1998 BMW M3 rear brake line

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

230-
4



MANUAL
TRANSMISSION

Output
shaft
sea¡,
replacing

(transmission
installed)

1
.
Raise
and
safely
support
vehicle
.
Support
transmission

with
transmission
jack
.

WARNING
-

"
When
raising
thecar
using
a
floor
jack
or
a
hy-
draulic
lift,
carefully
position
the
jack
pad
to
pre-vent
damaging
the
car
body
.
A
suitable
liner
(wood,
rubber,
etc
.)
should
be
placed
between
the
jack
and
the
car
to
prevent
body
damage
.

"
Watch
the
jack
closely
.
Make
sure
it
stays
stable
and
does
not
shift
or
tilt
.
As
the
car
is
raised,
the
car
may
roll
slightly
and
the
jack
may
shift
.

2
.
Remove
driveshaft
.
See
260
Driveshaft
.

3
.
Remove
transmission
crossmember
and
lower
trans-

mission
at
rear
.

CAUTION-

Tilting
the
engine
to
lower
thetransmissíon
can
lead
to
damage
to
various
componente
due
to
lackof
clearance
.
-On
cars
with
AST
(traction
control)
remove
throt-
tle
body
before
tilting
engine
.
-Remove
brake
fluid
reservoir
if
necessary
.

4
.
Bend
back
and
remove
collar
nut
lockplate
.

5
.
Hold
flange
steady
andremove
collar
lock
nut
(use

30mm
thin-walled
deep
socket
.)
See
Fig
.
5
.

Fig
.
5
.



Use
holding
tool
when
loosening
output
shaft
collar
nut
.

6
.
Remove
flange
.
If
necessary,
use
a
puller
.

7
.
Use
a
sea¡
puller
to
remove
seal
from
transmission
housing
.
See
Fig
.
6
.

8
.
Coat
new
sea¡
wíth
transmission
fluid
and
drive
into
po-
sition
until
it
is
flush
with
housing
.
See
Fig
.
7
.

TRANSMISSIONSERVICE

Fig
.
6
.



Puller
used
to
remove
transmission
seal
.

Fig
.
7
.



Output
shaftseal
being
installed
using
seal
driver
(BMW
spe-
cial
tool
no
.
232
300)
.

9
.
Reinstall
output
flange
(and
shims,
if
applicable)
to
out-

put
shaft
.

NOTE-

On
Getrag
S5D200G
and
S5D
250G
transmissions
BMW
recommends
heating
theoutputflange
to
about
176°F
(80°C)
to
aid
in
installation
.
This
canbe
done
by
placing
the
flange
in
hot
water
.

10
.
Coat
bearingsurface
ofcollar
nut
withsealer
and
install
nut
.
Tighten
collar
nut
in
two
stages
.
Insta¡¡
new
lock-
plate
.
Bend
tabs
into
flange
grooves
.

NOTE-

BMW
recommends
the
use
of
a
sealer
such
as
Loctite
®
242
when
installing
the
flange
collar
nut
to
prevent
oil
from
leaking
past
the
threads
.

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
.

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

330-
1
0



REAR
SUSPENSION

Trailing
arm,
removing
and
installing

1
.
Raise
rear
end
of
car
and
remove
wheel
.

WARNING
-

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

2
.
Remove
drive
axle
as
described
earlier
.

3
.
Remove
brake
rotor
and
caliper
as
described
in
340

Brakes
.
Do
not
remove
brake
line
from
caliper
.
Hang

caliper
from
body
with
wire
.

4
.
Remove
parking
brakecable
frombrake
shoe
expand-

er
.
See
340
Brakes
.

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

Fig
.
17
.

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

WARNING
-

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

REAR
SUSPENSION
ARMS

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

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

0013220

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

row)
.

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

as
described
later
.

9
.
Remove
ABS
wheel
speed
sensor
from
rear
wheel

bearing
housing
.
Unclip
sensor
wiríng
from
trailing
arm
.

If
removing
right
trailing
arm,
separate
brake
pad
wear

sensor
connector
.
See
Fig
.
19
.

0012104

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

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

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

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

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

GENERAL



TROUBLESHOOTING

WARNING
-

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

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

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

BMW
E36
models
areequipped
with
vacuum
power-assist-

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

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

axle
indicates
when
brake
padsneed
replacement
.
The
dual

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

NOTE-

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

340
Brakes

BRAKES
340-1

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



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

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



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

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



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



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



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

BRAKE
PADS,
CALIPERS,



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



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

TABLES

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

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

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

during
braking
or
will
increase
the
Brake
pedalforce
required

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

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

Visually
check
the
hydraulic
system
startingat
the
master

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

brake
pedal
down
hard
with
the
engine
running
.
The
pedal

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

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

and
couplings
for
leaks,
kinks,
chafing
and
corrosion
.

Check
the
Brake
booster
by
pumping
the
Brake
pedal
ap-

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

for
any
visiblefaults
before
suspecting
a
faulty
brake
booster
.

Check
for
strong
vacuum
at
the
vacuum
hose
fitting
at
the

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

Worn
or
contaminated
brake
pads
will
cause
poor
braking

performance
.
Oil-contaminated
or
glazed
pads
will
cause

stopping
distances
to
increase
.
Inspect
the
rotors
for
glazing,

discoloration
and
scoring
.
Steering
wheel
vibration
while

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

TROUBLESHOOTING

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
.

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