Ac system BMW 540i 1998 E39 Workshop Manual

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31 0-2
I Front Suspension
This repair group covers the repair and replacement of com-
ponents that make up the front suspension of E39 cars.
Two different types of steering systems are used in the E39
series. 6-cylinder
(5251,5281 and 530i) models are equipped
with a rack and pinion type steering system mounted to an
aluminum subframe.
V-8 (540i) models use a steering gear-
box type system mounted to a steel subframe.
See
300 Suspension, Steering and Brakes-General for a
description of the front suspension and components, as well
as specifications for setting ride height.
CAUTION-
Some E39 models are equipped with aluminum suspen-
sion components. The foiiowing cautions apply:
Due to the chemical and corrosion characteristics of
aluminum, do not bring into contact with battery acid.
* Do not clean with wire brushes with brass or iron bris-
ties. Only use brushes with stainless steei bristles.
Do not expose to flying sparks from grinding/cutting op-
erations.
* Do not subject to steei welding splashes.
Do not expose to temperatures over 80°C (176°F).
even for short periods. Temperatures in painting faciii-
ties are not a problem.
Special tools
Special service tools are required for most of the work de-
scribed in this repair group. In addition to the tools depicted in
the illustrations, avariety of press tools are necessaryfor con-
trol arm bushing replacement. Read the procedures through
before beginning any job.
31 2 210 I < Strut nut socket
(Tool No. 31 2 210)

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31 0-5
Front ~uspensionl
Front strut assembly, removing and
installing
- Raise car and remove front wheel.
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points.
Do not place jack stands under
suspension
parts.
- Unbolt bralte caliper assembly, lkeeping bralte hose connect-
ed. Secure brake caliper to body with wire. Do not let it hang
from brake hose. See
340 Brakes.
Remove ABS pulse sensor mounting bolts (arrows) and re-
move sensor from housing.
Detach ABS sensor wire harness and bralte pad wear sensor
wire harness (if equipped) from strut housing.
Loosen and remove stabilizer bar link mounting nut while
counterholding
link ball joint. Disconnect stabilizer link from
strut.
NOTE-
Use a thin wrench to counterhold shaft of stabilizer bar link
ball joint.
- Cars equipped with vertical headlight adjustment system:
Disconnect control arm from level sensor.
4 Remove outer tie rod end nut. Use BMW special tool 31 2
240 or equivalent to press tie rod end out of steering arm.

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/~ront Susaension
Front suspension arms FRONT SUSPENSION ARMS
Scyllnder models (5251,5281,530i)
Control arms and tension struts are attached to the front sub-
Front suspension arms V-8 models (5401)
frame through rubber bushings and to the steering ltnuckles
by ball joints.
NOTE-
Tension struts are sometimes called thrust arms or thrust
rods.
Control arms or tension struts are sometimes called lower
front arms or lower rear arms.
Inspect ball joints for wear and looseness. lnspect bushings
for wear or fluid
lealts. The ball joint can only be replaced as
part of an entire suspension arm assembly. Some suspen-
sion arm
bushinas are available as re~lacement Darts. Al-
ways replace in pairs
NOTE-
Steering wheel vibration during braking (usually at road
speeds of
50 to 60 m.p.h.) are often causedby faulty suspen-
sion arm bushings, not out-of-true brake rotors.
Some special tools may be required to remove suspension
arms and to replace bushings. Read procedures through be-
fore beginning the job.
Control arm, removing and installing
(6-cylinder models)
- Raise car and remove wheel
Male sure
that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points. Do not place jack stands under
suspension
parfs.
Cars equipped with vertical headlight adjustment system:
Disconnect control arm from level sensor.
Remove control arm fasteners (arrows). Lightly tap inner
control arm mounting bolt out of subframe.

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Front Suspension
< Use BMW special tool 31 2 240 or equivalent to separate
control arm ball joint from steering ltnuckle.
- When installing control arm, make sure all thread bores.
bolts, nuts and mating surfaces are clean.
- Install bushing end of control arm to subframe, using wash-
ers on both sides of bolt and a new self-locking nut. Do not
tighten nut at this time.
- Install control arm ball joint to steering lknucltle using a new
self-locking nut. Tighten fully.
- Install wheel and lower car.
- Load car to normal loaded position as described under Ride
height. See
300 Suspension, Steering and Brakes-Gen-
eral. Bounce suspension a few times.
- With car on ground and loaded, tighten control arm bushing
through-bolt.
Tightening torques
Control arm to steering ltnuckle
80 Nm (59 ft-lb)
Control arm to subframe 110 Nm (81 It-lb)
Road wheel to hub 120ilO Nm (8957 it-lb)
Control arm, removing and installing
(V-8 models)
- Raise car and remove wheel
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural
cliassis points. Do not place jack stands under
suspension parts.
Loosen and remove stabilizer bar link mounting nut
(A) while
counterholding ball joint
(B). Disconnect stabilizer link from
stabilizer bar.
- Cars equipped with vertical headlight adjustment system:
Disconnect control arm from level sensor.

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1 320 Steering and Wheel Alignment
General ........................... .32 0.2
Special tools
........................ .32 0.2
Steering system
..................... .32 0.4
Steering system variations
............. .32 0.5
Steering system warnings and cautions
... .32 0.6
Steering Wheel .................... .32 0.7
Steering wheel. removal and installation
.. .32 0.7
Steering Column ................. .32 0.1 0
Steering column components .......... .32 0.10
Steering column trim, removing
and replacing
...................... .32 0.10
lgnition switch ring antenna (EWS).
removing and installing
............... .32 0.1 1
lgnition lock cylinder.
removing and installing
............... .32 0-1 1
Steering column lock. removing
and installing
....................... .32 0.12
lgnition
interloclc cable. removing and installing
(models with automatic transmission)
... .32 0.13
Interlock cable. adjusting
(models with automatic transmission)
... .32 0.14
Steering column. removing and installing
. .32 0.14
Steering column adjustment motors.
removing and installing
............... .32 0.16
Power Steering Pump ............. .32 0.17
Power steering pump. removing
and installing
....................... .32 0.1 7
Power steering system.
bleeding and filling
.................. .32 0.18
Rack and Pinion Steering
(6-cylinder models)
............... 320-19
Rack and pinion steering components
(6-cylinder models)
.................. 320-1 9
Steering rack. removing and installing
.... 320-19
Steering
rack boot. replacing ........... 320-22
Tie rod (outer). replacing
.............. 320-22
Tie rod (inner). replacing
.............. 320-23
Steering Gearbox (V-8 models) .... 320-24
Steering gearbox system components
. .
(V-8 models) ....................... 320-24
Steering gearbox, removing and installing 320-25
Pitman arm. removing and installing ..... 320-28
Pitman arm. adjusting ................ 320-29
Steering idler arm. removing
and installing
....................... 320-30
Idler arm bushing. replacing ........... 320-31
Center tie rod. replacing
.............. 320-32
Wheel Alignment .................. 320-33
Camber
........................... 320-33
Caster
............................ 320-33
Front toe and toe difference angle
....... 320-34
Reartoe ........................... 320-34
Preparing for alignment
............... 320-35
Alignment specifications tables
......... 320-35

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I Steering and Wheel Alignment
This repair group covers steering wheel and column removal
and steering system service, including wheel alignment infor-
mation.
NOTE-
Ignition loclc cylinder replacement is covered in this sec-
tion.
a For information on steering column mounted switches, in-
cluding the ignition switch, see
612 Switches.
Special tools
Some special tools are necessary to carry out the repairs and
adjustments required for steering service and wheel align-
ment. Be sure to read the procedures through before starting
work on the vehicle.
4 Steering shafl retaining ring installation tool
(Tool No. BMW 32
1 090)
4 Bail joint removal tool
(Tool No. BMW 32
1 190)
4 Pitman arm removal tool
(Tool No. BMW 32 2
000)
4 Inner tie rod removal tool
(Tool No. BMW 32 2
110)

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I Steerina and Wheel Alianment
Steering
system
Two types of steering gear are used in the E39 series models.
6-cylinder
(5251, 528i and 530i) models are equipped with
rack and pinion steering. The steering rack is mounted to
an aluminum subframe.
V-8
(540i) models are equipped with a recirculating ball
and nut steering gearbox mounted to a steel subframe.
At low speeds, maximum power assist is provided to ease
parking and city driving. At high speeds, assist is reduced to
ensure stability. The power steering system varies assist
based on engine speed.
Power boost for the steering is provided by an engine-driven
hydraulic pump. A hydraulic control valve is used to control
boost pressure.
The steering wheel connects to the steering gear via an ad-
justable steering column which incorporates a rubber cou-
pling ("guibo") to dampen vibration and noise.
Power steering fluid is supplied from the fluid
reservoir to the
pump and to the steering gear via rubberlmetal hoses.
The return line from the steering gear to the
reservoir loops
into the airstream in front of the radiator and connects to the
steering fluid cooler. The fluid cooler is attached to a cassette
which also includes cooling coils for engine oil, transmission
fluid and AIC condenser.
The steering gear requires no maintenance other than align-
ment and periodic inspection for worn components. Inspect
rubber rack boots
(rack and pinion system) and tie-rod end
boots periodically for tears or damage. Replace
if necessary.
-
NOTE-
The airbag system is traditionally referred to as Supplemen-
tal Restraint System (SRS). The
BMW versfon of SRS used
m the E39 models is known as the Multiple Restraint System - (MRS). - -

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Steering and Wheel Alignment
I Rack and r in ion steering 1 Steering system variations
I 6-~~linder'rnodels (525i,>28i, 530i) / 1. Left tie rod
2. Right tie rod
3. Steering rack
4. Steering gearbox
5. idler arm
6. Center tie rod
7. Steering knuckle
Recirculating ball and nut steering
r V-8 models 154Oib

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Steering and Wheel Alignment
Steering system warnings and cautions
WARNING -
The BMW airbag system is complex. Special precautions
must be observed when servicing the system. Serious in-
jury may result if system service is attempted by persons
unfamiliar with the BMW
airbag system and its approved
service procedures. BMW specifies that all inspection and
service should be
peiformed by an authorized BMW deal-
e,:
The BMW E39 is equipped with an airbag mounted in
the steering wheel. The
airbag is an explosive device
and should be treated with extreme caution. Always fol-
low the
airbag removal procedure as outlined in 721
Airbag System (SRS).
BMW airbags are equipped with a bacli-up power sup-
ply inside the
airbag control module. A 5 second wait-
ing period should be observed after the battery cable
has been disconnected. This will allow the reserve
power supply to discharge.
Do not reuse self-locking nuts. They are designed to
be used only once and may fail if reused. Always re-
place them with new locliing nuts.
* Do not install bolts and nuts coated with undercoating
wax, as correct tightening torque cannot be assured.
Always clean the threads with solvent before installa-
tion, or install new parts.
Do not attempt to weld or straighten any steering com-
ponents. Always replace damagedparts.
CAUTION--
- Some E39 models are equipped with aluminum suspen.
sion components. The following cautions apply:
Due to the chemical and corrosion characteristics of
aluminum, do not bring into contact with battery acid.
Do not clean with wire brushes with brass or iron bris-
tles. Only use brushes with stainless steel bristles.
Do
not expose to flying sparks from grindinghutting op-
erations.
Do not subject to steel welding splashes.
* Do not expose to temperatures over 80% (176°F).
even for short periods. Temperatures in painting iacili-
ties are not a problem.

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320-7
Steering and Wheel ~liqnmentl
STEERING WHEEL
Steering wheel, removal and installation
WARNING -
The BMWairbag system (Supplemental Restraint System or
SRS) is complex. Special precautions must be observed
when servicing. Serious injury may result if
SRS system serv-
ice is
attempted by persons unfamiliar with the BMW SRS
and its approved service procedures. BMW specifies that all
inspection andservice should be preformed by an authorized
BMW dealer.
E39 cars may come with either one of two different styles of
steering wheel:
Multifunction (MFL) steering wheel
* Sport steering wheel
4 Multifunction (MFL) steering wheel components:
1. Cruise control 1 radio 1 telephone electrical harness
2. Horn button electrical harness
3. Airbag electrical harness
4. Radio / telephone control switch set
5. Air bag
6. Cruise control switch set
Sport steering wheel
3
5 0021413
4 Sport steering wheel components:
1. Switch carrier
2 Steering wheel switch set electrical harness
3. Airbag
4. Lower cover
5. Horn button and airbag electrical harness
- Center steering wheel. Make sure front wheels are pointed
straight ahead.
- Disconnect negative (-) cable from battery.
CA UTIOP&
Prior to disconnecting the battern read the battew discon-
nection cautions given in
001 General Cautions and
Warnings.
-