-

M3
installation
:
redsealing
ríng
on
rear
wheel
bear-

ing
must
face
outward
.
Otherwíse
ABS
will
not
func-
tion
.

10
.
Insta¡¡
new
circlip
.
The
old
circlip
should
never
be
re-

used
.

CAUTION-

Make
sure
that
the
bearing
is
pressed
in
far
enough
to
contact
the
shoulder
at
the
back
sideof
the
housing
and
that
the
circlip
is
fully
seated
in
its
groove
.

11
.
Draw
drive
flange
into
bearing
using
appropriate
press

tools
.
Support
bearing
inner
race
when
pressing
in

0013223



drive
flange
.

NOTE-

BMW
specifies
special
tools
to
pull
the
drive
fiange
through
the
wheel
bearing
into
position
.
If
using
alter-
native
tools,
be
sure
to
support
the
bearing
inner
race
when
pressing
orpulling
the
drive
flange
finto
place
.

REARWHEEL
BEARINGS

330-
1
0



REAR
SUSPENSION

Trailing
arm,
removing
and
installing

1
.
Raise
rear
end
of
car
and
remove
wheel
.

WARNING
-

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

2
.
Remove
drive
axle
as
described
earlier
.

3
.
Remove
brake
rotor
and
caliper
as
described
in
340

Brakes
.
Do
not
remove
brake
line
from
caliper
.
Hang

caliper
from
body
with
wire
.

4
.
Remove
parking
brakecable
frombrake
shoe
expand-

er
.
See
340
Brakes
.

5
.
Remove
rear
brake
line
bracket
from
trailing
arm
.
See

Fig
.
17
.

Fig
.
17
.
Brake
line
bracket
bolts
on
trailing
arm
(arrow)
.

WARNING
-

It
is
recommended
that
a
restraining
chain
be
in-
stalled
between
the
bottom
coil
of
the
coil
spring
and
the
upper
control
arm
to
retainthe
spring
in
case
of
accidentalrelease
.
Personal
injury
can
re-sult
if
the
compressed
coil
spring
is
not
released
slow1y
and
carefully
.

REAR
SUSPENSION
ARMS

6
.
Support
trailing
arm
from
below
with
a
transmission
jackorequivalent
.

7
.
Remove
shock
absorber
to
trailing
arm
bolt
.
See
Fig
.
18
.
Slowly
lower
suspension
until
coil
spring
can
be
safely
removed
.

0013220

Fig
.
18
.
Support
trailing
arm
before
removing
lower
shock
bolt
(ar-

row)
.

8
.
Unbolt
upper
and
lower
control
arms
from
trailing
arm,

as
described
later
.

9
.
Remove
ABS
wheel
speed
sensor
from
rear
wheel

bearing
housing
.
Unclip
sensor
wiríng
from
trailing
arm
.

If
removing
right
trailing
arm,
separate
brake
pad
wear

sensor
connector
.
See
Fig
.
19
.

0012104

Fig
.
19
.
Brake
pad
wear
sensor
and
ABS
wheel
speed
sensor
con-
nectors
(arrow)
.

10
.
Remove
three
bolts
holding
trailing
arm
front
bracket
to
body
.
See
Fig
.
20
.
Remove
trailing
arm
.

Brake
rotor,
removing
and
installing
.
.
.
.
.
.
.
.
340-7

MASTER
CYLINDER
............
.
.
.
.
.
.
.340-7

Master
cylinder,
removing
and
installing
.
...
.
340-7

GENERAL



TROUBLESHOOTING

WARNING
-

"
Although
semi-metallic
and
metallic
Brake
friction
materials
in
Brake
pads
or
shoes
no
longer
con-
tain
asbestos,
they
produce
dangerous
dust
.
"
Brake
fluid
is
poisonous,
highly
corrosive
and
dangerous
to
the
environment
Wear
safety
glasses
and
rubber
gloves
when
working
with
Brake
fluid
.
Do
not
siphonBrake
fluid
with
your
mouth
.
Immediately
clean
away
any
fluid
spilled
on
painted
surfaces
and
wash
with
water,
asBrake
fluid
will
remove
paint
.

"
Always
use
new
Brake
fluid
froma
fresh,
un-
opened
container
.
Brake
fluid
will
absorb
mois-
ture
from
the
air
.
This
canlead
to
corrosion
problems
in
the
brakingsystem,
and
will
also
low-
er
the
Brake
fluid's
boiling
point
.
Dispose
of
Brake
fluid
properly
.

"
Do
notreuse
self-locking
nuts,bolts
or
fasteners
.
They
are
designed
to
be
used
only
once
and
may
failif
reused
.
Always
replace
them
with
new
self-
locking
fasteners
.

BMW
E36
models
areequipped
with
vacuum
power-assist-

ed
four-wheel
disc
brakes
with
an
integral
Antilock
Brake
Sys-

tem
(ABS)
.
Single-pistoncalipers
act
on
solid
or
vented
front
rotors
and
solid
rear
rotors
.
A
brake
pad
wear
sensor
for
each

axle
indicates
when
brake
padsneed
replacement
.
The
dual

drum-type
parking
brakesystem
is
integrated
with
the
rear
brake
rotors
.

NOTE-

M3
models
havevented
directional
Brake
rotors
on
the
rearaxle
as
well
ason
the
front
.

340
Brakes

BRAKES
340-1

GENERAL
.
.
.
.
.
.
.........
.
.
.
..........
340-1



BRAKE
BOOSTER
.........
.
.
.
.
.
...
.
.
.
.
340-8

TROUBLESHOOTING
.......
.
......
.
...
340-1



Brake
booster,
removing
and
installing
....
.
.
340-8

PARKING
BRAKE
.
.....
.
...
.
.
.
.....
.
.
.
340-10
BLEEDING
BRAKES
.
.
.
.
.
.
.
.
..........
340-3



Parking
brake,adjusting
.
.
.
.
.
.
.
.
.
.
.....
.
340-10
Pressure
bleeding
brakes



Parking
brake
shoes,
removing
and
installing
.
340-11(except
cars
with
AST)
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.340-3



Parking
Brake
cable,
replacing
.
.
.
.
.
.
.
.
.
.
.
.
340-11

BRAKE
PADS,
CALIPERS,



ANTILOCK
BRAKE
SYSTEM
(ABS)
.
.
.
.340-11
AND
ROTORS
..........
.
.......
.
.
.
.
.
.
.
340-3



ABS
System
Inspection
.
...
.
.......
.
.
.
..
340-12
Brake
pads,
replacing
............
.
.
.
.
.
.
.
340-4
ABS
wheel
speed
sensors,
replacing
.
.
.
.
..
340-12
Brake
caliper,
removing
and
installing
.
..
..
.
340-6

TABLES

a
.
Brake
System
Troubleshooting
.....
...
.
.
.....
.340-2
b
.
Brake
Rotor
Reconditioning
Specifications
.
.....
.340-7

Brakeperformance
is
mainly
affected
by
three
things
:
the
leve¡
and
condition
of
the
brake
fluid,
the
system's
abilíty
to
create
and
maintain
hydraulic
pressure,
and
the
condition
of
the
friction
components
.

Air
in
the
Brake
fluid
will
make
the
Brake
pedal
feel
spongy

during
braking
or
will
increase
the
Brake
pedalforce
required

to
stop
.
Fluid
contaminated
by
moisture
or
dirt
can
corrode
the

system
.
Inspect
the
Brake
fluid
inside
the
reservoir
.
Ifit
is
dirty
or
murky,
or
is
over
a
year
old,
the
fluid
should
be
replaced
.

Visually
check
the
hydraulic
system
startingat
the
master

cylinder
.
To
check
the
function
of
the
master
cylinder
hold
the

brake
pedal
down
hard
with
the
engine
running
.
The
pedal

should
feelsolid
and
stay
solid
.
If
the
pedal
slowly
falls
to
the

floor,
either
the
master
cylinder
is
leaking
internally,
or
fluid
is
leaking
externally
.
If
no
leaks
canbe
found,
the
master
cylin-
der
is
faulty
and
should
be
replaced
.
Check
all
Brake
fluid
lines

and
couplings
for
leaks,
kinks,
chafing
and
corrosion
.

Check
the
Brake
booster
by
pumping
the
Brake
pedal
ap-

proximately
10
times
with
the
engine
off
.
Hold
the
pedal
down
and
start
the
engine
.
The
pedal
should
fa¡¡
slightly
.
If
not,
check

for
any
visiblefaults
before
suspecting
a
faulty
brake
booster
.

Check
for
strong
vacuum
at
the
vacuum
hose
fitting
at
the

booster,
and
check
the
non-retum
valve
for
one-way
flow
.

Worn
or
contaminated
brake
pads
will
cause
poor
braking

performance
.
Oil-contaminated
or
glazed
pads
will
cause

stopping
distances
to
increase
.
Inspect
the
rotors
for
glazing,

discoloration
and
scoring
.
Steering
wheel
vibration
while

braking
at
speed
is
often
caused
by
warped
rotors,
but
can
also
be
caused
byworn
suspension
components
.

TROUBLESHOOTING