1998 BMW 328i hydraulic system

210-2
CLUTCH

Clutch
hydraulic
system,

bleeding
and
flushing

If
the
clutch/brake
fluid
is
murky
or
muddy,
or
has
not
been

changed
within
the
last
two
years,
the
system
should
be

flushed
.
Flushing
the
old
fluid
from
the
clutch
lines
is
done
us-

ing
a
brake
system
pressure
bleeder
.

1
.
Remove
brake
fluíd
reservoir
cap
.
Usinga
clean
sy-

ringe,
remove
brake
fluid
from
reservoir
.
Refill
reservoir

with
clean
fluid
.

2
.
Attach
pressure
brake
bleeder
to
fluid
reservoír
.

CA
UTION-

Do
not
exceed
2
bar
(29
psi)
pressure
at
the
fluid
reservoir
when
bleeding
or
flushing
the
hydraulic
system
.

3
.
Connect
a
length
of
hose
from
clutch
slave
cylinder

bleeder
valve
lo
a
container
.
See
Fig
.
2
.

0012003
Fig
.
2
.



Clutch
slave
cylinder
bleeder
valve
on
left
side
of
transmission
(arrow)
.

4
.
Open
bleeder
valve
and
allow
brake
fluid
to
expel
until
clean
fluid
comes
out
free
of
air
bubbles
.

5
.
Close
bleeder
valve
and
disconnect
pressure
bleeding
equipment
from
fluid
reservoir
.
Hose
on
bleeder
valve
remainsconnected
.

6
.
Slowly
operate
clutch
pedal
about10
times
.
Fill
reser-
voir
with
clean
fluid
asnecessary
.

7
.
Unbolt
slavecylinder
from
transmission
.

8
.
Position
slave
cylinder
so
that
bleeder
valve
is
facing
up
(highest
point)
.

CLUTCH
HYDRAULICS

9
.
Open
bleeder
valve
and
slowly
push
slave
cylinder

pushrod
al¡
the
way
in
.
Close
bleeder
valve
and
slowly

release
pushrod
.
Repeat
procedure
until
fluid
runs
out

clear
and
without
bubbles
.

10
.
Disconnect
bleeder
hose
.
Instan
slavecylinder
lo
trans-

mission
.
Add
cleanbrake
fluid
to
reservoir
as
neces-

sary
.
Check
clutch
operation
.

Tightening
Torques

"
Clutch
slave
cylinder
to
transmission
................
..
22
Nm
(17
ft
lb)

Clutch
master
cylinder,
replacing

The
clutch
master
cylinder
is
mounted
to
the
pedal
assem-

bly,
directly
above
the
clutch
pedal
.
1
.
Disconnect
negative
(-)
cable
from
battery
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautionsgiven
at
the
front
of
this
manual
on
page
viii
.

2
.
Remove
brake
fluid
reservoir
cap
.
Usinga
clean
sy-

ringe,
remove
brake
fluid
from
reservoir
.

CA
UTION-

Brake
fluid
is
poisonous,
highly
corrosive
and
dan-gerous
to
the
environment
.
Wear
safety
glasses
and
rubbergloves
when
working
with
brake
fluid
.
Do
notsiphonbrake
fluid
with
your
mouth
.
Imme-
diately
clean
away
any
fluid
spilled
on
painted
sur-
faces
and
wash
with
water,
asbrake
fluid
will
remove
point
.

3
.
Disconnect
fluid
supply
hose
from
master
cylinder
.

Placea
pan
under
hose
to
catch
any
excess
fluid
.

4
.
Working
in
engine
compartment,
disconnect
fluid
line
fitting
frommaster
cylinder
.

5
.
Working
in
passenger
compartment,
remove
lower
in-
strument
panel
trim
above
pedal
cluster
.

6
.
Disconnect
clutch
pedal
from
clutch
master
cylinder
push
rod
by
removing
clevis
pin
locking
clip
and
slide
out
clevis
pin
.

7
.
Remove
master
cylinder
mounting
bolts
.
See
Fig
.
3
.

8
.
Installation
is
reverse
of
removal
.
Fill
fluid
reservoir
with
clean
fluid
.
Bleed
clutch
hydraulics
as
described
earlier
.

Connect
negative
cable
to
battery
last
.

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

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

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

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

320
Steering
and
Wheel
Alignment

GENERAL
...
.
.
.
...
.
....
.
.
.
.
.
.
.
.
.
...
.
.
320-1



Outer
tie
rod
end,
replacing
.
...
.
.
.
.
.
.
.
...
.
320-4

Tie
rod,
replacing
.
.
.
.
.
.
.
.......
.
.
.
.
.
...
.
320-5

STEERING
WHEEL



320-1

Steering
wheel,
removing
and
installing
.....
320-1



WHEEL
ALIGNMENT
.
.
.
.........
.
.....
.320-5

POWER
STEERING
SYSTEM
.
.
.
.
.
.
.....
320-2



Front
Toe-in
and
Toe
Difference
Angle
.
.
...
.
320-6

Power
steering
pump,



Rear
Toe-in
.
.
.
.
.
.
.
...
.
................
320-6
removing
and
installing
..
.
.
.
.
.
.
.
.
.
.....
320-2



Wheel
Alignment
Specifications
.....
.
......
320-6

Power
steering
system,
bleeding
and
filling
.
.
320-3

STEERING
GEAR
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.....
320-3

Steering
gear
rack,

removing
and
installing
.
...
.
..
.
..
..
..
.
..
.
320-3

GENERAL



STEERING
WHEEL

This
repair
group
covers
servicing
of
the
mechanical
and



The
BMW
E36
is
equipped
with
an
SRS
airbag
mounted
in

hydraulic
components
of
the
steering
system,
including
wheel



the
steering
wheel
.
Improper
handling
of
the
airbag
could
alignment
information
.



cause
serious
injury
.
The
airbag
is
an
explosivedevice
and

should
be
treated
with
extreme
caution
.
Always
follow
the
air-

The
variable-assist
power
steering
system
consistsof
an



bag
removal
procedure
as
outlined
in
721
Airbag
System

engine-driven
hydraulic
pump,
a
rack-and-pinion
steering



(SRS)
.

gear
assembly
with
an
integral
hydraulic
control
valve,
and

connecting
linkage
to
the
road
wheels
.



WARNING-

"
The
BMW
Supplemental
Restraint
System
(SRS)
At
lowspeeds,
maximum
power
assist
is
provided
to
ease



is
complex
and
special
precautions
must
be
ob-

parking
and
city
driving
.
At
high
speeds,
assist
is
reduced
to



served
when
servicing
.
Serious
injury
may
result

ensure
stability
.
The
power
steering
system
varies
assist



if
system
service
is
attempted
by
persons
unfa-

based
on
engine
speed
.



miliar
with
the
BMW
SRS
and
its
approved
ser-
vice
procedures
.
BMW
specifies
that
all

ING-



inspection
and
service
shouldbe
performed
by
WARN
an
authorized
BMW
dealer
.
"
Do
not
reuse
self-locking
nuts
.
They
are
de-signed
to
beused
only
once
and
may
failif
re-



"
BMW
Supplemental
Restraint
Systems
(SRS)
used
.
Always
replace
them
with
new
locking
nuts
.



are
equipped
with
a
back-up
power
supply
inside
the
SRS
control
module
.
A
10minute
waiting
"
Do
not
ínstall
bolts
and
nuts
coated
with
under-



shouldbe
observed
after
the
battery
cable
has
coating
wax,
as
correct
tightening
torque
cannot



been
disconnected
.
This
will
allow
the
reserve
be
assured
.
Always
clean
the
threads
with
sol-



power
supply
to
discharge
.
vent
before
installation,
or
install
new
parts
.

"
Do
not
attempt
to
weldor
straighten
any
steering
components
.
Always
replace
damaged
parts
.

NOTE-

For
information
on
steering
column-mounted
switches
and
the
ignition
lock,
see
612
Switches
and
Electrical
Accessories
.

STEERING
AND
WHEEL
ALIGNMENT



320-1

Caster
and
Camber
.
.
.
.
.
...........
.
....
320-5

TABLES

a
.
Front
Wheel
Alignment
Specifications
.
...
.......
320-6
b
.
Rear
Wheel
Alignment
Specifications
.
...
.......
320-6

Steering
wheel,
removing
and
installing

1
.
Center
steering
wheel
.
Make
sure
front
wheelsare

pointed
straight
ahead
.

2
.
Disconnect
negative
(-)
cable
from
battery
and
cover

terminal
with
insulating
material
.

CAUTION-
Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.

STEERING
WHEEL

Fig
.
3
.



Power
steering
pump
and
pulley
mounting
bolts
.

6
.
Installation
is
reverse
of
removal,
noting
the
following
:

"
Make
sure
al¡
thread
bores,
bolts,
nuts,
fluid
couplings

and
mating
surfaces
are
clean,
and
that
inside
surface

of
multi-ribbed-belt
is
free
of
grease
and
dirt
.

"
Use
new
sealing
washers
when
reattaching
power

steering
pressure
lines
.

"
Make
sure
hoses
have
adequate
clearance
from
chas-

sis
.
Do
not
over-torque
banjo
bolts
.

"
Fill
and
bleed
power
steering
system
as
described
be-

low
.

Power
steering
system,

bleeding
and
filling

1
.
Wíth
engine
off,
fill
power
steering
fluid
reservoir
with

clean
fluid
.
Fill
levelto
MAX
mark
on
dipstick
.

STEERING
AND
WHEEL
ALIGNMENT



320-
3

STEERING
GEAR
A
cutaway
of
the
power-assisted
rack-and-pinion
power

steering
gear
is
shown
in
Fig
.
4
.
The
rack
is
designed
to
be

maintenance
free
.

Pinion

Fig
.
4
.



Cutaway
of
rack-and-pinion
steering
gear
.

Tightening
Torques

"
Hydraulic
hoses
to
power
steering
pump



?he
steering
gear
and
linkage
require
no
maintenance
oth-

M10
banjo
bolt
.........
..
.
...
...
.
12
Nm
(9
ft-Ib)



er
than
alignment
and
a
periodic
inspection
for
worn
compo

M14
banjo
bolt
..............
..
..
35
Nm
(26
ft-Ib)



nents
.

M16
banjo
bolt
..............
...
.
40
Nm
(30
ft-Ib)

"
Power
steering
pump
to
bracket



Steering
gear
rack,
removing
and
installing
(self-locking
nuts)
.............
..
.
22
Nm
(16
ft-Ib)

"
Power
steering
pump
bracket
to
engine



1
.
Empty
power
steering
fluid
reservoir
using
clean
sy-

block
or
oil
pan
(self-locking
nuts)
...
22
Nm
(16
ft-lb)



ringe
.
Do
not
reuse
fluid
.

2
.
Disconnect
negative
(-)
cable
from
battery
and
cover

terminal
with
insulating
material
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery

disconnection
cautions
given
at
the
front
of
this

manual
on
page
viii
.

2
.
Start
engine
.
Slowly
turn
steering
wheelfrom
lock
to

lock
a
minimum
of
two
times
.



3
.
Carefully
remove
airbag
from
frontof
steering
wheel
.
See

721
Airbag
System
(SRS)
.
Store
airbag
unit
in
a
sale

3
.
Turn
engine
off
and
check
fluid
leve¡,
adding
fluid
if
nec-



place
.

essary
.
4
.
Make
sure
front
wheelsare
pointed
straight
ahead
.

5
.
Remove
outer
tie
rod
ball
joínt
nuts,
thenseparate
outer

tie
rod
ends
from
steering
arms
using
appropriate

press
tools
.

6
.
Disconnect
power
steering
hose
from
fluid
reservoir
.

STEERING
GEAR