1998 BMW 528i ECT

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Rear Suspension
Air spring, removing and installing
CAUTION-
If vehicle is driven with airspring depressurized, the airspring
will be permanently damaged and must be replaced.
An air spring is made from a flexible rubber material which
forms an airtight cavity. It is pressurized by an air supply
pump activated by an electronic control unit to provide a
vari- . . able spring rate depending on vehicle load
CAUTIOIG
Disable air supply pump by disconnecting electrical plug
before performing any repairs. Pump is located beneath a
cover under the spare tire in the floor of
the cargo compart-
ment.
When removing and installing air connections, extreme
cleanliness must be followed. Small dirt particles can
cause leakage in the system.
Remove luggage compartment floor mat.
- Working above air spring, loosen quick coupling screw con-
nection to allow
air pressure to escape.
- Once pressure has been reduced, retighten screw.
Tightening torque Quick coupling screw
to air pump 2 Nm (18 in-lb)
- Remove quick coupler. Plug openings to keep dirt out,
- Remove air spring mounting clips.
- Raise car and remove rear wheels.
Make sure the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points. Do not place
jaclc stands under
suspension parts.
- Working underneath rear suspension, lift wheel bearing car-
rier to relieve rear spring tension. Then unbolt air spring
mounting bolt from seat on wheel bearing carrier. Remove air
spring.
NOTE-
Left and right air springs are different. The left air spring is
marked with a red identification
marl. The right air spring is
marked with a blue identification mark.

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330-1 3
Rear Suspension
1 1 4 Check roll fold of air spring (arrows). Reinstall only if roll fold
is undamaged and formed correctly.
- To install air spring:
Check sealing O-rings at air spring inlet. Replace
if dam-
aged. Do not grease O-rings. Reinstall protective plug.
* Install spring above suspension subframe. Make sure ec-
centric lug at bottom of air spring fits in recess of
subframe
spring seat.
Reattach top spring mounting clips.
- Reattach air line connections.
- Remainder of installation is reverse of removal.
Tightening torques
Air line connection
2 Nm (1 8 in-lb)
Air spring
to wheel bearing carrier 20 Nm (1 5 ft-lb)
Road
wheel to hub 120 510 Nm (89-F-7 ft-lb)
REAR SUSPENSION ARMS,
SUBFRAME AND BUSHINGS
A damaged suspension arm orworn bushings will change the
rear wheel alignment and may adversely affect handling and
stability.
WARNING-
Do not attempt to straighten a damaged suspension arm.
Bending or heating may
weaken the original part. Always re-
olace a damaoed susoension arm.
Rear suspension arm
components
1. Eccentric washer
(for rear toe adjustment)
2. Upper front control arm
(guide link or traction strut)
3. Outer swing arm bushing and
integral link
4. Swing arm (lower control arm)
5. Upper rear control arm
(wishbone)
6. Wheel bearing carrier
7. Circlip
8. Swing arm ball joint
9. Eccentric washer
(rear camber adjustment)

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[Rear Suspension Swing arm, removing and installing
(sedan models)
CAUTION-
If working on a vehicle with compressed airshock absorbers,
disable air supply pump by disconnecting electrical plug be-
fore performing any repairs.
- Raise rear end of car and remove wheel
WARNING-
Make sure 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
sus~ension Darts.
- Disconnect control rod for ride height sensor if applicable.
Remove
ABS pulse sensor (arrow) from wheel bearing car-
rier.
Remove stabilizer bar link mounting nut
(arrow). Press link
out of swing arm.
4 Mark location (arrow) of rear camber adjustment washer and
bolt.
NOTE-
Rear camber is adjusted at the inner swing arm eccentric
rear mounting bolt
- Support wheel bearing carrier from below.

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Rear Suspension Swing arm, removing and installing
(Sport Wagon models)
- Raise rear end of car and remove wheel.
WARNING -
Make sure 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.
CAUJION-
Model with air springs: Disable air supply pump by discon-
necting electricalplug
beforeperforminganyrepairs. Pump is
located beneath a cover under the spare tire in the floor of the
cargo compartment.
< Model with air springs: Loosen compressed air pipes (ar-
rows) at air distribution assembly to release system pres-
sure.
NOJE-
Vehicle will stand quite low
- If applicable: Detach air supply line from shock absorber.
Plug ports and lines to
lkeep out dirt.
- Model with rear coil springs: Remove cargo compartment
floor carpet.
4 Working at top of coil spring, press center cap down or pry
upward to remove. If pushed down, remove from inside coil
spring from under car.
4 Working from underneath, position BMW special tool
33
2 301 between 2nd and 3rd spring coil from bottom.
Make sure tool recess faces upward.
Working in cargo compartment, guide BMW special tool
33
2 304 from above and thread into special tool 33 2 301.

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Rear ~us~ensionl
Working in cargo compartment, attach BMW special tools
33 2 302,33 2 303 and 33 2 305 to special tool 33 2 304.
Use special tool 33 2 306 to compress spring.
Tighten until lower spring coil lifts off spring seat on wheel
bearing carrier.
- Disconnect control rod for ride height sensor if applicable.
4 Remove ABS pulse sensor (arrow) from wheel bearing car-
rier.
- Support wheel bearing carrier from below.
CAUTION-
The shock absorberprevents the drive axle and wheel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting fastenerprevents damage to the
brake hose, park-
ing brake cable and drive axle
CVjoints.
- Remove shock absorber lower mounting bolt
4 Remove stabilizer bar link mounting nut (arrow). Press link
out of swing arm.
4 Mark location (arrow) of rear camber adjustment washer and
bolt.
NOTE -
Rear camber is adjusted at the inner swing arm eccentric
rear mounting bolt.

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330-1 9
Rear suspension1
Swing arm ball joint, replacing
- Raise rear end of car and remove wheel.
Make sure 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.
- Sport Wagon model: Support wheel bearing carrier from be-
low.
CA
UTION-
The shock absorberprevents the drive axle and wheel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the
shoclc absorber
mounting fastenerprevents damage to the brake hose, park-
ing
brake cable and drive axle CVjoints.
- Model with air shock absorbers: Detach air supply line from
shoclc absorber. Plug ports and lines to keep out dirt.
- Sport Wagon model: Remove shock absorber lower mount-
ing bolt.
4 Remove stabilizer bar link mounting nut (arrow). Press link
out of swing arm.
Model with air springs: Disable air supply pump by discon-
necting electrical plug before performing any repairs. Pump is
located beneath a cover under
the spare tire in the floor of the
carao
comoartment.
4 Model with air springs: Loosen compressed air pipes (ar-
rows) at air distribution assembly to release system pres.
sure.
WARNING-
Vehicle will lower when the air pipes are opened.
- Models with rear coil springs: Remove cargo compartment
floor carpet.

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330-23
Rear Suspension
Remove rear control arm:
Remove inner control arm bolt
(A).
Detach plastic wiring harness support (B).
* Remove outer control arm ball joint nut (C). Press ball joint
out of rear wheel bearing carrier.
Installation is reverse of removal, noting the following:
Always use new self-locking nuts.
Malte sure all threaded bolts, nuts and mating surfaces are
clean.
Inner control arm mounting bolt must thread to rear (bolt
head at front).
Tighten fasteners to final torque only afler vehicle has
been lowered and suspension has settled.
Have car professionally aligned when job is complete.
Tightening
torques
Control arm to subframe (M12) 110 Nm (81 ft-ib)
Control arm
ball joint to wheel bearing 142 Nm (105 ft-lb)
carrier
(M14)
Quick coupling screw to air shock absorber
2 Nm (18 in-lb)
Road wheel
to hub 120-flONm
(89 i7 ft-lb)
Upper rear control arm, removing and
installing (Sport Wagon models)
CAUTIOG
Disable air supply pump by disconnecting electrical plug be-
fore
perlorming any repairs. Pump is located beneath a cover
under the spare tire in the floor of the
carqo compartment.
- 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 jack stands under
suspension parts.
Models with rear coil springs: Remove cargo compartment
floor carpet.
Worlting at top of coil spring, press center cap down or pry
upward to remove. If pushed down, remove from inside coil
spring from under car.

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330-24
Rear Suspension
4 Working from underneath, position BMW special tool 33 2
301 between 2nd and 3rd spring coil from bottom.
Make sure tool recess faces upward.
Working in cargo compartment, guide BMW special tool 33
2 304 from above and thread into special tool 33 2 301.
4 Working in cargo compartment, attach BMW special tools 33
2 302, 33 2 303 and 33 2 305 to special tool 33 2 304.
Use special tool 33
2 306 to compress spring.
Tighten until lower spring coil lifts off spring seat on wheel
bearing carrier.
4 Models with air springs: Loosen compressed air pipes (ar-
rows) at air distribution assembly to release system pres-
sure.
WARNING -
Vehicle will lower when the air pipes are opened. 1
- Support wheel bearing carrier from below.
CAUTION-
The shock absorber prevents the drive axle and wheel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting iastenerprevents damage to the brake hose,
parl-
ino brake cable and drive axle CV ioints.
- Models with air shock absorbers: Detach air supply line from
shock absorber. Plug ports and lines to keep out dirt.
- Remove shoclc absorber lower mounting bolt