1999 BMW 528i rear shock

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300-5
Suspension, Steering and Brakes - ~enerall
The E39 rear suspension subframe is used as a rigid mount-
ing platform
forthe differential (also called final drive) and rear
suspension components. The differential is mounted to the
subframe and the subframe is bolted to the body through rub-
ber bushings which help isolate drivetrain noise and vibration.
The
€39 rear suspension is known as a modified multi-link
system. Three control arms on each side locate the rear
wheels.
The lowercontrol arm, called the swing arm, is attached to the
wheel bearing carrier through a pivoting integral link.
An eccentric mounting bolt at the rear inner mounting of the
swing arm is used for rear camber adjustment.
The inner end of the upper front control arm, called the trac-
tion strut, is also mounted with an eccentric fastener, used to
adjust rear toe.
Drive axles with constant-velocity (CV) joints at both ends
transfer power
from the differential to the road wheels.
Sedan models
The rear suspension in sedan models uses coil springs over
strut shock absorbers. The bottom of each strut bolts to the
wheel
carrier.The top strut mount attaches just below the rear
parcel shelf of the car.
Sedan models fitted with EDC (Electronic Dampening Con-
trol) use air struts.

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Suspension, Steering and Brakes - General
Rear suspension Sport Wagon
(with coil springs)
Shock absorber 1

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300-8
Suspension, Steering and Brakes - General
Rear suspension Sport Wagon
(EHC with air springs)
Air sprIn9 Shock absorber I
(tiaction strut) arA
(lower control arm) Integral arm 502330210
EHC initiates a control sequence as necessary. The system
offers the following features:
Control system independent from vehicle engine (no en-
gine driven hydraulic pump system)
Individual control of rear wheels
Uneven load identified and compensated for
Uneven road surfaces identified and not compensated for
Automatic control interrupted when cornering
System diagnosable using the
BMW Service Tester (DIS-
plus, GTI, or MoDiC)

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330 Rear Suspension
General . . . . . . . . . . . . . . . . . . . . . . . . . . . ,330-2
Special tools . . . . . . . . . . . . . . . . . . . . . . . . ,330-2
Rear suspension variations . . . . . . . . . . . . ,330-4
Rear Struts and Springs
(sedan models)
. . . . . . . . . . . . . . . . . . . . ,330-5
Rear strut assembly, removing
and installing
. . . . . . . . . . . . . . . . . . . . . . . ,330-5
Rear strut assembly, disassembling
and assembling
. . . . . . . . . . . . . . . . . . . . . ,330-7
Rear Shock Absorbers and
Springs (Sport Wagon models)
. . . . . ,330-9
Rear shock absorber, removing
and installing
. . . . . . . . . . . . . . . . . . . . . . . ,330-9
Coil spring, removing and installing . . . . . ,330-1 1
Air spring, removing and installing
. . . . . . ,330-12
Rear Suspension Arms,
Subframe and Bushings . . . . . . . . . . ,330-13
Rear suspension arm components . . . . . . ,330-1 3
Swing arm, removing and installing (sedan models)
. . . . . . . . . . . . . . . . . . . . . ,330-1 4
Swing arm, removing and installing (Sport Wagon models)
. . . . . . . . . . . . . . . ,330-16
Swing arm ball joint, replacing . . . . . . . . . ,330-1 9
Upper rear control arm, removing
and installing (sedan models)
. . . . . . . . . . .330-22
Upper rear control arm, removing
and installing (Sport Wagon models)
. . . . .330-23
Upper front control arm (traction strut),
removing and installing
. . . . . . . . . . . . . . . ,330-25
Rear axle assembly, removing and
installing (sedan models)
. . . . . . . . . . . . . ,330-26
Rear axle assembly, removing and
installing (Sport Wagon models)
. . . . . . . ,330-28
Rear subframe mounting bushings,
removing and installing
. . . . . . . . . . . . . . . .330-31
Rear Wheel Bearings . . . . . . . . . . .
Rear wheel bearing carrier, removing
and installing (sedan models)
. . . . . . .
Rear wheel bearing carrier, removing
and installing (Sport Wagon models)
. .
Rear wheel bearing, replacing . . . . . . .
Rear Stabilizer Bar
Stabilizer bar, removing and installing .
Stabilizer bar link, removing
and installing
. . . . . . . . . . . . . . . . . . . .
Electronic Height Control (EHC)
Component Replacement
. . . . . . .
Electronic height control (EHC)
components
.....................
Air compressor pump relay, removing
and installing
. . . . . . . . . . . . . . . . . . . .
EHC control module, removing
and installing
. . . . . . . . . . . . . . . . . . . .
Air supply unit, removing and installing
Ride height sensor, removing
and installing
. . . . . . . . . . . . . . . . . . . .

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330-4
Rear Suspension Rear suspension variations
1. Coil spring
2. Strut
3. Final drive (differential)
4. Rear subframe
5. Upper rear control arm
(wishbone)
6. Subframe mounting bushing
7. Drive axle
8. Upper front control arm
(traction strut)
9. Swing arm (lower control arm)
10. Integral link
12. Air spring
I
Waaon
11. Shockabsorber
a m3 withair s~riias

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Rear ~us~ensionl
Rear strut assembly, disassembling and
assembling
Replace struts and coil springs in pairs only
Replacing the upper strut mount, spring or strut requires that
the strut assembly first be removed from the car, as described
earlier. Strut disassembly requires a spring compressor.
WARNING-
Do not attempt to disassemble the strut without a spring com-
pressor designed specifically for the job.
- Remove strut assembly from car as described in Rear strut
assembly, removing
bnd installing
4 Mount spring compressor (BMW special tools 31 3 340 and
31 3 350 or equivalent) in shop vice. Install correct-sized
spring retainers
(A).
WARNING-
Do not attempt to disassemble the struts without a spring
compressor designed specifically for this job.
* Prior to using the spring compressor checlc its opera-
tion. Do not use a spring compressor that is damaged.
Do not make any modifications to the spring compres-
sor.
Never use an impact wrench to compress or relieve
tension when using a spring compressor.
1
- Place strut assembly coil spring in spring retainers. Com-
press spring until force on upper strut mount is relieved.
Remove strut top mount self-locking nut with BMW special
tool
31 2 21 0 while counterholding strut shaft with a box end
wrench.
- Remove upper strut mount and related components. Sepa-
rate strut from spring.
NOTE-
Store the removed shock absorber upright Do not allow it to
lie horizontally or upside down for any length of time. If incor-
rect storage has occurred, place the
shoclc absorber upright
with the rod
fully extended for at least 24 hours.
- Replace strut, rubber bumper, upper strut mount or spring,
as needed.
NOTE- Relieve tension on spring compressor slowly and carefully.
Fit new spring in spring compressor so that one coil at
each end is outside spring retainer.

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330-8
Rear Suspension
4 Compress spring and install it and related components to
shock absorber. Use new self-locking upper strut mounting
nut.
1. Upper strut mount self-locking nut
2. Washer
3. Poor road surface adapter
4. Upper spring seat
5. Upper strut mount
6. Upper rubber bumper seat
7. Rubber bumper
8. Coil spring
9. Dust boot
10. Lower spring seat
I I. Strut
WARNING-
Male sure the upperself-locking nut is fully tightened before
releasing the spring compressor.
Tightening torque
Upper strut mount to strut shaft
27 Nm (20 ft-lb)
(M14, replace self-locking nut)
4 Before releasing spring tension, position upper strut mount
so that one threaded stud is on a plane with flat end of strut
bushing at other end of strut.
- Release spring compressorslowly, positioning spring ends in
shoulders of spring seats.
- Reinstall strut assembly in vehicle, as described above in
Rear strut assembly, removing and installing.

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C. -- -- - -- Rear ~us~ensionl
Depending on year and model applications, the Sport Wagon
rear suspension may be equipped with:
Conventional shock absorbers and coil springs
Electronic height control (EHC) system which incorporates
air springs
NOTE-
. Suspension and EHC troubleshooting is covered in 300
Suspension, Steering and Brakes-General.
EHC system repairs, other than air spring replacement,
are covered in Electronic height control
(EHC) compo-
nent replacement.
Replace shock absorbers and springs in pairs only.
Rear shock absorber, removing and
installing
- Raise car and remove rear wheels,
WARNING-
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 parts.
CAUTION-
If working on a vehicle with compressedairshock absorbers,
disable air supply pump by disconnecting electrical plug be-
fore performing any repairs. Pump is located beneath a cover
under the spare tire in the floor of the cargo compartment.
- Support swing arm from below
CAUTIOG
The shock absorber prevents the drive axle and wlieel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting fasteners prevents damage to the
brake hose,
parking
brake cable and drive axle CVjoints.
- Working in cargo compartment, remove carpet. Remove tri-
angular upper shock mount covers located beside spare tire
well.
- If applicable: Detach air supply line from shock absorber.
Plug ports and lines to keep out dirt.