air bleeding BMW M3 1993 E36 Workshop Manual

170
Radiator
and
Cooling
System

GENERAL
.
.
.....
.
...
.
.
.
.
.
....
.
.
.
.
.
.
.
.170-1

Coolant
Pump
and
Thermostat
........
.
.
.
.
170-1

Radiator
and
Expansion
Tank
.........
.
...
170-1

Cooling
Fans
.
....
.
.
.
.
.
.
.
.
.
.....
.
......
170-2

Warnings
and
Cautions
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
170-2

TROUBLESHOOTING
...
.
.
.
...
.
.
.
.
.
.
.
.
.170-2

Cooling
System
Pressure
Test
...
.
.
.
.
.
.
.
.
.
170-3

Thermostat
Quick
Check
.
.
.
.
...
.
.
.
.
.
.
.
.
.
170-3

Temperature
Gauge
Quick
Check
.
.
.
.
.
.
.
.
.
170-3

Cooling
fan,
testing
.
.
.
.
........
.
.
.
.
.
.
.
.
.
170-4

COOLING
SYSTEM
SERVICE
.
.
.
.
.
.
.
.
.
.
170-5

Coolant,draining
and
filling
.
.
......
.
.
.
.
.
..
170-5

Cooling
system,
bleeding

(radiator
with
integral
expansion
tank)
.....
170-6

GENERAL

This
section
covers
repair
and
troubleshooting
information
for
the
engine
cooling
system
.
For
heater
core
and
related
heating
and
air
conditioning
components,
see640
Heating
and
Air
Conditioning
.

Coolant
Pump
and
Thermostat

A
centrifuga¡-type
coolant
pump
is
mounted
to
the
front
of

the
engíne
.
The
belt-driven
pump
circulates
coolant
through

the
system
whenever
the
engíne
is
running
.
A
thermostat
con-

trols
the
flow
of
coolant
into
the
radiator
.

When
the
engíne
is
cold
the
thermostat
is
closed
so
coolant

bypasses
the
radiator,
recirculating
from
the
engíne
directly

back
to
the
pump
.
When
the
engíne
reaches
operating
tem-

perature,
the
thermostat
opens
and
coolant
circulates
through

the
whole
system
including
the
radiator
.

Radiator
and
Expansion
Tank

The
radiator
is
a
crossflow
design
.
A
translucent
expansion

tank
provides
for
coolant
expansion
at
higher
temperatures
and

easy
monitoringof
the
coolant
leve¡
.

On
4-cylinder
modeis,
the
radiator
expansion
tank
is
integral

with
the
radiator
.
See
Fig
.
1
.

RADIATOR
AND
COOLING
SYSTEM



170-1

Belt-driven
cooling
fan,
replacing
.
.......
.
.
.
170-7

Electric
cooling
fan,
replacing
.
.
.
.....
.
.
.
.
.
170-8

Auxiliary
cooling
fan,
replacing
.
.
.....
.
.
.
.
.
170-8

Thermostat,
replacing
.
.
.
.
.
.
.
.
.
.....
.
.
.
.
.
170-9
Coolant
pump,
replacing
..........
.
.
.
.
.
.
170-10

RADIATOR
SERVICE
.....
.
......
.
.
.
.
.
.
170-11

Radiator,
removing
and
installing
....
.
.
.
.
.
.
170-11

TABLES

a
.
Coolant
Temperature
Sensor
Wire
Colors
...
.
..
.
.
170-3b
.
Auxiliary
Cooling
Fan
Switching
Temperatures
.:.
.170-4
c
.
Auxiliary
Cooling
Fan
Temperature
Switch
Tests
..
..
.
...
...
.
.............
.
..
.
.
170-5d
.
Cooling
System
Capacities
..............
..
.
.
.
170-6

A
.
Expansion
tank



C
.
Dualtemperature
fan
switch
B
.
Radiator
drain
screw

Fig
.
1
.
Radiator
assembly
with
integral
expansion
tank
(4-cylinder
engine)
.

On
6-cylinder
models,
a
standalone
expansion
tank
is
used
.

On
cars
with
automatic
transmission,
ATF
is
circulated
through
an
additional
heat
exchanger
(ATF
cooler)
.

GENERAL

170-6



RADIATOR
AND
COOLING
SYSTEM

Fig
.
6
.



Radiator
drain
plug
(arrow)
.

WARNING
-

Coolant
is
poisonous
.
Itis
especially
lethal
to
pets
.

Cleanup
spills
immediately
and
rinse
the
area
with

water
.

NOTE
-

The
block
drain
plug
is
located
on
the
exhaust
side
of
the
engine,
near
the
reas
of
the
engine
.

4
.
Reinstall
radiator
and
engine
block
drain
plugsusing

new
sealing
washers
.
Leave
heater
controis
on
full

warm
.

5
.
Using
a
coolantmixture
of
50%
antifreeze
and
50%
dis-

tilled
water,
fill
system
slowly
On
radiator
with
integral

expansion
tank,
bleed
cooling
system
as
described
be-

low
.

NOTE-

"
Tap
water
may
cause
corrosion
of
radiator,
engine
and
coolant
hoses
.

"
Coolant
can
often
be
reused
provided
itis
clean
and
less
than
twoyears
old
.
Do
not
reuse
coolant
when
re-
placing
damaged
engine
parts
.
Contaminated
coolant
may
damage
the
engine
or
cooling
system
.

Tabled
.
Cooling
System
Capacities

Engine



j
Capacity

4-cylinder



1
6
.5
liters
(6.9
qt)

6-cylinder
M50/M52



10
liters
(10
.6
qt)
S50US/S52US



10
.5
liters
(11
.1
qt)

COOLING
SYSTEM
SERVICE

Tightehing
Torques

"
Radiator
drain
plug
to
radiator
...
2-3
Nm
(18-27
in-lb)

"
Engine
block
drain
plug
to
block



.
.
..
25
Nm
(18
ft-Ib)

Cooling
system,
bleeding

(radiator
with
integral
expansion
tank)

NOTE
-

On
radiators
with
a
separate
expansion
tank,
ableed

screw
is
not
provided
.
The
cooling
system
with
sepa-

rate
expansion
tank
is
self
bleeding
via
the
vent
hose

on
the
expansion
tank
.

Air
maybecome
trapped
in
the
system
during
filling
.

Trapped
air
can
prevent
proper
coolant
circulation
.
Whenever

the
coolant
is
drained
and
filled,
the
system
should
be
bled
of

trapped
air
.

1
.
With
engine
cold,
add
coolant
to
expansion
tank
until

level
reaches
COLD
(KALT)
mark
on
tank
.

2
.
Loosen
bleed
screw
on
radiator
expansion
tank
.
See

Fig
.
7
.

0011976

Fig
.
7
.



Cooling
system
bleed
screwon
radiator
(arrow)
.
Note
cold
level
mark
on
expansion
tank
.

3
.
M3
models
:
Loosen
bleed
screw
on
thermostathous-

ing
.

4
.
Set
temperature
controls
in
passenger
compartment
to

fui¡
warm
and
turn
ignition
on
position
(do
not
start
en-

gine)
.

GENERAL
..
.
.
.
.
.
.
.
.
.
.
.
.
.
......
.
......
210-1



CLUTCH
MECHANICAL
.
.
.
.
.
...
.
.....
.
.
210-3

CLUTCH
HYDRAULICS
.
.
.
.............
210-1



Clutch,
removing
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
210-4

Clutch,inspecting
and
installing
.
.
.
.
.
.
.
.
.
.
.
.210-5Clutch
hydraulic
system,



Transmission
pilot
bearing,replacing
.
.
.
.
...
210-6
bleeding
and
flushing
.
.
.
.
.
.......
.
.....
210-2

Clutch
master
cylinder,
replacing
..
.
.
.
.
.
...
210-2



Table

Clutch
slave
cylinder,
replacing
...
.
.
.
.
.
.
.
.
210-3



a
.
Clutch
Disc
Diameter
.............
..
..
.
......
210-3

GENERAL



CLUTCH
HYDRAULICS

This
repair
group
covers
replacement
of
the
clutch
mechan-



The
Clutch
is
hydraulically
actuated
by
the
master
and
slave
¡cal
and
hydraulic
components
.
Special
tools
may
be
required



cylinders
.
Clutch
disc
wear
is
automatically
taken
upby
the
for
some
of
the
procedures
.
Read
the
procedure
through
be-



pushrod
travelof
the
slave
cylinder,
making
periodic
adjust-fore
beginning
a
job
.



ments
unnecessary
.

NOTE-

See200
Transmission-General
for
transmission
applicatíon
information
.

The
major
components
of
the
clutch
system
are
shown
in

Fig
.
1
.

Engine



Pressure
plate

flywheel,,
assembly

Clutch

Flywheel
bolt

Pressure
plate
release
lever



Release
lever

Fig
.
1
.



Clutch
assembly
and
hydraufcs
.

210
Clutch

Release
bearing

Pushrod

A
soft
or
spongy
feel
to
the
clutchpedal,
long
pedal
free-
play,
or
grinding
noises
from
thegears
while
shifting
can
all
in-
dicate
problems
with
the
Clutch
hydraulics
.
In
these
circum-
stances
it
is
best
to
start
with
a
clutch
fluid
flush,
followed,
if

necessary,
byreplacement
of
the
hydraulic
parts
.

From
brake
fluid
reservoir

CLUTCH
210-1

0

0

Transmission
inputshaft

Clutch
master
cylinder

Bulkhead

Slave
cylinder
6535

CLUTCH
HYDRAULICS

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
.

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

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
.

When
bleeding
the
brakes,
startat
the
wheel
farthest
from



4
.
Close
bleeder
screw
and
release
brake
pedal
.
Refill
the
master
cylinder
and
progress
in
the
following
order
:



brake
fluid
reservoir
and
proceed
to
rear
left
wheel
.

"
right
rear
brake



5
.
Proceed
with
the
remaining
wheels
using
the
order
list-

"
left
rear
brake



ed
earlier
.

"
rightfront
brake

"
left
front
brake

Pressure
bleeding
brakes

(except
carswith
AST)

1
.
Top
off
brake
fluid
in
reservoir
and
connect
pressure

bleeder
to
reservoir
.
Connect
bleeder
hose
and
bottle
to
right
rearcaliper
bleeder
screw
.
Pressurize
system

to
approximately
1
bar
(14
.5
psi)
.

BRAKES
340-
3

Tightening
Torques

"
Bleeder
screws
:

7
mm
screw
..........
..
.
.
.
.
......
5
Nm
(4
ft-Ib)

9
mm
screw
..........
..
.
..
.......
6
Nm
(5
ft-Ib)

BRAKE
PADS,
CALIPERS,
AND
ROTORS

CAUTION-



TheE36
front
brake
caliper
is
shown
in
Fig
.
2
.
The
rear

Do
not
exceed
a
pressure
of
2
bar
(29
psi)
when



brake
caliper
is
shown
in
Fig
.
7
.

pressure
bleeding
the
brake
system
.
Excessive
pressure
will
damage
the
brake
fluid
reservoir
.



Brake
pads
canbe
replaced
without
disconnecting
the
brake
fluid
hose
from
the
caliper
or
having
to
bleed
the
brakes
.

2
.
Have
a
helperhold
brake
pedal
down
.



The
rotors
can
be
replaced
without
disassembling
the
wheel
huband
bearing
.
Always
machine
or
replace
rotors
in
parts
.

3
.
Open
bleeder
screw
.
See
Fig
1
.
Have
helper
slowly
,



Replace
pads
in
sets
.

pump
brakes
about10
times
with
bleeder
screw
open,

holding
pedal
down
on
the
last
pump
.
When
escaping



WARNING-

fluid
is
free
of
air
bubbles,
close
bleeder
screw
.



"
Althoughsemi-metallicandmetallicbrake
friction
materials
in
brake
pads
or
shoes
no
longer
con

CAUTION-



tain
asbestos,
they
produce
dangerous
dust
.

Bleeder
hose
must
alwaysremain
submersed
in



"
Treat
all
brake
dust
asa
hazardous
material
.
the
clean
brake
fluid
whenever
the
bleeder
valve
is
open
.



"
Do
not
create
dust
by
grinding,
sanding,
orclean-
ing
brake
friction
surfaces
with
compressed
air
.

"
Breathing
any
brake
dust
can
cause
serious
dis-
eases
such
as
cancer,
and
may
result
in
death
.

Brake
pads,
replacing

This
procedure
is
applicable
lo
both
front
and
rear
brakes
.

Front
and
rear
brake
assemblies
are
basically
the
same,
ex-

cept
that
the
rear
brake
rotors
house
the
parking
brake
mech-

anism

1
.
Raise
car
andremove
wheels
.

WARNING
-

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

2
.
Remove
plastic
caps
from
guide
bolts
and
then
remove

guide
bolts
.
See
Fig
.
3
.

0012113



3
.
If
applicable,
disconnect
brake
pad
wear
sensor
con-
Fig
.
1
.



Brake
caliper
bleeder
screw
(arrow)
.



nector
and
remove
wiring
from
its
holder
.

4
.
Remove
anti-rattle
clip
from
caliper
.
See
Fig
.
4
.

BRAKE
PADS,
CALIPERS,
AND
ROTORS

Brake
rotor,
removing
and
installing

Brake
rotors
shouldalways
be
replaced
in
pairs
.

Fig
.
9
.



Brake
rotor
mounting
screw
(arrow)
.

3
.
Inspect
rotor
for
excessive
grooving,
cracks,
and
warp-

ing
.
Check
rotor
thickness
.
See
Table
b
.

4
.
Installation
is
reverse
of
removal
.

"
Clean
rotor
with
brakecleaner
before
installing
.

"
If
brake
fluid
hose
veas
removed
or
loosened,
brake

systemmustbe
bled
as
described
aboveunder

Bleeding
Brakes
.

BRAKES
340-
7

5
.
Once
brake
assembly
is
instalind,
depress
brakepedal

several
times
to
adjust
caliper
and
pads
.

"
Pedal
should
feel
firm
and
be
at
proper
height
.

"
Check
fluid
leve¡
.
Top
up
if
necessary
.

NOTE-

M3
models
use
directional
brake
rotors
and
mustbe
in-



NOTE-

stalled
on
the
proper
side
.
Part
numbes
are
cast
finto



When
installing
new
rear
brake
rotors,
the
parking

therotors
.
A
part
that
ends
in
an
odd
number
is
a
left



brakeshouldbe
adjusted
.
See
Parking
Brake
.

rotor
.
One
that
ends
in
an
even
number
is
a
right
rotor
.

1.
Remove
caliper
as
described-above
and
hang
from



Tightening
Torques
chassis
using
stiff
wire
.



"
Brake
rotor
to
wheel
hub
..........
16
Nm
(12
ft-Ib)

"
Front
brake
caliper
to
steering
arm
...
110
Nm
(81
ft-Ib)

NOTE-



"
Rear
brake
caliper
to
traíling
arm
....
67
Nm
(50
ft-Ib)

Do
notloosen
caliper
brake
hose
.



"
Road
wheel
to
hub



...
..
.
100
±
10
Nm
(74
t
7
ft-Ib)

2
.
Remove
mountingscrew
holding
rotor
to
wheel
hub
.



,

See
Fig
.
9
.



Table
b
.
Brake
Rotor
Reconditioning
Specificati*M`

Front
Rear

Vented
rotor
wear
limit
(min
.
thickness)



20
.4
mm
(0
.803
in.)

Solid
rotor
wear
limit
(min
.
thickness)



8
.4
mm
(0.331
in
.)

M3
models
wear
limit
(min
.
thickness)



26
.4mm
(0
.977
in
.)



18
.4
mm
(0
.723
in
.)

Axial
runout
(max
.)
rotor
removed



0
.05
mm
(0
.002
in
.)



0
.05
mm
(0
.002
in
.)
rotor
installed



0
.20
mm
(0
.008
in
.)



0
.20
mm
(0
.008
in
.)

CAUTION-

M3
brake
rotors
must
not
be
machined
.

MASTER
CYLINDER

The
brake
master
cylinder
is
mounted
to
the
front
of
the
vac-

uum
booster
on
the
driver
side
bulkhead
.

Master
cylinder,
removing
and
installing

1
.
Using
a
clean
syringe,
empty
brake
fluid
reservoir
.

WARNING
-

Brake
fluid
is
highly
corrosive
and
dangerous
to
the

environment
.
Dispose
of
it
properly
.

NOTE-

On
original
equipment
rotors,
the
mínimum
allowable



2
.
Disconnect
brake
fluid
leve¡
sender
connector
from
fluid

thickness
is
stamped
on
the
rotor
hub
.
Measure
the
rotor



reservoi
r
cap
.

brakingsurface
with
a
micrometer
at
eight
to
ten
different

points
and
use
the
smallest
measurement
recorded
.



3
.
Disconnect
brake
fluid
lines
frommaster
cylinder
.
See

Fig
.
10
.
Disconnect
hydraulic
clutch
system
supply
line
.

4
.
Unscrew
mounting
nuts
and
remove
master
cylinder

from
brake
booster
.

5
.
Make
sure
all
nuts,
fluid
couplings,
thread
bores,
and

mating
surfaces
are
clean
.

MASTER
CYLINDER