Master cylinder BMW 328i 1997 E36 Workshop Manual

GENERAL
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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
.

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

300-2



SUSPENSION,
STEERING
AND
BRAKES-GENERAL

Steering

INTEGRATED
SYSTEMS

The
steering
linkage
connects
the
rack-and-pinion
unit
through
tie
rodsto
the
steering
arms
.
The
tie
rod
ends
allow
the
wheels
to
pivot
and
react
to
suspension
travel
.

Rear
Suspension

The
rear
axle
carrier
is
the
main
mounting
point
for
the
final

drive
housing
and
the
rear
suspension
components
.

Trailing
arms
locatethe
rear
wheels
and
anchorthe
springs,

shocks
and
stabilizer
bar
.
Driveaxies
with
constant-velocity

(CV)
joints
at
both
ends
transfer
power
from
the
differential
to

the
road
wheels
.
The
differential
is
mounted
to
the
rearaxle

carrier
through
rubber
mountsand
bushings
to
hele
isolate

drivetrain
noise
and
vibration
.

Brakes

E36
cars
areequipped
with
power
disc
brakes
with
an
inte-
gral
antilock
brakes
(ABS)
.
The
parking
brake
is
a
dual-drum

system
integrated
with
the
rear
brake
rotors
.
See
Fig
.
3
.

Power
assist
is
provided
by
a
vacuum
booster
when
the
en-

gine
is
running
.
The
brakepedal
pushrod
is
connected
directly

to
the
master
cylinder,
so
failure
of
the
vacuum
booster
does

not
normally
result
in
total
brake
failure
.

0012124



Each
disc
brakeuses
a
caliper
with
a
single
hydraulic
cylin-
Fig
.
2
.



Front
suspension
control
arm
(arrow)
.



der
.
Brake
pads
in
the
left
front
and
right
rear
contain
wear

sensors
.
When
the
padsneed
replacement,the
sensors
illu-
The
front
suspension
is
designed
with
minimum
positive



minate
a
light
on
the
dashboard
.
steering
offset
.
This
geometry
contributes
to
stability
when

traction
is
unequalfrom
side
to
side
.
Suspension
travel
is
lim-



Tires
and
Wheels
ited
by
rubber
bump
stops
.

The
three
point
mounting
of
each
L-shaped
control
arm
ere-



Tiresize
is
critica¡
to
the
proper
operatíon
of
the
E36
ABS
or

cisely
controls
the
front-to-rear
and
side-to-side
position
of
the



ABS/AST
system
.
Severa¡
different
styles
of
wheels,
in
15,16

strut,
while
the
flexibility
of
the
joints
and
mounts
alsoallows



and
17
inch
diameters,
are
available
from
an
authorized
BMW

the
movement
necessary
for
suspension
travel
.
The
control



dealer
.

arm
mounting
points
are
designed
with
anti-dive
geometry
.

The
suspension
reduces
the
normaltendency
for
the
front
of



NOTE-
the
vehicle
to
dive
under
hard
braking
.



Aftermarket
wheelsshould
be
selected
wlth
care
.
Im-
properly
fitted
wheels
can
contact
anddamage
sus

Control
arm
position
is
fixed,
with
no
adjustment
provisions



pension,
brakeorbodycomponentsandmayadversely

on
the
control
arms
for
alter¡ng
front
wheel
al
ignment
.
A
stabi-



affect
vehicle
stability
.

lizer
bar
mounted
to
both
control
arms
heles
to
reduce
body
rol¡
whencomering
.



INTEGRATED
SYSTEMS

Antilock
Brake
System
(ABS)
is
standard
on
all
E36
cars
.

The
variable-assist
power
steering
system
consists
of
an



Standard
on
some
models
and
installed
as
optional
equipment
on

engine-driven
hydraulic
pump,
a
rack-and-pinion
type
steer-



others,
is
All
Season
Traction
(AST)
.

ing
gear,
and
connecting
linkage
to
the
road
wheels
.
TheE36
utilizes
an
engine-speed
dependent
variable
effort
steering



Antilock
Brake
System
(ABS)

system
.
At
low
speeds,
maximum
power
assist
is
provided
to
ease
parking
and
city
driving
.
Athigh
speeds,
assist
is
re-



The
electronically-controlled
ABS
maintains
vehícle
stabili
duced
to
ensure
stability
.



ty
and
control
during
emergency
braking
by
preventing
wheel
lock-up
.
ABS
provides
optimum
deceleration
and
stability
dur-

Wheel
brake
caliper

Electronic
control
module
Fig
.
4
.



Schematic
representation
of
ABS
.

SUSPENSION,
STEERING
ANDBRAKES-GENERAL



300-3

Fig
.
3
.



Schematic
view
ofdual
circuit
brakes
with
4-channel
ABS
.

ing
adverse
conditions
.
It
automatically
adjusts
brake
system
hydraulic
pressure
at
each
wheel
to
prevent
wheel
lock-up
.

The
system's
main
components
arethe
wheel
speed
(pulse)
sensors,
the
ABS
control
module,
and
the
hydraulic

control
unit
.
See
Fig
.
4
.

Warning
lamp

u
Master

Whee

_

l
speed



I-lydraulic



cylinder

sensor



control
unit



0012135

UNI

The
wheel
speed
sensors
continuously
send
wheel
speed
signals
to
the
control
module
.
See
Fig
.
5
.
The
control
module
compares
these
signals
to
determine,
in
fractions
of
a
second,
whether
any
of
the
wheels
areabout
to
lock
.
If
any
wheel
is
nearing
a
lock-up
condition,
the
module
signals
the
hydraulic
unit
to
maintain
or
reduce
pressure
at
the
appropriatewheel(s)
.
Pressure
is
modulated
by
electrically-operated
sole-

noid
valves
in
the
hydraulic
unit
.

Fig
.
5
.



ABS
wheelspeed
sensor
.

0006563

INTEGRATED
SYSTEMS

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

340-
8
BRAKES

Fig
.
10
.
Brake
fluid
linesat
master
cylinder
(arrows)
.

6
.
If
fluid
reservoir
was
removed,
install
it
carefully
using
new
sealing
grommets
.

7
.
Mount
master
cylinder
to
brake
booster
using
a
new
0-
ring
and
new
self-locking
nuts
.

CAUTION-

Use
cave
not
to
over-torque
the
master
cylinder
mounting
nuts
.
This
could
damage
the
brake
booster
and
prevent
proper
vacuum
build-up
.

0012164

8
.
Connect
all
brake
fluid
lines
.
Connect
hydraulic
clutch
hose
to
brake
fluid
reservoir
.

9
.
Reconnect
fluid
leve¡
sender,
and
bleed
entire
brake
systemas
described
earlier
.

BRAKE
BOOSTER

BRAKE
BOOSTER

The
brake
booster
is
mounted
to
the
bulkhead
on
the
driver
sideofthe
engine
compartment,
directly
behind
the
brake
master
cylinder
.
See
Fig
.
11
.

0015225
Fig
.
11
.
Brake
booster
(arrow)
.
A
is
vacuum
hose
from
intake
mani-
fold
.
B
is
one-way
valve
.
Intake
manifold
vacuum
acts
ona
large
diaphragm
in
the
brake
booster
to
reducebrake
pedal
effort
.

Brake
booster,
removing
and
installing

1
.
Disconnect
negative
(-)
cable
from
battery
.

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
vi¡¡
.

Tightening
Torque

"
Brake
master
cylinder
to



2
.
Using
a
clean
syringe,
empty
brake
(luid
reservoir
.

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



WARNING-
"
Brake
fluid
hose
to
caliper
....
17-19
Nm
(13-14
ft-Ib)



Brake
fluid
is
highly
corroslve
and
dangerous
to
the
environment
.
Dispose
of
it
properly
.

3
.
Remove
brake
fluid
level
sender
connector
from
reser-
voir
cap
.

4
.
Disconnectbrake
fluid
lines
from
master
cylinder
.
Plug
openings
.

5
.
Disconnect
engine
vacuum
hose
from
brake
booster
.