electric system BMW 325i 1992 E36 Repair Manual

NOTE-

Some
cars
covered
by
this
manual
may
have
an
alter-
nate
cooling
fan
switchwith
switching
temperatures
of
176%190W
(80%88°C)
.
When
replacing
the
switch
check
theswitching
specifications,
whichshouldbe
stamped
on
the
switch
body
.

1
.
If
coolant
is
circulating
at
normal
operating
tempera-
ture,
but
auxiliary
cooling
fan
does
not
run,
disconnect
connector
from
radiator
temperature
switch
and
make
tests
listed
in
Table
c
.

Table
c
.
Auxiliary
Cooling
Fan
Temperature

Switch
Tests

Wires
jumpered



Test



Test
resuits
conditions

Black/green
(terminal2)
and



Ignition
ON



Fan
runs
on
brown
(terminal
1)



low
speed

Black/gray
(terminal
3)
and



Ignition
ON



Fan
runson
brown
(terminal



I
1)



high
speed
2
.
If
fan
runs
only
when
powered
directly
by
jumpered
connector
and
hot
coolant
is
circulating
through
radia-
tor,
radiator
temperature
switch
is
most
likelyfaulty
.
Use
a
new
sealing
ring
when
replacing
switch

Tightening
Torque

"
Temperature
switch
to
radiator
......
15
Nm
(11
ft-Ib)

3
.
If
auxiliary
fan
does
notrun
when
powered
directly,
check
for
battery
voltage
at
temperature
switch
connec-
tor
(black/green
wire)
with
ignition
on
.
If
battery
voltage
is
not
present,
check
fuses
.
See
610
Electrical
Com-
ponent
Locations
.

RADIATOR
AND
COOLING
SYSTEM



170-
5

~r~nmm
a
00
0

Fig
.
4
.



Auxiliary
radiator
cooling
fan
low
speed
relay
(1)
and
high
speed
relay
(2)
in
power
distribution
box
.
(Relay
locations
may
vary
.)

Auxiliary
Cooling
Fan
Circuit
Fuses



Fig
.
5
.
Auxiliary
radiator
fan
resistor
(arrow)
.
"
Fuse16
.
...................
..
..
...
...
.5
amp

"
Fuse
41
(ex
.
M44
w/man
.
trans)
.
..
.
..
.....
30
amp

"
Fuse
48
(M44
w/man
.
trans
.
only)
..
.
..
.....
40
amp



COOLING
SYSTEM
SERVICE

0013034

4
.
If
no
faults
are
found,
remove
low
speed
relay
and
turn



Coolant,draining
and
filling

ignition
ON
.
See
Fig
.
4
.



1
.
Remove
expansion
tank
cap
.
Set
temperature
controls
"
Check
for
power
at
terminal
30
and
terminal
86
of
relay



to
full
warm
.
socket
.

"
Reinstall
low
speed
relay
and
repeat
testat
high
speed



WARNING
-
relay
socket
.
Fix
any
wiring
faults
found
.



Allow
the
cooling
system
to
cool
before
openlng
or

On
early
productioncars
(up
to
9/92)
:
If
fan
operates
only
on



draining
the
cooling
system
.

high
speed
and
no
electrical
faults
have
been
foundup
to
this
point,
usean
ohmmeter
to
check
that
fan
resistor
is
not
electri-



2
.
Place
3
ra
allo

ug
.



beneath
radiator
drain
plug
and
re-

cally
open
.
Resistor
is
mounted
on
auxiliary
cooling
fan
housing



move
drain
plg
.
See
Fig
.
6
.

behind
front
grille
.
See
Fig
.
5
.
Wiring
diagrams
for
the
radiator

cooling
fan
canbefoundunder
Electrical
Wiring
Diagrams
.



3
.
Place
3-g



pail
beneath
rear
of
engine
blo
.
Loos-
en
and
re

mlon

ove
engine
blockcoolant
drain
plug
k
.

COOLING
SYSTEM
SERVICE

170-8



RADIATOR
AND
COOLING
SYSTEM

Electric
cooling
fan,
replacing

On
late
4-cylinder
models
(M44
engine)
with
manual
trans-
mission,
the
primary
cooling
fan
is
electrically
operated
and
is
mounted
on
the
engine
side
of
the
radiator
.

1
.
If
necessary,
remove
cover
from
top
of
radiator
.
See
Fig
.
10
.

0012505
Fig
.
10
.
Air
cover
in
back
of
radiator
.
Unclip
cover
from
fan
shroud
af-
ter
removing
mounting
screws
.

2
.
Disconnect
fan
harness
connector
at
bottom
left
of
ra-
diator
.

3
.
Remove
fan
shroud
mountingscrews
at
left
and
right
side
of
radiator
.
Lift
fan
assembly
straight
up
and
offra-
diator
.

4
.
Installation
is
reverse
of
removal
.
Be
sure
to
align
side
tabs
on
fan
housíng
with
retaining
tabs
on
radiator
when
reinstalling
fan
.

Auxiliary
cooling
fan,
replacing

The
auxiliary
electric
cooling
fan
is
mounted
behind
the
front
bumper,
in
front
of
the
A/C
condenser
.
There
aretwo
ver-
sions
of
auxiliary
fans
installed,
depending
on
model
and
en-
gine
installed
.

TType
1
(u
p
to
9192)

1
.
Remove
front
radiator
air
shroud
.
See
Fig
.
11
.

2
.
Remove
fan
mountingscrews
.
See
Fig
.
12
.

3
.
Tilt
fan
forward
.
Disconnect
electrical
harness
connec-
tor
before
lifting
fan
up
.

COOLING
SYSTEM
SERVICE

Fig
.
11
.
Front
radiator
air
shroud
fasteners
(arrows)
.

Fig
.
12
.
Version
1
auxiliary
fan
mountingscrews
(arrows)
.

NOTE
-

If
necessary,
remove
front
bumper
or
lowerengine
cov-
erto
access
electrical
harnessconnector
.

4
.
Installation
is
reverse
of
removal
.

l)
Type
2
(from
9192)
2
.
Remove
fan
mounting
screws
.
See
Fig
.
13
.

0013137

1.
Remove
front
bumper
and
radiator
grilles
.
See
510
Ex-
terior
Trim,
Bumpers
.

3
.
Angle
fan
up
and
forward,
disconnecting
electrical
har-
nessconnectorbehind
it
.
Remove
it
through
bumper
opening
.

170-10



RADIATOR
AND
COOLING
SYSTEM

Coolant
pump,
replacing

The
engine
coolant
pump
is
mounted
in
the
frontof
the
en-

gine
on
the
timing
cover
.
See
Fig
.
16
.

Fig
.
16
.
Coolant
pump
mounted
on
timing
cover
.

NOTE-

Onlyreplacement
coolant
pumps
with
metal
¡mpellers
should
be
installed
.
Pumps
with
plastic
impellers
should
not
be
used
.

1.
Drain
cooling
system
as
described
earlier
.

0013197

WARNING
-

Allow
cool¡ng
system
to
cool
before
open¡ngor
drain¡ng
system
.

2
.
Remove
primary
cooling
fan
shroud
and
cooling
fan
(belt-driven
or
electric)
as
described
earlier
.

Fig
.
17
.
Engine
drive
belt
tensioner
being
released
on
M44
engine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
counterciock-
wise
direction
(as
facing
engine)
and
slip
belt
off
pulleys
.

Fig
.
18
.
Drive
belt
tensioner
being
released
on
M52
engine
.
Pry
off
3
.
Disconnect
hoses
from
thermostat
housing
.
Unbolt



tensioner
cover
and
then
lever
tensioner
clockwise
(as
facing
thermostat
housing
from
front
of
cylinder
head
.



engine)torelease
belt
tension
.

4
.
Remove
coolant
pump
drive
belt
.
See
Fig
.
17
or
Fig
.
18
.

NOTE-

-
Mark
direction
of
drive
belt
rotation
if
reusing
belt
.



"
The
6-cylinder
coolant
pump
¡s
mounted
on
studs
and
retained
by
nuts
.
"
Severa¡
drive
belt
and
tensioner
configurations
havebeenused
in
E36
models
.
Refer
to
020
Maintenance
Program
and
640
Heating
and
Air
Conditioning
.

5
.
Remove
coolant
pump
pulley
from
pump
.

6
.
Remove
mounting
fasteners
from
pump
.

COOLING
SYSTEM
SERVICE

NOTE-

"
The
4-cylinder
coolant
pump
¡s
mounted
us¡ng
two
dif-
terent
length
bolts
.
Note
where
thelonger
bolt
fits
dur-
ing
disassembly
.

0011989

7
.
Insert
twoscrews
(M6)
in
tapped
bores
and
tighten
uni-
formly
until
pump
is
free
from
timing
chain
cover
.
See
Fig
.
19
.

Fig
.
19
.
Coolant
pump
being
removed
.
Thread
two
M6
bolts
(arrows)
in
evenly
to
withdraw
pump
.
(Thermostat
and
hoseshavebeen
removed
tor
visual
access
.)

8
.
Installation
is
reverse
of
removal
.

"
Be
sure
to
replace
O-ring
and
gaskets
.

"
Coat
O-ring
with
lubricant
during
installation
.

Tightening
Torque

"
Coolant
pump
to
timing
chaincover

M6
...
.
...................
..
.
.
10
Nm
(89
in-lb)

M8
.
..
.
....................
.
.
.
22
Nm
(17
ft-Ib)

"
Coolant
pump
pulley

to
coolant
pump
.................
10
Nm
(89
in-lb)

RADIATOR
SERVICE

Radiator,
removing
and
installing

1
.
Drain
radiator
as
described
earlier
.

WARNING
-

Allow
cooling
system
to
cool
before
opening
ordraining
system
.

2
.
Remove
primary
cooling
fan
(belt-driven
or
electric)
as

described
earlier
.

3
.
Disconnect
coolingfan
and
leve¡
sensor
harness
con-

nectors
from
bottom
of
radiator,
where
applicable

4
.
Disconnect
harness
connector
from
auxiliary
fandual

temperature
switch
.
See
Fig
.
20
.

5
.
Disconnect
all
coolant
hoses
from
radiator
.

RADIATOR
AND
COOLING
SYSTEM



170-11

0012500

Fig
.
20
.
Cooling
fan
dual
temperatura
switch
(arrow)
on
right
sido
of
radiator
.

6
.
Where
applicable,
disconnectautomatic
transmission
fluid
(ATF)
cooler
lines
from
radiator
.
See
Fig
.
21
.

Fig
.
21
.
Automatic
transmission
fluid
(ATF)
linos
at
radiator
.

7
.
Carefully
pryout
radiator
retaining
clips
from
top
of
ra-

diator
.
See
Fig
.
22
.

8
.
Pul¡
radiator
up
and
out
of
car
.

NOTE-

The
radiator
rests
ontwo
rubber
mounts
.
Check
that

the
mounts
do
not
stick
to
the
bottomof
the
radiator
.

RADIATOR
SERVICE

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
.

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

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

320-2



STEERING
AND
WHEEL
ALIGNMENT

3
.
Carefully
remove
airbag
from
front
of
steering
wheel
.

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

safe
place
.

WARNING-

Improper
handling
of
theaírbag
could
cause
seri-
ous
ínjury
.
Store
theaírbag
with
the
horn
pad
facing
up
.
If
stored
facing
down,
accidental
deployment
could
propel
it
vlolently
into
the
air,
causíng
ínjury
.

4
.
Remove
steering
wheel
center
bolt
.
Lightly
punch
mark

or
scribe
position
of
steering
wheel
to
steering
column

shaft
.
See
Fig
.
1
.

0012687
Fig
.
1
.
Steering
wheel
center
bolt
(arrow)
.



Power
steering
pump,

removing
and
installing

POWER
STEERING
SYSTEM

5
.
Unlock
steering
wheel
by
turning
ignition
key
on
.
Re-
move
steering
wheel
.

WARNING-

The
SRS
contact
reel
ís
mounted
to
the
rear
of
the
steering
wheel
hub
.
The
contact
reel
ís
a
wound
coil
ofwirethat
ensures
continuous
electrícal
contact
for
the
air
bag
unit
Once
the
steering
wheel
mounting
nut
or
bolt
is
removed
the
contact
reel
is
locked
in
the
center
position
and
its
position
must
not
be
al-
tered
.

6
.
Insta¡¡
steering
wheel
while
aligning
matching
marks
.
Make
sure
airbag
contact
ring
locking
pin
engages
cutout
in
contact
reel
.
Insta¡¡
steering
column
center
nut
.
Do
not
over-torque
.
See
Fig
.
2
.

7
.
The
remainder
ofinstallation
is
reverse
of
removal
.
Carefully
install
airbag
from
front
of
steering
wheel
.
See
721
Airbag
System
(SRS)
.

Tightening
Torque

"
Steering
wheel
to
steering
column
spindle
...
..
..
.
..........
63
Nm
(46
ft-Ib)

Fig
.
2
.



Insta¡¡
steering
wheel
so
that
locking
pin
in
column
aligns
with
cutout
in
contact
reel
(arrow)
.
Contact
reel
on
late
model
steering
wheel
may
vary
from
that
shown
.

POWER
STEERING
SYSTEM

Power
assist
is
províded
by
a
belt-driven
pump
on
the
lower

left
front
of
the
engine,
just
below
the
alternator
.
The
power

steering
fluid
resenroir
is
located
on
the
lower
left
front
of
the
engine
.

1
.
Empty
power
steering
fluid
reservoir
usingclean
sy-

ringe
.
Do
not
reuse
fluid
.

2
.
Raise
front
of
car
.

WARNING

Make
sure
thecar
is
firmly
supportedon
jack
stands
designed
for
the
purpose
.
Place
the
jack
stands
be-
neatha
structural
chassis
point
.
Do
not
place
jack
stands
undersuspension
parts
.

3
.
Remove
fluid
hoses
frbm
pump
.
Plug
openings
in
pump
and
in
hose
ends
.

4
.
Remove
drive
belt
from
power
steering
pump
.
See
020
Maintenance
Program
.

5
.
Remove
pump
mounting
bolts
and
remove
pump
.
See
Fig
.
3
.

6
.
Disconnect
ABS
electrical
connectors
.
Label
and
then

disconnect
brake
lines
from
hydraulic
brake
unit
.
Plug

openíngs
.
See
Fig
.
12
.

~
~
A
1/
B
'1v
C
~
F

lu
11
-ri
J
.

0013244
A
.
Right
front



F



Front
from
master
cylinder
B
.
Leftfront



R
.
Rear
from
master
cylinder
C
.
Rear

Fig
.
12
.
Brake
fluid
linesat
ABS
hydraulic
unit
.

WARNING
-

"
On
cars
with
All
Season
Traction
(AST),
special
BMW
service
equipment
is
required
to
properly
bleed
the
Antilock
Brake
System
(ABS)
.
Removal
of
the
ABS
hydraulic
unit
is
not
recommended
un-
less
this
equipment
is
available
.
For
safetyrea-
sons,
the
brake
system
on
cars
with
ABS
must

not
be
bled
using
the
procedures
described
inthis
repair
group
.

"
Do
not
mix
up
the
fluid
fines
at
the
ABS
hydraulic
unit
Label
all
connections
before
disconnecting
.

7
.
Remove
ABS
hydraulic
unit
from
engine
compartment
.

8
.
Working
inside
car,
remove
panel(s)
frombeneath

steering
column
to
access
pedal
assembly
.
See513
In-

terior
Trim
.

12
.
Make
sure
al¡
nuts,
fluid
couplings,
thread
bores
and

mating
surfaces
are
clean
.

BRAKES
340-
9

0011261

Fig
.
13
.
Brake
pedal
clevispin
and
retaining
clip
(A)
.
Brake
booster
mounting
nuts
shown
at
arrows
.

13
.
If
necessary,
mount
master
cylinder
to
vacuum
booster

using
a
new
O-ríng
and
newself-locking
nuts
.

CAUTION-

Do
not
over-torque
the
master
cylinder
mounting
bolts
.
This
could
damage
the
brake
booster
and
prevent
proper
vacuum
build-up
.

14
.
Installation
is
reverse
of
Rmoval
.

"
Bleed
brakes
as
described
earlier
.

"
Check
and,
if
necessary,
adjust
brake
light
switch

above
brake
pedal
.

Tightening
Torques

"
Brakemaster
cylinder
to

brake
booster
...........
.
..
..
...
26
Nm
(18
ft-Ib)

"
Brake
booster
to
bulkhead
.
.
..
..
...
22
Nm
(16
ft-Ib)

"
Brake
fluidline
to
master
cylinder
or

ABS
hydraulic
unit
.......
.
..
17-19
Nm
(13-14
ft-lb)
9
.
Remove
clip
and
clevis
pin
from
brake
booster
pushrod

and
disconnect
it
from
brakepedal
.
Remove
brake

booster
mounting
nuts
.
See
Fig
.
13
.
NOTE-

10
.
Working
in
engine
compartment,
remove
brake
booster



When
replacing
the
brake
booster
one-way
valve
or
together
with
master
cylinder
.



vacuum
hose,
install
the
valve
so
that
the
molded
arrow

is
pointing
toward
the
intake
manifold
.
Use
new
hose

11
.
If
booster
or
master
cylinder
O-ring
is
being
replaced,



clamps
.

disconnect
master
cylinder
from
brake
booster
.

BRAKE
BOOSTER

340-
1
2
BRAKES

ABS
is
self-tested
by
the
ABS
diagnostic
unit
each
time
the
car
is
started
.
Once
the
test
is
complete,
the
ABS
dashboard
light
tucos
off
.
If
the
light
remains
lit
or
comes
on
at
any
time
during
driving,
a
system
fault
has
occurred
and
ABS
is
elec-
tronically
disabled
.
The
conventional
braking
systemremains
fully
functioning
.

ABS
Inspection

A
visual
inspection
of
the
ABS
may
help
to
locate
system
faults
.
If
no
visual
faults
can
befound
and
the
ABS
light
re-
mains
on,
have
the
system
diagnosedbyan
authorized
BMW
dealer
.

Carefully
inspect
the
entire
ABS
wiring
harness,
particularly

the
pulse
sensorharnesses
and
connectors
near
each
wheel
.

Look
for
chafing
or
damage
due
to
incorrectly
routed
wires
.

Carefully
remove
the
wheelspeed
sensors
.
Clean
the
sen-



Fig
.
18
.
Front
ABS
pulse
sensor
mounting
bolt
(arrow)
.
sor
tips
.
Inspect
the
toothed
wheel
on
thewheel
hub
.
Check
for
missing,
clogged
or
corroded
teeth,
or
other
damage
that
could
alter
the
clearance
between
the
sensor
tip
and
the
toothed
wheel
.

NOTE-

If
a
toothed
ring
is
damaged,
the
entire
wheel
hub
mustbe
reptaced
.
See
310
Front
Suspension
or330
Rear
Suspension
.

ABS
wheel
speed
sensors,
replacing

1
.
Raise
applicable
end
of
car
.

WARNING
-

Make
sure
thecar
is
firmly
supportedon
jack
stands
designed
for
the
purpose
.
Place
the
jack
stands
be-
neath
a
structural
chassis
point
Do
not
place
jack
stands
under
suspension
parts
.

2
.
Unscrew
wheelspeed
sensor
mounting
bolt
.
Remove
sensor
from
its
housing
.
See
Fig
.
18
.
Remove
harnessfrom
retaining
mounts
.

3
.
Front
ABS
sensor
:
Working
in
front
wheel
housing,
dis-
connect
and
remove
sensor
.
See
Fig
.
19
.

4
.
Rear
ABS
sensor
:
Working
in
rear
wheel
housing,
dis-
connect
andremove
sensor
.

5
.
During
installation,
apply
thin
coat
of
Molykote
0
Long-
term
2
or
an
equivalent
grease
to
pulse
sensor
and
housing
.

ANTILOCK
BRAKE
SYSTEM
(ABS)

0012122
Fig
.
19
.
Front
ABS
wheel
speed
electrical
connector
(arrow)
in
wheel
well
.

6
.
Installation
is
reverse
of
removal
.