1998 BMW M3 rear brake hose

113
Cylinder
Head
Removal
and
Installation

GENERAL
.
...............
.
.
.
.
.
.......
113-1



CYLINDER
HEAD,
6-CYLINDER
.
.
.
.
.
.
.
113-10

Cylinder
head,
removing
(6-cylinder
engine)
..
113-10
CYLINDER
HEAD,
4-CYLINDER
..
.
...
.
.
113-1



Cylinder
head,
installing
(6-cylinder
engine)
...
113-15
Cylinder
head,
removing
(4-cylinder
engine)
...
113-1



E
Cylinder
head,
installing
(4-cylinder
engine)
...
113-6

GENERAL



CYLINDER
HEAD,
4-CYLINDER

The
information
given
inthis
repair
group
assumes
that
the

engine
is
installed
in
the
engine
bay
.
For
cylinder
head,
cam-



Cylinder
head,
removing

shaft,
and
valvetrain
disassembly
and
reconditioning
informa-



(4-cylinder
engine)
tion,
see116
Cylinder
Head
and
Valvetrain
.

For
ease
of
use
this
removal
procedure
is
broken
into
sub-
In
the
procedures
given
below,
engines
are
referred
to
by



sections,
as
follows
:
engine
code
.
If
necessary,
see100
Engine-General
for
en-

gine
code
and
application
information
.

NOTE-

If
a
head
gasket
problem
is
suspected,
acompression
test
will
usually
detectthe
fault
.
See
100
Engine-Gen-
eral
for
compression
testing
information
.

Special
BMW
service
tools
are
required
to
properly
remove
and
install
the
cylinder
head
on
both
the
4-cylinder
and
6-cyl-

inder
engines
.
The
special
tools
are
used
to
time
the
val-

vetrain
to
the
crankshaft
and
to
remove
the
Torx
(El
2)
head

bolts
.
Read
the
procedure
through
before
beginning
thejob
.

Cover
al¡
painted
surfaces
before
beginning
the
removal

procedure
.
As
an
aid
to
installation,
label
all
components,

wires,
and
hoses
before
removing
them
.
Do
not
reuse
gas-

kets,
O-rings
or
seals
during
reassembly
.

WARNING
-

Due
to
risk
of
personal
injury,
be
sure
the
engine
is
cold
before
beginning
the
removalprocedure
.

CYLINDER
HEAD
REMOVAL
AND
INSTALLATION



113-1

General
Coolingsystem,
draining
Cylinder
head
cover,
removing

Intake
manifold,
removing

Timing
chains,
uncoupling

Cylinder
head
assembly,
removing

WARNING
-

Allow
engine
to
cool
before
beginning
this
proce-
dure
.

General

1
.
Disconnect
negative
(-)
cable
from
battery
.

CAUTION
-

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

"
Disconnecting
the
battery
may
erase
fault
codees)

stored
in
control
module
memory
.
Check
for
fault

codes
using
special
BMW
diagnostic
equipment
.

NOTE-

The
battery
is
mounted
in
the
luggage
compartment
behind
the
right
side
trim
panel
.

2
.
Working
underneath
vehicle,
remove
front
exhaust
pipe

from
exhaust
manifold
.
See
Fig
.
1
.

3
.
Disconnect
vacuum
hose
fitting
from
brake
booster
on

rear
bulkhead
.
Plug
opening
in
booster
and
hose
end
.

CYLINDER
HEAD,
4-CYLINDER

119-2



LUBRICATION
SYSTEM

NOTE-
Component
Location



If
the
light
does
not
go
out,
thewiring
to
theswitch
is"
Oil
pressure
switch



most
likely
grounded
somewhere
between
the
switch

all
engines
.......
...
.
..
......
ora
oil
filter
housing



terminal
and
the
warning
light
.
Sea
Electrical
Wiring

Diagrams
atrearof
manual
for
electrical
schematics
.

CAUTION-

Some
oil
may
drain
out
as
the
oil
pressure
switch
is
removed
.
Use
a
rag
to
soak
up
any
spills
.

2
.
Install
pressure
gauge
in
place
of
switch
.

3
.
With
gauge
instalied,
start
engine
and
allow
to
reach

operating
temperature
.
Check
oil
pressureboth
cold

and
hot
.

NOTE-

For
the
most
accurate
test
results,
the
engine
oil
(and
filter)
shouldbe
newand
of
the
correct
grade
.

Oil
Pressure

"
¡dle
(mínimum)
..
.
.
..............
.
.
0
.5
bar
(7psi)

"
Regulated
pressure
(elevated
engine
speed)

4-cylinder
engines
..
......
4
.3
±
0
.2
bar
(63
t3
psi)

6-cylinder
engines
.
.
.............
.
4
.0
bar
(59
psi)

4
.
Remove
pressure
gauge
and
reinstall
pressure
switch
.

If
testing
shows
low
oil
pressure,
one
or
more
of
the
follow-

ing
conditions
may
be
indicated
:
OIL
PAN

"
Worn
or
faulty
oii
pump
.

"
Worn
or
faulty
engine
bearings



The
oil
pancan
be
removed
with
the
engine
instalied,
al-

Severe
engine
wear
.



though
specíal
enginesupport
equipment
will
be
needed
.

Al¡
of
these
conditionsindicate
the
need
for
major
repairs
.

Oil
pressure
warning
system,
testing

When
the
ignition
is
tumed
ora,
the
oil
pressure
warning
light

comes
ora
.
When
the
engine
ís
started
and
the
oil
pressure
ris-

es
slightly,
the
oil
pressure
switch
opens
and
thewarning
light

goes
out
.
Make
sure
the
oil
leve¡
is
correct
before
making

tests
.

1
.
Turra
ignition
switch
ora
.

"
Warning
light
ora
instrument
panel
must
light
up
.

2
.
Remove
connector
from
oil
pressure
switch
.

"
Warning
light
ora
instrument
panel
must
go
out
.

OIL
PAN

3
.
If
warning
light
does
not
light
when
ignition
is
ora,
re-

move
connector
from
oil
pressure
switch
anduse
a

jumper
wire
to
ground
connector
terminal
to
a
clean

metal
surface
.

NOTE
-

If
the
warning
light
comes
ora,
check
the
switch
as
de-
scríbed
in
the
nextstep
.
If
the
warning
light
does
not
come
ora,
thewiring
to
the
instrument
cluster
or
to
the

light
itself
isfaulty
.

4
.
To
test
switch,
connect
ara
ohmmeter
between
terminal

in
switch
body
and
ground
.
With
engine
off,
these

should
be
continuity
.
With
engine
running,
oil
pressure

should
opera
switch
and
there
should
beno
continuity

Replace
a
faulty
switch
.

WARNING
-

Keep
in
mind
that
low
oil
pressure
may
be
prevent-

ing
the
switch
from
tuming
the
light
out
.
If
the
light

remains
ora
while
the
engine
is
running,
check
the

oil
pressure
asdescribed
earlier
.
Do
not
drive
the
car
until
the
problem
is
corrected
.
Theengine
may
be
severely
damaged
.

Oil
pan,
removing
and
installing

(4-cylinder
engines)

1
.
Raise
car
arad
place
securely
ora
jackstands
.

2
.
Remove
splash
shíeld(s)
from
under
engine,
where
ap-

plicable
.

3
.
Drain
engine
oil
as
described
in
020
Maintenance
Pro-
gram
.

4
.
Disconnect
vacuum
hose
adapter
from
vacuum
brake

booster
at
rear
of
engine
compartment
.

5
.
Remove
oil
dipstick
guide
tube
mounting
nut
and
pull
guide
tube
from
oil
pan
.
See
Fig
.
2
.

2
.
Remove
fuel
tank
filler
cap
.

3
.
Remove
rearseat
cushion
and
pull
back
insulation
mats
to
expose
fuel
tank
access
covers
.
See
Fig
.
2
.

uui3140

Fig
.
2
.



Right
side
fuel
tank
access
cover
under
rear
seat
cushion
.

4
.
Remove
right
and
left
access
covers
to
expose
fuel
hoses
and
electrical
connections
at
tank
.

5
.
Label
fuel
hoses
.
Then
disconnect
hoses
and
harness
connectors
from
fuel
sending
units
and
fuel
pump
.
See
Fig
.
3
.

FUELTANK
AND
FUEL
PUMP



160-
3

NOTE-

"
If
necessary,
push
fuel
level
sender
arm
toward
fuel
pump
assembly
to
facilitate
removal
.

"
BMW
special
tool
no
.
16
1
020
should
beused
tore-
move
and
install
the
threaded
collar
.
Damage
to
thecollar
may
result
if
the
special
tool
is
not
used
.

"
Pump
out
contents
of
each
tanklobe
using
approved
pumpinglextraction
equipment
and
flexible
fuel-grade
hose
.

WARNING
-

Fuel
may
be
spilled
.
Do
not
smoke
or
work
near
heaters
or
other
fire
hazards
.

7
.
Installation
of
sending
units
is
reverse
of
removal,
not-
ing
the
following
:

"
Use
new
sealing
rings
when
installing
pump/sending
unit
assemblies
.
"
Be
sure
that
fuel
line
connections
point
in
same
direc-tion
as
they
carne
out
.
"
Fill
tank
and
check
for
leaks
by
running
engine
.

CA
UTION-

Before
starting
the
engine,
fill
the
fuel
tank
with
at
least
1.5
gallons
(5liters)
of
fuel
.
The
pump
will
be
damaged
if
you
run
it
without
fuel
.

Fuel
tank,
removing
and
installing

1.
Disconnect
negative
(-)cablefrom
battery
:

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
viii
.

2
.
Remove
fuel
tank
filler
capand
drain
tank
as
described
earlier
.

3
.
Working
in
left
access
tank
access
hole
(under
rear

seat
cushion),
remove
vent
pipe
fromtank
.

4
.
Working
inside
car,
disconnectparking
brake
cable
ends
from
parking
brake
lever
.
See
340
Brakes
.

5
.
Working
underneath
car,
gently
pry
fuel
lines
away
from
retaining
bracket
in
front
of
tank
.
Remove
clamps
and
disconnect
fuel
hoses
as
shown
in
Fig
.
4
.

6
.
Remove
exhaust
system
and
heat
shield
as
described

ooisiai



in
180
Exhaust
System
.
See
Fig
.
5
.

Fig
.
3
.



Fuel
pump/fuel
level
sender
assembly
in
top
offuel
tank
(right
side
shown)
.
Disconnect
supply
hose
(A),
return
hose
(B)
and



7
.
Remove
driveshaft
.
See
260
Driveshaft
.
harness
connector
(C)
.

8
.
Pull
parking
brake
cables
backward
away
from
bottom
of

6
.
Unscrew
threaded
collars
from
fuel
tank
.
Slowly
with-



fuel
tank,
disengaging
them
from
brackets
as
needed
.

draw
fuel
sender
assemblies
from
tank,allowing
fuel
to
drain
off
.

FUEL
TANKAND
LINES

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

Wheel
bearing

Fig
.
7
.



Rear
wheel
bearing
assembly
.

Circlip



Drive
flange



Collar
nut

0012152

Rear
wheel
bearing,
replacing

1
.
Raise
car
and
support
safely
.
Remove
rear
wheel
.

2
.
Remove
drive
axle
as
described
later
.



6
.
Remove
bearíng
retainer
circlip
from
trailing
arm
.

3
.
Remove
brake
caliper
assembly
and
rotor
as
described



7
.
Using
appropriate
press
tools,
pull
bearing
assembly

in
340
Brakes
.
Leave
brake
hose
connected
to
caliper
.



out
of
trailing
arm
bearing
housing
.

Suspend
caliper
assembly
from
chassís
using
stiff
wire
.

8
.
Inspect
bearing
housing
for
any
damage
or
contamina

4
.
Remove
ABS
pulse
sensor
.
See
Fig
.
8
.



tion
.
Clean
housing
bore
thoroughly
before
installing

new
bearing
.
Make
sure
al¡
thread
bores,
bolts,
nuts

and
mating
surfaces
are
clean

Fig
.
8
.



ABS
pulse
sensor
being
removed
.

5
.
Remove
drive
flange
from
bearing
assembly
.
See
Fig
.

9
.

NOTE-

If
the
inner
bearing
race
remains
attached
to
the
drive

flange,
use
BMW
special
tool
nos
.
007
500
and
33
1

312
or
equivalents
to
separate
inner
race
from
flange
.

REAR
SUSPENSION



330-
5

0013125

Fig
.
9
.



Drive
flange
being
removed
from
bearing
assembly
using
im-
pact
style
puller
.

9
.
Install
new
bearing
assembly
using
press
tools
.
Apply

force
only
to
outer
race
when
installing
bearing
.

WARNING
-

M3
installation
:
redsealing
ríng
on
rear
wheel
bear-

ing
must
face
outward
.
Otherwíse
ABS
will
not
func-
tion
.

10
.
Insta¡¡
new
circlip
.
The
old
circlip
should
never
be
re-

used
.

CAUTION-

Make
sure
that
the
bearing
is
pressed
in
far
enough
to
contact
the
shoulder
at
the
back
sideof
the
housing
and
that
the
circlip
is
fully
seated
in
its
groove
.

11
.
Draw
drive
flange
into
bearing
using
appropriate
press

tools
.
Support
bearing
inner
race
when
pressing
in

0013223



drive
flange
.

NOTE-

BMW
specifies
special
tools
to
pull
the
drive
fiange
through
the
wheel
bearing
into
position
.
If
using
alter-
native
tools,
be
sure
to
support
the
bearing
inner
race
when
pressing
orpulling
the
drive
flange
finto
place
.

REARWHEEL
BEARINGS

330-
6



REAR
SUSPENSION

12
.
Install
brake
caliper
assembly
and
rotor
as
described
in

340Brakes
.

13
.
Install
drive
axie
as
described
below
.

Tightening
Torques

"
Brake
rotor
to
drive
flange
.........



16
Nm
(12
ft-ib)

"
Brake
caliper
to
trailing
arm
........
67
Nm
(50
ft-Ib)

"
Drive
axie
collar
nut
to
drive
flange
..
.
..
..............
250
Nm
(184
ft-Ib)
M3
.....
...
..
.
.............
.
300
Nm
(221
ft-Ib)

"
Road
wheel
to
hub
.........
100±10
Nm
(74±7
ft-Ib)

DRIVE
AXLES

The
drive
axles
use
constant-velocity
(CV)
joints
on
both
ends
.
To
replace
a
CV
joint
or
dust
boot,
the
drive
axie
must
be
removed
fromthe
car
.
The
components
of
the
drive
axie
are
illustrated
in
Fig
.
10
.

Drive
axie,
removing
and
installing

1
.
Raise
rear
of
car
.
Remove
rear
wheel
.

Dust
cover

Fig
.
10
.
Driveaxie
assembly
.

DRIVE
AXLES

Inner
CV
boot
kit

-Reinforcement

WARNING
-

Make
sure
that
the
car
is
firmly
supportedon
jack
stands
designed
for
the
purpose
.
Place
the
jack
stands
beneatha
structural
chassis
point
.
Do
not
place
jack
stands
undersuspension
parts
.

2
.
Pry
off
dust
cap
from
center
of
wheel
hub
.

3
.
Remount
wheel
and
lug
boits
.

4
.
Lower
car
to
ground
.
With
an
assistant
applying
brakes,

loosen
collar
nut
.
Do
not
remove
completely
.
See
Fig
.

11
.

The
drive
flange
collar
nut
is
tightened
to
a
torque
of
250
Nm
(184
ft-Ib)
.
Make
sure
the
car
is
firmly
on
the
ground
.

5
.
Raisecar
andremove
wheel
.

6
.
Remove
brake
caliper
assembly
and
rotor
as
described
in
340
Brakes
.
Leave
brake
hose
connected
to
caliper
.
Suspend
caliper
assembly
from
chassis
using
stiff
wire
.

7
.
Remove
drive
axie
from
drive
flange
.
See
Fig
.
12
.
Sus-

pend
drive
axie
from
chassis
using
stiff
wire
.

Outer
CV
boot
kit

Drive
axle

Outer
CV
joint

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
.