1994 BMW M3 oil pressure

130-
3
6



FUEL
INJECTION

Pin



1
Signal



1
Componentffunction



1
Signal

1



output



Ignition
coil
control,
cyl
.
2



Primary
signal,
ignition
coil
2

2



output



Ignition
coil
control,
cyl
.
4



Primary
signal,
ignitioncoil
4

3



output



Ignition
coil
control,
cyl
.
6



Primary
signal,
ignition
coil
6
4
ground
Ground



Ground

5



output



Fuel
injectorcontrol,
cyl
.
2



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
2
6



output



Fuel
injectorcontrol,
cyl
.
1



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
1

7



output



Mass
air
flow
meter



Mass
air
meter
signal

8



input



Mass
air
flow
meter



Mass
air
meter
signal

9



output



Instrument
cluster



Fuel
consumption
signal

10



output



Engine
coolant
temperature
(ECT)
sensor



ECT
signal

11



output



Fueltankpressure
sensor



Fueltankpressure
sensor
control

12



input



Throttleposition
sensor
(TPS)



Throttleposition
signal

13
-

14



input



Intake
air
temperature
(IAT)
sensor



Intake
air
temperature
signal

15



Traction
control



AST
module

16



input



Automatic
climate
control



Automatic
climate
control

17

18



input



Electronic
immobilizer
control
(EWS
II)



Electronic
immobilizer
control
(EWS
II)
module

19



Automatic
climate
control



Automatic
climate
control

20



-



Instrument
cluster



Instrument
cluster

21



output



Camshaft
actuator
(VANOS
solenoid)
control



Camshaft
actuator
(VANOS
solenoid),
switched
ground

22



output



Fuel
injectorcontrol,
cyl
.
3



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
3

23



Fuel
injectorcontrol,
cyl
.
6



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
6

24



Fuel
injectorcontrol,
cyl
.
4



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
4

25



output



Oxygen
sensor
heater
control



Oxygen
sensor
heater
ground

26



input



Power
supply
(terminal
30)



Battery
voltage(B+)
at
all
times

27



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(see
also
pin
53)

28
ground
Ground



Ground
29



output



Ignition
coil
control,
cyl
.
1



Primary
signal,
ignition
coíl
1

30



output



Ignition
coil
control,
cyl
.
3



Primary
signal,
ignition
coil
3

31



output



Ignition
coil
control,
cyl
.
5



Primary
signal,
ignition
coil
5

32
ground
Ground



Ground
33



output



Fuel
injector
control,
cyl
.
5



Pulsedground
(injection
pulsewidth
in
ms)
cyl
.
5

34
ground
Ground



Ground
35



output



Secondary
air
injection



Secondary
air
injection
pump
relay
control

36



output



Engine
speed
output



Engine
speed
signal

37
-

38



ground



Knock
sensor



Shielding
for
knock
sensors

39



output



Intake
air
temperature
sensor
(IAT
Sensor)



Voltagesupply
to
IAT
sensor
and
ECT
sensorEngine
coolant
temperature
(ECT)
sensor

40



output



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

41



ground



Camshaft
position
(CMP)
sensor



Shielding
for
CMP
sensor

42



output



Throttle
position
sensor
(TPS)



TPS
ground

43



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

44



output



Throttle
position
sensor
(TPS)



Voltagesupply
to
TPS
(5
VDC)

45



Traction
control



AST
module
46



-



Instrument
cluster



Instrument
cluster

ECM
PIN
ASSIGNMENTS

Table
I.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1

170-2



RADIATOR
AND
COOLING
SYSTEM

Cooling
Fans



TROUBLESHOOTING

Belt-driven
coolingfan
.
The
primary
cooling
fan
is
belt-

driven
.
It
is
mounted
to
the
frontof
the
coolant
pump
through
a

fan
clutch
.
The
fan
clutch
is
a
viscous
fluid
coupling
that
con-

trols
the
speed
of
thefan
based
on
engine
compartment
tem-

perature
.

Electric
cooling
fan
.
Models
with
M44
engine
and
stan-

dard
transmission
substitute
an
electric
fan
for
the
belt-driven

viscous
fan
.
This
is
attached
to
the
rear
of
the
radiator
and

controlledvia
the
DME
5
.2
engine
management
system
.

NOTE-

The
electric
cooling
fan
in
these
models
is
activated
by
the
engine
control
module
(ECM)
.

Auxiliary
coolingfan
.
In
al¡
models
a
two-speed
electric

auxiliary
cooling
fan
is
mounted
behind
the
front
grill
and
in

front
of
the
radiator
.
This
fan
is
primarily
used
for
the
A/C
sys-

tem,
but
also
operates
when
the
coolant
temperature
ex-

ceeds
a
predetermined
leve¡
.

Warnings
and
Cautions

The
following
warnings
and
Cautions
should
beobserved

when
working
on
the
cooling
system
.

WARNING
-

"
Atnormal
operating
temperature
the
cooling
sys-
tem
is
pressurized
.
Allow
the
system
to
cool
as
long
as
possible
before
opening-a
minimum
of
an
hour-then
release
the
cap
slowly
to
allow
sale
release
of
pressure
.

"
Releasing
the
cooling
system
pressure
lowers
the
coolants
boiling
point
and
the
coolant
may
boíl
suddenly
.
Use
heavy
gloves
and
wear
eye
and
laceprotection
to
guard
against
scalding
.

"
Use
extreme
care
when
draining
and
disposing
of
engine
coolant
.
Coolant
is
poisonous
and
lethal
to
humans
and
pets
.
Pets
are
attracted
to
coolant
because
of
its
sweet
smell
and
taste
.
Consult
a
veterinarian
immediately
if
coolant
is
ingested
byan
animal
.

CAUTION-

"
Avoidadding
cold
water
to
the
coolant
while
the
engine
is
hot
or
overheated
.
If
it
is
necessary
to
add
coolant
to
ahot
system,
do
so
only
with
the
engine
running
and
coolant
pump
tuming
.

"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.

TROUBLESHOOTING

Most
cooling
system
faults
can
be
grouped
into
one
of
three

categories
:

"
Cooling
system
leaks

"
Poor
coolant
circulation

"
Radiator
cooling
fan
faults

When
investigating
the
cause
of
overheating
or
coolant

loss,
begin
with
a
visual
inspection
.
Be
sure
to
check
the
con-

dition
and
tension
of
the
coolant
pump
drive
belt
.
Check
hoses

for
cracks
or
softness
.
Check
clamps
for
looseness
.
Check

the
coolant
leve¡
and
check
for
evidence
of
coolantleaks
from

the
engine
.

Check
that
the
radiator
fins
are
not
blocked
with
dirt
or
de-

bris
.
Clean
the
radiator
using
low-pressure
water
or
com-

pressed
air
.
Blow
outward,
fromthe
engine
side
out
.

Inspect
the
coolant
pump
by
first
removing
the
drive
belt

from
the
pump
.
Firmly
grasp
opposite
sídes
of
the
pulley
and

check
for
play
in
all
directions
.
Spin
the
pulley
and
check
that

the
shaft
runs
smoothly
.

NOTE-

The
coolant
provides
lubrication
for
the
pump
shaft,
soan
occasional
drop
of
coolant
leaking
from
the
pump
is
acceptable
.
If
coolant
drips
steadily
from
the
vent
hole,
the
pump
should
be
replaced
.

The
cooling
system
becomes
pressurized
at
normal
operat-

ing
temperature,
which
raises
the
boiling
point
of
the
coolant
.

Leaks
may
prevent
the
system
from
becoming
pressurized,

allowing
the
coolant
to
boil
at
a
lower
temperature
.
If
visual
ev-

idence
is
inconclusive,
a
cooling
system
pressure
test
can

help
to
pinpointhard-to-find
leaks
.

If
the
cooling
system
is
full
of
coolant
and
holds
pressure,

the
next
most
probable
cause
of
overheating
are
:

"
Faulty
radiator
fan

"
Loose
or
worn
drive
belt

"
Failed
thermostat
or
coolant
pump

"
Clogged/plugged
radiator
or
coolant
passages
.

NOTE
-

"
Some
early
style
coolant
pumps
were
fitted
wíth
fi-
berlplastic
type
impellers
.
Over
time,
this
impeller
can
wear
away
and
result
in
overheating
.
The
plastic
im-
peller
can
also
slip
or
free-wheel
on
the
pump
shaft
.
If
the
engine
overheats
and
no
other
faults
canbe
found,
theold
style
impeller
may
be
the
cause
of
the
problem
.

"
Only
pumps
with
the
updated
metal
impeller
should
be
used
for
replacement
.

Fig
.
3
.



Clutch
master
cylinder
mounting
bolts
.

Clutch
slave
cylinder,
replacing

0012589

Tightening
Torques

"
Clutch
master
cylinder
to
bulkhead
..
22
Nm
(17
ft-Ib)
"
Fluid
line
to
master
cylinder

orslave
cylinder
.................
16
Nm
(12
ft-1b)

The
clutch
slave
cylinder
is
mounted
on
the
left
side
of
the

transmission
.



CLUTCH
MECHANICAL

1
.
Remove
brake
fluid
reservoir
cap
.
Using
a
clean
sy-

ringe,
remove
brake
fluid
from
reservoir
.

2
.
Disconnect
fluid
hose
from
slave
cylinder
.
Place
a
pan

under
hose
to
catch
any
excess
fluid
.

3
.
Unbolt
slave
cylinder
from
transmission
.
See
Fig
.
4
.

4
.
Installation
is
reverse
of
removal,
noting
the
following
:

"
Check
for
wear
on
pushrod
.
Any
other
wear
except
on

tipis
caused
by
misalignment
of
clutch
components
.

"
Lightly
coat
pushrod
tip
with
molybdenum
disulfide

grease
(Molykote
0
Longterm
2
or
equivalent)
.

"
During
installation
be
sure
pushrod
tip
engages
recess

in
clutch
release
lever
.

"
Fill
fluid
reservoir
with
clean
fluid
.

"
Bleed
clutch
hydraulics
as
described
earlier
.

CLUTCH
210-
3

Fig
.
4
.



Clutch
slave
cylinder
mounting
bolts
(arrows)
.

Tablea
.
ClutchDisc
Diameter

Model



Diameter

3181/is/iC



215
mm
(8
.46
in)

325i/is/iC



228
mm
(8
.98
in)
323is/iC

328i/is/iC



240
mm
(9
.45
in)
M3

0012715

Tightening
Torques

"
Clutch
slave
cylinder

to
transmission
.
.
................
22
Nm
(17
ft
lb)
"
Fluid
line
to
slave
cylinder
......
.17
Nm
(10-12
ft
lb)

The
transmission
must
be
removed
from
the
engine
to
ac-

cess
the
clutch
mechanical
components
.
It
is
recommended

that
the
clutch
disc,
pressure
plate
and
release
bearing
be
re-

placed
duringa
clutch
overhaul
.
Be
sure
to
check
the
bottom

of
the
bellhousing
for
oil
.
If
engine
oil
is
found,
check
for
a

faulty
rear
crankshaft
oil
seal
.

CLUTCH
MECHANICAL

240-
6



AUTOMATIC
TRANSMISSION

14
.
Remove
transmission
by
pulling
back
and
down
.
Lower

jack
to
allow
transmission
to
clear
vehicle
.



Tightening
Torques

"
ATF
drain
plug
to
ATF
sump

CA
UTION-



MS
270R/A4S
310R
....
..
....
.
..
25
Nm
(18
ft-Ib)

Do
not
allow
the
torque
converter
to
fati
off
the



ASS
310Z(M10
plug)
..
..
..
.
.
..
.
..
16
Nm
(12
ft-Ib)

transmission
inputshaft
.



"
ATF
fill
plug
to
ATF
sump

MS
270R/A4S
310R
..
..
....
..
..
.
33
Nm
(24
ft-Ib)

15
.
Installation
is
reverse
of
removal,
noting
the
following
:



MS
310Z(M30
plug)
......
.
.
..
.
.
100
Nm
(74
ft-Ib)

"Blowoutofcoolerlineswithlow-pressurecompressed



"
ATF
cooler
lines
(A4S
270R/A4S
310R)

air
and
flush
coolerwith
clean
ATF
twice
before
reat-



Coupling
nuts
............
.
.
..
..
.
20
Nm
(15
ft-Ib)

taching
lines
to
transmission
.



Hollow
bolts
.........
.
.....
..
..
.
37
Nm
(28
ft-Ib)

"
Reinforcing
cross
brace

CAUTION-



to
chassis
(M10)
.............
.
..
.
42
Nm
(31
ft-Ib)

"
Wear
safety
glasses
when
working
with
com-



"
Torque
converter

pressedair
.



to
driveplate
(M10)
.........
..
.
..
45
Nm
(33
ft-Ib)

"
Transmissionsupport
crossmember
to
chassis

"
Do
not
reuse
ATF
after
flushing
.



M8
......................
22-24
Nm
(16-17
ft-1b)

M10
................
.
....
..
.
..
42
Nm
(31
ft-Ib)

"
Install
new
sealing
washers
on
hollow
bolts
.



"
Transmissíon
to
engine
(Torx-head
with
washer)

"
Insta¡¡
new
O-rings
on
transmission
cooler
lines,
where



M8
......................
..
.
..
21
Nm
(15
ft-Ib)

applicable
.



M10
.....................
..
..
.
42
Nm
(31
ft-Ib)

"
Inspect
driveplate
for
cracks
or
elongatedholes
.
Re-



M12
................
.
....
..
.
..
72
Nm
(53ft-Ib)

place
if
necessary
.

"
Check
to
be
sure
torque
converter
is
seated
correctly

in
transmission
during
final
installation
.

"
When
mounting
transmission
to
engine,
the
three

mounting
tabs
on
torque
converter
must
be
aligned

with
indentations
on
driveplate
.
Use
an
alignment

dowel
to
line
up
bolt
holes,
if
necessary
.
"
Fill
transmission
with
clean
ATF
until
oil
leve¡
is
even
with
fill
hole
.
Then
check
fluid
leve¡
as
described
ear-
lier
.

"
Adjust
gearshift
mechanism
.
See
250
Gearshift
link-

age
.

NOTE-

Torx-head
mounting
bolts
shouldalwaysbe
used
with
washers
to
prevent
difficult
removal
.

TRANSMISSION
REMOVAL
AND
INSTALLATION

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

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

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

340-2
BRAKES

When
troubleshooting,
keep
in
mind
that
tire
inflation,
wear

and
temperature
can
affect
braking
and
suspension
.
See310

Front
Suspension
for
more
information
on
front
suspension

parts
inspection
.

Table
a
lists
symptoms
of
brake
problems,
their
probable

causes,
and
suggested
corrective
actions
.

Table
a
.
Brake
System
Troubleshooting

Symptom



1



Probable
cause



1



Repairs

Brake
squeal



a
.
Incorrectly
installed
brake
pads
or



a
.
Check
component
installation
.
parking
brake
shoes
b
.
Brakepad
carriers
dirty
or
corroded



b
.
Remove
brake
pads
and
clean
calipers
.
c
.
Brake
pad
anti-rattle
springs
faulty
or



c
.
Install/replace
anti-rattle
springs
.
missing
d
.
Brakepads
heat-glazed
or
oil-soaked



d
.
Replace
brake
pads
.
Clean
rotors
.
Replace
leaking
calipers
as
required
.
e
.
Wheel
bearings
worn
(noise
most



e
.
Replace
worn
bearings
.
See310
Front
Suspension
pronounced
when
turning)



or
330
Rear
Suspension
.

Pedal
goes
to
f
loor
when
braking



a
.
Brake
fluid
leve¡
low
due
to
system



a
.
Check
fluidlevel
and
inspect
hydraulic
system
for
leaks



signs
of
leakage
.
Fill
and
bleed
system
.
b
.
Master
cylinder
faulty



I
b
.
Replacemaster
cylinder
.

Low
pedal
after
system
bleeding



1
a
.
Master
cylinder
faulty



1
a
.
Replace
master
cylinder
.

Pedal
spongy
or
brakes
work
only



a
.
Air
in
brake
fluid



a
.
Bleedsystem
.
when
pedal
is
pumped



b
.
Master
cylinder
faulty
(interna¡
return



b
.
Replacemaster
cylinder
.
spring
weak)
c
.
Leaking
line
or
hose
unions



c
.
Repair
or
replace
lines
and
hoses
.
Bleed
system
.

Excessive
braking
effort



a
.
Brake
pads
wet



a
.
Use
light
pedal
pressure
to
dry
pads
while
driving
.
b
.
Brake
pads
heat-glazed
oroil-soaked



b
.
Replace
brake
pads
.
Clean
rotors
.
Replace
leaking
calipers
.
c
.
Vacuum
booster
or
vacuum
hose
con-



c
.
Inspect
vacuum
lines
.
Test
vacuum
booster
and
re
nections
to
booster
faulty



place
as
required
.
Test
vacuum
non-return
valve
for
one-way
air
flow
.

Brakes
pulsate,
chatter
or
grab



a
.
Warped
brake
rotors



a
.
Resurface
or
replace
rotors
.
b
.
Brake
padsworn



b
.
Replace
brake
pads
.
c
.
Brake
pads
heat-glazed
or
oil-soaked



c
.
Replace
brake
pads
.
Clean
rotors
.
Replace
leaking
calipers
.

Uneven
braking,
car
pulís
to
one



a
.
Incorrect
tire
pressures
or
worn
tires



a
.
Inspect
tire
condition
.
Check
and
correct
tire
pres-
side,
rear
brakes
lock



sures
.
b
.
Brake
pads
on
one
side
of
car
heat-



b
.
Replace
brake
pads
.
Clean
rotors
.
Replace
leaking
glazed
or
oil-soaked



calipers
.
c
.
Caliper
or
brake
pads
binding



c
.
Clean
and
recondition
brakes
.
d
.
Worn
suspension
components



d
.
Inspect
for
worn
or
damaged
suspension
compo-
nents
.
See
310
Front
Suspension
or
330
Rear
Sus-
pension
.

Brakes
drag,
bind
or
overheat



a
.
Brake
caliper
or
brake
pads
binding



a
.
Clean
or
replace
caliper
.(
b
.
Master
cylinder
faulty



b
.
Replacemaster
cylinder
.

WARNING
-

On
cars
with
All
Season
Traction
(AST),
special
BMW
service
equipment
is
required
to
properly
bleed
the
ABS/AST
system
.
For
safety
reasons,
the
brake
system
on
carswith
ABS/AST
must
not
be
bled
using
the
procedures
described
inthis
repair
group
.

BLEEDING
BRAKES

Brake
bleeding
is
usually
done
for
one
of
two
reasons
:
Ei-
ther
to
replace
oíd
brake
fluid
as
part
of
routine
maintenance
or
to
expel
trapped
air
in
the
system
that
resulted
from
open-
ingthe
brake
hydraulic
system
during
repairs
.

BLEEDING
BRAKES

Alwaysuse
new
brake
fluid
from
an
unopened
container
.It

is
important
to
bleed
the
entire
system
when
any
part
of
the

hydraulic
system
has
been
opened
.
On
cars
not
equipped
with
traction
control
(AST),
brake
system
bleeding
should
be

done
with
a
pressure
bleeder
.
On
cars
with
AST,
brake
bleed-

ing
should
be
done
by
an
authorized
BMW
dealer
.

WARNING
-

On
cars
with
All
Season
Traction
(AST),
special
BMW
service
equipment
is
requíred
to
properly
bleed
the
ABS/AST
system
.
For
safetyreasons,
the
brake
system
on
carswith
ABS/AST
must
not
be
bled
using
the
procedures
described
inthís
repair
group
.