1999 BMW 525i Workshop Manual

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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.

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330-1 0
/Rear Suspension
- Remove rubber protective cap from shock absorber upper
mount.
- Remove shock absorber upper mounting nuts.
- Remove shock absorber lower mounting bolt. Lower shock
absorber out of wheel housing.
< Transfer shock top mounting plate, dust cover (if applicable)
and related components to new shoclc absorber.
1. Self-locking nut
2. Washer
3. Upper siioclc absorber mount
4. Rubber bumper seat
5. Rubber bumper
6. Dust boot
7. Shock absorber
8. Long lower bushing
Tightening torques
Shock absorber to upper mount
27 Nm (20 it-lb)
(M14, replace self-locking nut)
- Installation on car is reverse of removal, noting the following:
Make sure all threaded bolts, nuts and mating surfaces are
clean.
Install shock absorber upper mount to
subframe using new
self-locking nuts.
. Make sure long lower shock absorber bushing fits in hole
in suspension swing arm.
Tighten lower shoclc absorber bolt to its final torque once
car is on ground.
Tightening torques
Quick coupling screw to air 2 Nm (18 in-lb)
shock absorber
Road wheel to
hub 120 &I0 Nm (89 -f7 ft-lb)
Shock absorber to swing arm 127 Nm (94 ft-lb)
Strut mount to body
Gray fasteners
Yellow fasteners
24 Nm ( 18 it-lb)

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330-1 1
Rear Suspension
Coil spring, removing and installing
Raise car and remove rear wheels.
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.
- Remove brake caliper and brake disc. Hang brake caliper
aside with stiff wire. Do not disconnect
bralte fluid hose. See
340 Brakes.
- Remove exhaust system. See 180 Exhaust System.
- Disconnect driveshafl from final drive. See 260 Driveshaft.
- Detach parking bralte cables from mounting bracltets on sub-
frame.
< Support final drive unit from below using transmission jack
and
BMW special tool 33 4 390 or equivalent.
Remove rear suspension
subframe mounting bolts (arrows).
Lower rear
subframe until coil springs can be removed.
When reinstalling springs, replace upper and lower spring
pads if necessary.
Slowly lift suspension
back into position, making sure coil
springs are correctly seated in upper and lower spring seats.
Install and tighten
subframe mounting bolts. Note that on
each bolt, rubber-coated detent plate (arrow) must be in-
stalled at rear in driving direction
- Remainder of installation is reverse of removal
Tightening torques Road wheel
to hub 12OilO Nm (89i-7 ft-lb)
Subframe to body 163 Nm (120 ft-lb)

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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 ~us~ensionl
Remove fasteners A, B and C while supporting swing arm
from below.
Carefully pry swing arm away from mounting points, while
continuing to support from below.
Remainder of installation is reverse of removal, noting the fol-
lowing:
Use new self-locking nuts.
lnstall bolt
(C) through bracket and arm. Install and tighten
nut finger tight.
Install bolts
(A) and (6). Install and tighten nuts finger tight.
Line up eccentric camber adjusting bolt with marlts made
previously.
Tighten fasteners to final torque only after vehicle has
been lowered and suspension has settled.
Have car professionally aligned when job is complete.
Tightening torques
ABS pulse sensor to wheel bearing carrier 8 Nm (6 ft-lb)
Road wheel to hub
120+10 Nm
(89
i-7 ft-lb)
Stabilizer link to swing arm 65
Nm (48 ft-lb)
Swing arm to rear
subframe
(camber bolt M12) (A)
115 Nm (85 ft-lb)
Swing arm to rear
subframe (B) 58 Nm (43 ft-lb)
Swing arm
to wheel bearing carrier (C) 256 Nm (189 ft-lb)

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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.