1998 BMW M3 check engine

240-
6



AUTOMATIC
TRANSMISSION

14
.
Remove
transmission
by
pulling
back
and
down
.
Lower

jack
to
allow
transmission
to
clear
vehicle
.



Tightening
Torques

"
ATF
drain
plug
to
ATF
sump

CA
UTION-



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

Do
not
allow
the
torque
converter
to
fati
off
the



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

transmission
inputshaft
.



"
ATF
fill
plug
to
ATF
sump

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

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



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

"Blowoutofcoolerlineswithlow-pressurecompressed



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

air
and
flush
coolerwith
clean
ATF
twice
before
reat-



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

taching
lines
to
transmission
.



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

"
Reinforcing
cross
brace

CAUTION-



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

"
Wear
safety
glasses
when
working
with
com-



"
Torque
converter

pressedair
.



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

"
Transmissionsupport
crossmember
to
chassis

"
Do
not
reuse
ATF
after
flushing
.



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

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

"
Install
new
sealing
washers
on
hollow
bolts
.



"
Transmissíon
to
engine
(Torx-head
with
washer)

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



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

applicable
.



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

"
Inspect
driveplate
for
cracks
or
elongatedholes
.
Re-



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

place
if
necessary
.

"
Check
to
be
sure
torque
converter
is
seated
correctly

in
transmission
during
final
installation
.

"
When
mounting
transmission
to
engine,
the
three

mounting
tabs
on
torque
converter
must
be
aligned

with
indentations
on
driveplate
.
Use
an
alignment

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

"
Adjust
gearshift
mechanism
.
See
250
Gearshift
link-

age
.

NOTE-

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

TRANSMISSION
REMOVAL
AND
INSTALLATION

Fig
.
10
.
Align
contact
slide
(1)
with
slot
in
switch
housing
(2)
before
in-
stalling
gear
position/neutral
safety
switch
.

Fig
.
11
.
Engage
release
button
pin
to
hole
in
pull
rod
before
installing

The
automatic
shiftlock
uses
an
electríc
solenoid
to
lock
the
selector
lever
in
P
or
N
.
Depressing
the
foot
brake
withthe
ig-
nition
on
energizes
the
solenoid,
allowingthe
lever
to
be
moved
into
a
drive
gear
.
The
solenoid
is
energized
only
when

the
engine
speed
is
below
2,500
rpmand
thevehicle
speed
is

below
3
mph
.
The
solenoid
ís
mounted
in
the
right-hand
side

of
theselector
lever
housing
.
See
Fig
.
12
.

1
.
With
engine
running
and
car
stopped,
place
selector
le-
ver
in
P
or
N
.

2
.
Without
depressing
brake
pedal,
check
that
selector
le-

ver
is
locked
in
position
P
or
N
.

3
.
Depress
brakepedal
firmly
.
Solenoid
should
be
heard

to
energize
.

GEARSHIFT
LINKAGE



250-
5

Fig
.
12
.
Automatic
shiftlock
prevents
drive
gear
selection
until
the
brakepedal
is
depressed
.

4
.
Check
thatselector
lever
can
now
be
moved
out
of
P
or
N
.

NOTE
-

The
next
test
should
be
performed
in
anopen
area
with
the
parking
brake
on
and
with
extreme
caution
.

5
.
With
selector
lever
in
P
or
N
and
brake
pedal
de-

pressed,
raise
engine
above
2,500
rpm
.
Check
that
se-

lector
lever
cannotbe
moved
outof
P
or
N
.

shift
lever
handle
.



If
any
faults
are
found
check
the
electrical
operation
of
the
shiftlock
solenoid
and
check
for
wiring
faultsto
or
from
the
Automatic
shiftiock,
checking
function



transmission
control
module(TCM)
.
See610
Electrical

(automatic
transmission)



Component
Locations
and
Electrical
Wiring
Diagrams
.

NOTE
-

The
solenoid
is
controlled
viathe
TCM,
using
brakepedal
position,
engine
speed,
and
road
speed
as
con-
trolling
inputs
.

AUTOMATIC
TRANSMISSION
GEARSHIFT

DRIVESHAFT
SERVICE
.
...
.
.
.
...
.
..
.
.
.260-3

Driveshaft,
aligning
...............
.
...
.
.
260-3

Driveshaft,
removing
..............
.
.
.
.
.
.
260-4

260
Driveshaft

DRIVESHAFT
260-1

GENERAL
.
.
.
.
.
.
.
.....
.
.
.
........
.
...
.
260-1



Driveshaft,
installing
.
....
.
..
.
............
260-4

Flex-disc,
replacing
.....
.
.
.
.............
260-5
TROUBLESHOOTING
..
.
.
.
...
.
.........
260-1



Center
bearing
assembly,
replacing
.
......
.260-6
Frontcentering
guide,
replacing
..
.
.......
.
260-7

TABLE

a
.
Driveshaft
Troubleshooting
.
.
...
......
.
....
..
.
.
260-2

GENERAL



NOTE-

For
rear
drive
axlerepair
information,
see330
Rear
The
two-piece
driveshaft
is
joined
in
thecenter
by
a
sliding



Suspension
.
splined
coupling
.
This
coupling
compensates
for
fore
and
aft
movement
of
the
drive
line
.
The
driveshaft
ís
connected
to
the



Driveshaft
noise
or
vibration
may
be
caused
by
worn
or
transmission
bya
rubber
flex-disc
and
to
the
final
drive
by
a



damaged
components
.
Check
the
universal
joints
for
play
.
universal
joint
.
It
is
supported
in
the
micidle
by
a
center
support



With
the
driveshaft
installed,
pull
and
twist
the
driveshaft
while
bearing
.
The
bearing
is
mounted
in
rubber
to
isolate
vibration
.



watching
the
joint
.
The
BMW
specificationfor
play
is
very
See
Fig
.
1
.



small,
so
almost
any
noticeableplay
could
indicate
a
problem
.

TROU
BLESHOOTING



Check
thetorque
of
thefasteners
at
the
flange
connections
.
Check
therubber
of
the
flex-disc
and
center
bearing
for
dete

The
source
of
driveline
vibrations
and
noise
can
be
difficult



rioration
or
tearíng
and
check
for
preload
at
the
center
bearing

to
pinpoint
.
Engine,
transmission,
rear
axle,
or
wheel
vibra-



with
a
visual
inspection
.
Check
the
driveshaft
for
broken
or

tions
can
be
transmitted
through
the
driveshaft
to
the
car



missing
balance
weights
.
The
weights
are
welded
tabs
on
the

body
.
Noises
from
the
rear
of
thecar
may
be
caused
by
final



driveshaft
tubes
.
In
addition
to
inspecting
for
faulty
driveshaft

drive
problems,
orby
faulty
wheel
bearings,
drive
axies,
or



parts,
the
installed
angles
of
the
driveshaft
should
also
be

evenworn
or
improperly
inflatedtires
.



considered
.

Flex-disc

Center
universal
joint

Fig
.1
.



Driveshaft
and
final
drive
assembly
.

Rear
section
Splined
shaft



of
driveshaft
Center
support



`



Clamping
sleeve
bearíng
assembly

Differential
inputflange

0013110

TROUBLESHOOTING

260-2
DRIVESHAFT

Further
inspection
requires
removal
of
the
driveshaft
.

Check
the
front
centering
guide
on
the
transmission
output
flange
for
damage
or
misalignment
.
Also
check
runoutatthe

transmission
outputflange
and
output
shaft,
and
at
the
final

drive
input
flange
.
Check
the
bolt
hole
bores
in
theflange
for

wear
and
elongation
.

Driveshaftflange
runout
(max
.
allowable)

"
Transmission
outputflange

axial
play
...
.
..
...
..
.
.......
0
.10
mm
(0
.004
in
.)

radial
play
.......
...
.
.
.......
0
.07
mm
(0
.003
in
.)

"
Final
driveinput
flange
radial
play
(measured
at

driveshaft
centering
lip)
..
......
0
.07
mm
(0
.003
in
.)

Spinthe
center
bearing
and
check
for
the
smooth
operation

without
play
.
Check
that
thesplines
of
the
sliding
coupling

move
freely
.
Clean
and
lubricate
the
splines
with
molybdenum

disulfide
grease
(Molykote
®
Longterm
2
or
equivalent)
.

Check
the
universal
joints
for
wear
or
binding
.
If
any
joint
isdif-

ficult
to
move
or
binds,
the
driveshaft
section
should
be
replaced
.

Table
a
.
Driveshaft
Troubleshooting

NOTE-

With
the
driveshaft
installed,
theactual
amount
that
the
universal
joints
pivot
is
limited
.
For
the
most
accurate

test,
check
universal
joints
in
their
normal
range
of

movement
.

If
inspection
revealsnothing
wrong
with
the
driveshaft,
it

may
need
to
be
rebalanced
.
This
can
be
done
by
a
speciality

driveshaft
repair
shop
.
Also,
check
the
alignment
ofthe
drive-

shaft
as
described
below
.

NOTE-

Minor
driveshaftvibrations
can
often
be
correctedsim-

ply
by
disconnecting
the
driveshaftat
the
finaldrive,

and
repositíoning
the
driveshaft
90°,
180°
or270°
inre-
lationto
the
final
drive
input
flange
.

Table
a
lists
symptoms
of
driveshaft
problems
and
their

probable
causes
.
Most
of
the
repair
information
is
contained

within
this
repair
group
.

Symptom



Probable
cause



Corrective
action

1
.
Vibration
when



a
.
Incorrect
preload
of
center
bearing
.



a
.
Check
preload
of
center
bearing
.
Readjust
preload
.
See
Fig
.
6
.

starting
off
(forward



b
.
Center
bearing
rubber
deteriorated
.



b
.
Inspect
center
bearing
and
rubber
.
Replace
if
necessary
.
orreverse)
.



c
.



Flex-disc
damaged
or
worn
.



c
.



Inspect
flex-disc
.
Replace
if
necessary
.

TROUBLESHOOTING

d
.
Engine
or
transmission
mounts
faulty
.
I
d
.
Inspect
engine
and
transmission
mounts
.
Align
or
replace,
if
nec-

essary
.

e
.
Front
centering
guide
worn,
or



e
.
Check
front
centering
guide
and
replace
if
necessary
.
Check

driveshaft
mounting
flanges
out
of



runout
of
driveshaft
flanges
.

round
.

f
.



Universal
joints
worn
or
seized
.



f
.



Check
universal
joint
play
and
movement
.
Replace
driveshaft
if

necessary
.

g
.
Sliding
coupling
seized
.



g
.
Remove
driveshaft
and
check
movement
of
sliding
coupling
.

Clean
coupling
splines
and
replace
parts
asnecessary
.

h
.
Driveshaft
misaligned
.



h
.
Check
driveshaft
alignment
.

2
.
Noise
during
on/off



a
.
Finaldrive
components
worn
or



a
.
Remove
final
drive
and
repair
.

throttle
or
when



damaged
(excessive
pinion-to-ring-

engagíng
clutch
.



gear
clearance)
.

b
.



Drive
axleor
CV
joint
faulty
.



b
.



Inspect
drive
axles
and
CV
joints
.
Repair
or
replace
as
neces-
sary
.

c
.
Sliding
coupling
seized
.



c
.
Remove
driveshaft
and
check
movement
of
sliding
coupling
.

Clean
coupling
splines
and
replace
parts
as
necessary
.

3
.
Vibration
at
25
to
30



a
.
Front
centering
guideworn,
or



a
.
Check
front
centering
guide
and
replace
if
necessary
.
Check
mph
(40
to
50



driveshaft
mounting
flanges
out
of



runout
of
driveshaft
mounting
flanges
.
km/h
).



round
or
damaged
.

b
.
Universal
joints
worn
or
seized
.



b
.
Check
universal
joint
play
and
movement
.
Replace
driveshaft
if
necessary
.

c
.



Flex-disc
damaged
or
worn
.



c
.



Inspect
flex-disc
.
Replace
if
necessary
.

d
.
Center
bearing
rubber
deteriorated
.



d
.
Inspect
center
bearing
.
Replace
if
necessary
.

e
.
Sliding
coupling
seized
.



e
.
Remove
driveshaft
and
check
movement
of
sliding
coupling
.
Clean
coupling
splines
and
replace
parts
asnecessary
.

f
.



Misaligned
installed
position
.



f
.



Check
driveshaft
alignment
.

Symptom



1



Probable
cause

4
.
Vibration,
audible



a
.
Front
centering
guide
worn,
or



a
.
Check
front
centering
guide
and
replace
if
necessary
.
Check
rumble
over35
mph



driveshaft
mounting
flanges
out
of



runout
of
driveshaft
mounting
flanges
.
(60
km/h)
.



round
or
damaged
.

b
.
Mounting
flange
bolts
loose
or
holes



b
.
Remove
driveshaft
and
check
transmissionoutput
flange
and
worn
.



final
drive
input
flange
.
Replace
if
necessary
.
c
.
Driveshaft
unbalanced
.



c
.
Check
driveshaft
for
loose
or
missing
balance
weights
.
Have
driveshaft
rebalanced
or
replace
if
necessary
.

DRIVESHAFT
SERVICE

Driveshaft,
aligning

d
.
Universal
joints
worn
or
seized
.



d
.
Check
universal
joint
play
and
movement
.
Replace
driveshaft
if
necessary
.

e
.
Sliding
coupling
seized
.



e
.
Remove
driveshaft
and
check
movement
of
sliding
coupling
.
1



Clean
coupling
splines
or
replace
parts
asnecessary
.

f
.



Incorrect
preload
of
center
bearing
.



f
.



Check
preload
of
center
bearing
.
Readjust
if
necessary
.
g
.
Center
bearing
faulty
.



g
.



Replace
center
bearing
.

h
.
Final
drive
rubber
mount
faulty



h
.
Inspect
final
drive
rubber
mount
and
replace
if
necessary
.i.



Driveshaft
misaligned
.



i.



Check
driveshaft
alignment
.

Repair
kits
for
the
universal
joints
are
not
available,
and
it
is
not
common
practice
to
repair
the
universal
joints
on
BMW
driveshafts
.
Worn
or
damaged
universal
joints
usually
require
replacement
of
that
section
of
the
driveshaft
.

The
driveshaft
is
balanced
to
cose
tolerances
.
Whenever
it
is
to
be
removed
or
disassembied,
the
mounting
flanges
and
driveshaft
sections
should
bemarked
with
paint
or
a
punch

before
proceeding
with
work
.
This
will
ensure
that
the
drive-
shaft
can
be
reassembled
or
installed
in
exactlythe
same
ori-
entation
.

Universal
joint
play

"
Maximum
allowable
...........
0.15
mm
(0.006
in
.)

The
alignment
of
the
driveshaft
does
not
normally
need
to
be
checked
unless
the
engine/transmission
orthe
final
drive
havebeen
removed
and
installed
.
If,
however,
all
other
parts
of
the
driveshaft
havebeen
inspected
and
found
to
be
okay,
butthere
is
still
noise
or
vibration,
driveshaft
alignment
should

be
checked
.

There
aretwo
important
driveshaft
alignment
checks
.
The
first
is
to
make
sure
that
the
driveshaft
runs
straight
from
the
transmission
to
the
final
drive
;
without
any
variation
from
side-

to-side
caused
by
misalignment
ofthe
engine/transmission
in
its
mounts
.
Make
a
basic
check
by
sighting
along
the
drive-

shaft
from
back
lo
front
.
Any
misalignmentshould
be
apparent
from
the
center
bearingforward
.
To
adjustthe
side-to-side
alignment,
loosen
the
transmission
or
engine
mounts
to
repo-

sition
them,
then
retighten
the
mounts
:
The
driveshaft
should

be
exactly
centered
in
the
driveshaft
tunnel
.
See
Fig
.
2
.

Table
a
.
Driveshaft
Troubleshooting
(continued)

DRIVESHAFT
260-3

Corrective
action

b
:izó
Fig
.
2
.



Driveshaft
side-to-side
alignment
.
Driveshaft
should
be
cen-
tered
in
driveshaft
tunnel
.

The
second
important
driveshaft
alignment
check
is
more
complicated
.
It
checks
the
amount
the
driveshaft
is
angled
vertically
at
the
joints
.
This
angle
is
known
as
driveshaft
de-
flection
.

In
general,
there
should
be
little
deflection
in
the
driveshaft
between
the
engine,
thecenter
bearing,
and
the
final
drive
.
Precise
checks
require
theuse
of
a
large
protractor
or
some
other
means
of
measuring
the
angle
of
the
engine
and
the
fi-

nal
drive
and
comparing
these
angles
to
the
angle
of
the
drive-

shaft
sections
.

To
change
the
deflection
angle,
shims
can
be
placed
between
the
center
bearing
and
the
body
or
between
the
transmission

and
íts
rear
support
.
When
using
shims
to
change
a
deflection

angle,
keep
in
mind
that
the
angle
of
adjacent
joints
will
also
change
.
Deflection
anglesshould
beas
small
as
possible
.

DRIVESHAFTSERVICE

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

6
.
Disconnect
ABS
electrical
connectors
.
Label
and
then

disconnect
brake
lines
from
hydraulic
brake
unit
.
Plug

openíngs
.
See
Fig
.
12
.

~
~
A
1/
B
'1v
C
~
F

lu
11
-ri
J
.

0013244
A
.
Right
front



F



Front
from
master
cylinder
B
.
Leftfront



R
.
Rear
from
master
cylinder
C
.
Rear

Fig
.
12
.
Brake
fluid
linesat
ABS
hydraulic
unit
.

WARNING
-

"
On
cars
with
All
Season
Traction
(AST),
special
BMW
service
equipment
is
required
to
properly
bleed
the
Antilock
Brake
System
(ABS)
.
Removal
of
the
ABS
hydraulic
unit
is
not
recommended
un-
less
this
equipment
is
available
.
For
safetyrea-
sons,
the
brake
system
on
cars
with
ABS
must

not
be
bled
using
the
procedures
described
inthis
repair
group
.

"
Do
not
mix
up
the
fluid
fines
at
the
ABS
hydraulic
unit
Label
all
connections
before
disconnecting
.

7
.
Remove
ABS
hydraulic
unit
from
engine
compartment
.

8
.
Working
inside
car,
remove
panel(s)
frombeneath

steering
column
to
access
pedal
assembly
.
See513
In-

terior
Trim
.

12
.
Make
sure
al¡
nuts,
fluid
couplings,
thread
bores
and

mating
surfaces
are
clean
.

BRAKES
340-
9

0011261

Fig
.
13
.
Brake
pedal
clevispin
and
retaining
clip
(A)
.
Brake
booster
mounting
nuts
shown
at
arrows
.

13
.
If
necessary,
mount
master
cylinder
to
vacuum
booster

using
a
new
O-ríng
and
newself-locking
nuts
.

CAUTION-

Do
not
over-torque
the
master
cylinder
mounting
bolts
.
This
could
damage
the
brake
booster
and
prevent
proper
vacuum
build-up
.

14
.
Installation
is
reverse
of
Rmoval
.

"
Bleed
brakes
as
described
earlier
.

"
Check
and,
if
necessary,
adjust
brake
light
switch

above
brake
pedal
.

Tightening
Torques

"
Brakemaster
cylinder
to

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

"
Brake
booster
to
bulkhead
.
.
..
..
...
22
Nm
(16
ft-Ib)

"
Brake
fluidline
to
master
cylinder
or

ABS
hydraulic
unit
.......
.
..
17-19
Nm
(13-14
ft-lb)
9
.
Remove
clip
and
clevis
pin
from
brake
booster
pushrod

and
disconnect
it
from
brakepedal
.
Remove
brake

booster
mounting
nuts
.
See
Fig
.
13
.
NOTE-

10
.
Working
in
engine
compartment,
remove
brake
booster



When
replacing
the
brake
booster
one-way
valve
or
together
with
master
cylinder
.



vacuum
hose,
install
the
valve
so
that
the
molded
arrow

is
pointing
toward
the
intake
manifold
.
Use
new
hose

11
.
If
booster
or
master
cylinder
O-ring
is
being
replaced,



clamps
.

disconnect
master
cylinder
from
brake
booster
.

BRAKE
BOOSTER