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300-1 0
/Suspension, Steering and Brakes - General
The steering system features variable power assist provided
by an engine-driven hydraulic pump.
Rack and pinion steering
6-cylinder models
(525i, 5281, 5300
Two types of steering systems are used in E39 models. 6-
cylinder (525i, 5281, 530i) models are equipped with a steer-
ing rack system. V-8
(540i) models are equipped with a re-
circulating ball and nut steering gearbox.
Rack-and-pinion steering
Steering components in 6-cylinder models consist of a rack-
and-pinion type steering gear and connecting linltage to the
road wheels.
The steering linkage connects the rack-and-pinion unit
through tie rods to the steering knucltles. The tie rod ends al-
low the wheels to pivot and react to suspension travel.
Recirculating ball and nut steering
V-8 models
(540i)
I
Recirculating ball and nut steering
Recirculating ball and nut steering in V-8 models consists of a
steering box with integrated hydraulic control valve and con-
necting linkage to the road wheels.
Thesteering linkageconnects the steering gearbox through a
pitman arm to the wheels. An idler arm maintains correct toe
angle. The tie rod allow the wheels to pivot and react to sus-
pension travel.
E39 cars are equipped with power disc brakes with integral
antilock brakes (ABS). The parking bralte is a dual-drum sys-
tem integrated with the rear brake rotors.
Power assist is provided by a vacuum booster when the en-
gine is running. The brake pedal
pushrod is connected direct-
ly to the master cylinder, so failure of the vacuum booster
does not normally result in total
bralte failure.
Each disc bralte uses a caliper with a single hydraulic cylin-
der. Brake pads in the left front and right rear contain wear
sensors. When brake pads need replacement, the sensors il-
luminate a light on the dashboard.
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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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310-1 5
Front ~us~ension/
4 Remove control arm fasteners (arrows). Lightly tap inner
control arm mounting bolt out of subframe.
Use
BMW special tool 31 2 240 or equivalent to separate ball
joint from steering knuckle.
When installing control arm, make sure all thread bores,
bolts, nuts and mating surfaces are clean.
lnstall bushing end of control arm to subframe, using wash-
ers on both sides of bolt and a new self-loclting nut. Do not
tighten nut at this time.
lnstall control arm ball joint to steering knuckle, using new
self-locking nut. Tighten fully.
- Slide strut back into position and tighten strut pinch bolt 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 knuckle 80 Nm
(59 ft-lb)
Control arm to
subframe 78 Nm (58 ft-lb)
Road wheel to hub
120
f 10 Nm (89 +7 ft-lb)
Stabilizer bar
link to stabilizer bar
59 Nm (44 fl-lb)
Strut pinch bolt
81 Nm (60 it-lb)
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I Rear Suspension
4 When installing subframe bushing, be sure alignment arrows
point front and rear.
Coat new mount with
CircolightB anti-friction agent.
< Draw new bushing into subframe using BMW special tools 33
4152,334153,334154,334155,334157.
- Remainder of installation is reverse of removal, noting the fol-
lowing.
* Tighten suspension arm and shock absorber fasteners to
final torque only after vehicle has been lowered and
sus-
oension has settled.
Rear wheel bearing carrier, removing and
installing (sedan models)
- Raise rear end of car and remove wheel
WARNING-
Make sure the car is firmly supported on jaclc stands de-
signed for the purpose. Place
jaclc stands underneath struc-
tural chassis points. Do not place jaclc stands under
suspension parts.
4 With an assistant applying brakes, break free and remove
staked collar nut (arrow).
- Remove brake caliper and brake disc. Hang brake caliper
aside with stiff wire. Do not disconnect brake fluid hose. See
340 Brakes.
- Disconnect parking brake cable from brake shoe expander.
See 340 Brakes.
Page 730 of 1002
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(Rear Suspension
< Remove upper front control arm (traction strut) ball joint
mounting nut
(arrow). Press control arm ball joint out of
wheel bearing carrier.
- Repeat above process on upper rear control arm.
- Remove wheel bearing carrier assembly.
4 When reinstalling, pull axle shaft through wheel bearing car-
rier using
BMW special tools 33 2 115, 33 2 116 and 33 2
118.
- Lightly oil bearing surface of axle collar nut and install. T~ght-
en collar nut firmly, but do not fully tighten it at this time.
WARNING-
For safety reasons, the ale collar nut should only be tight-
ened to its final torque with the wheel installed and the car
lowered to
the ground. However, loading the bearing without
the nut tightened sufficiently may damage tlie bearing.
Page 734 of 1002
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I Rear Suspension
4 Press out axle shaft using BMW special tools 33 2 117. 33 2
116and332111.
4 Remove upper front control arm (traction strut) ball joint
mounting nut (arrow). Press control arm ball joint out of
wheel bearing carrier.
- Repeat above process on upper rear control arm.
- Remove wheel bearing carrier assembly.
4 When reinstalling, pull axle shafl through wheel bearing car-
rier using BMW special tools 33
2 115, 33 2 116 and 33 2
118.
- Lightly oil bearing surface of axle collar nut and install. Tight-
en collar nut firmly, but do not fully tighten it at this time.
WARNING-
For safety reasons, the axle collar nut should only be tight-
ened to its final torque with the wheel installed and the car
lowered to the ground. However, loading the bearing without
the nut tiqhtened
suificiently may darnaqe the bearina.