1999 BMW 540i Rear suspension

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330-47
Rear suspension/
Ride height sensor, removing and installing
Hall effect sensors for vehicle height detection are mounted
on the
left and right sides of the rear suspension. A coupling
rod mounted between the rear suspension arm and the sen-
sor arm is used to send a varying voltage signal to the
EHC
control module.
Raise car and support safely.
WARNING-
Male 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
sus~ension Darts.
Working underneath rear of car, remove trim panel (arrow)
just ahead of suspension subframe.
Disconnect electrical harness connector from sensor.
4 Remove control rod mounting nut (arrow).Turn control rod to
access sensor mounting fastener.
- Remove sensor mounting fasteners.
- Remove ride height sensor.
- Installation is reverse of removal.
Make sure sensor lever points outward. After assembly, re-
set ride height using BMW diagnostic scan tool DIS.
Tightening torques
Ride
height sensor to bracket 5 Nrn (44 lb-in)
Lever to height sensor
9 Nrn (80 ib-in)

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Final Drive
Final drive, removing and installing
- Raise rear of car.
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place the jaclc stands beneath struc-
tural chassis
~oints. Do not i lace iaclc stands under
( suspension barfs.
Remove exhaust system. See 180 Exhaust System.
Disconnect drive shaft from final drive. See
260 Driveshaft.
Remove drive axle CV joint bolts (arrows) at left and right
sides. Suspend drive axles from body using stiff wire.
4 Support final drive with BMW special tool 33 4 390.
* Remove front final drive mounting bolt.
Remove rear final drive mounting bolts
(2).
Carefully lower final drive unit.
- To install, use BMW special tool 33 4 390 to lift final drive into
place.
CA UTIOP&
The following sequence must be used when installing the fi-
nal drive to prevent torsion stress on the final drive during in-
Install mounting bolts and finger tighten only.
Remove final drive support.
Tighten both rear mounting bolts.
Tighten front mounting bolt.
NOTE-
Use new self-locking nuts.
- Check differential oil level. See Differential oil level, check-
ing.
- Remainder of installation is reverse of removal.

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Final Drive
Drive axles use constant-velocity (CV) joints on both ends.
For replacement parts, only CV joint boots or complete axles
are offered by BMW. The procedure for drive axle removal
varies for sedan and sport wagon. Follow the appropriate pro-
cedure below.
Drive axle assembly
1. lnner CV joint
2. Drive axle
3. Outer CV joint
4. Collar nut
5. Outer CV boot kit
6. lnner CV boot kit
7. Circlip
8. Dust cover
9. Reinforcement
10. Torx bolt
Drive axle, removing and installing (sedan)
4 With an assistant applying brakes, break free staked collar
nut (arrow) at center of rear wheel hub. Do not remove com-
pletely.
NOTE-
The drive flange collar nut is tightened to a torque of over 300
Nm (221 ft-lb). Male sure the car is firmly on the ground.
- Raise rear of car. Remove rear wheel
WARNING -
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place the
jack stands beneath struc-
tural chassis points. Do not place jack stands under
suspension parts.
- Remove f~nal drrve. See Final drive, removing and install-
ing.

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Final ~rivel
4 Remove staked collar nut and press output shafl out of wheel
hub with special
BMW tool 33 2 111/116/117.
- Remove drive axle.
- Installation is reverse of removal, noting the following:
Use a new collar nut.
a Apply a light coating of oil to contact face of collar nut and
install it loosely.
* Install road wheel and lower car to ground.
- With an assistant applying brakes, tighten drive axle collar
nut to its final torque.
Stake collar nut.
Tightening torques
-
Drive axle collar nut to drive flange M27 300 Nrn (221 ft-lb)
Drive axle to differential flange
* M10x20 rnm black Torx bolt
83 Nrn (61 ft-lb)
M10x20 rnrn silver Torx bolt
100 Nrn (74 ft-lb)
Road wheel to hub 120 Nrn f 10 (89 ft-lbf7)
Drive axle, removing and installing
(Sport Wagon)
4 With an assistant applying brakes, brealc free staked collar
nut (arrow) at center of rear wheel hub. Do not remove com-
pletely.
NOJE-
The drive flange collar nut is tightened to a torque of over 300
Nm (221 ft-lb). Make sure the car is firmly on the ground.
WARNING -
Disable airsupply pump (if applicable) by disconnecting elec-
tricalplug before performing any repairs. Pump is located be-
neath a cover under the spare tire
in the floor of the cargo
compartment.
- Raise rear of car. Remove rear wheel.
WARNING -
Malce sure that the car is firmly supported on jack stands de-
signed for the purpose. Place the jack stands beneath struc-
tural chassis points. Do not place jack stands under
suspension parts.
- Models with rear coil springs: Remove cargo compartment
floor carpet.

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E39 brake system
BMW E39 models are equipped with vacuum power-assisted
four-wheel disc brakes with an integral
Antilock Brake System
(ABS). Single-piston calipers act on vented front and rear ro-
tors. A brake pad wear sensor for each axle indicates when
brake pads need replacement. The dual drum-type parking
brake system is integrated with the rear brake rotors.
Electronic braking and stability control
E39 models were introduced with Automatic Stability Control,
a computer controlled traction control system that uses the
AB5 system in conjunction with engine management controls
to control wheel spin during take-off and maintain vehicle sta-
bility while braking.
Added in the
1998 model year was Dynamic Stability Control
(DSC). This system implements wheel speed modulation
throughout all stages of driving. For example, DSC is able to
reduce understeer by applying differing amounts of braking
force to each wheel, or it can override the engine manage-
ment system during hard cornering.
A summary of distinguishing characteristics of the various
systems is shown in the table
E39 electronic braking and
stability control systems.
For ABS, ASC and DSC system and component descriptions,
see
300 Suspension, Steering and Brakes-General.
WARNING-
A car with electronic stability control is still subject to normal
physical laws. Avoid excessive speeds for the road conditions
encountered.
E39 electronic braking and stability control systems
Year (model)
manuf. up to 911998
(528i, 540i)
manuf. from 911999
(540i optional)*
From
911 999
(ail models) System
Automatic Stability Control (ASC) Identifiers
Electronic control module next to glove compartment
Hydraulic unit in right rear of engine compartment
No precharge pump
Dynamic Stability Control
(Bosch DSC
Ill v. 5.3)
Dynamic
Stabil~ty Control
(Bosch DSC
Ill v. 5.7) Electronic
control module next to glove compartment
Hydraulic unit in right rear of engine compartment
Precharge pump in left front of engine compartment, below steering
fluid reservoir
Separate rotational rate (yaw) and lateral acceleration sensors
Control
modulelhydraulic unit in right rear of engine compartment
No precharge pump
Combined rotational rate (yaw) and lateral acceleration sensors

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340-6
1 Brakes
Brake system troubleshooting
/symptom I Probable cause 1 Repairs
Brake squeal
Pedal goes to floor when
bralting
Low pedal after system bleeding
Pedal spongy or brakes work
only when pedal is pumped
Excessive braking effort
Brakes pulsate, chatter or grab
Uneven
bralting, car pulls to one
side, rear braltes
loclt
Brakes drag, bind or overheat Brake
pad carriers dirty or corroded or
pads loose (poor fit) in pad carrier
Braite pads heat-glazed or oil-soaked
Wheel bearings worn (noise most
pronounced when turning)
Incorrectly Installed brake pads,
parking bralte shoes, or bralte parts
Brake fluid loss due to system leaks
Master cylinder or traction control
system faulty
Master cylinder faulty
Air in braite fluid
Master cylinder or traction control
system faulty
Brake pads wet
Brake pads
heat-glazedorfluid-soalted
Vacuum booster or vacuum hose
connections to booster faulty
--- Warped brake rotors
Brake pads worn
Brake pads heat-glazed or oil-soaked Remove
brake pads and clean calipers. Use original
equipment pads for proper fit and use BMW anti-squeal
compound during installation,
Replace brake pads. Ciean rotors. Replace leaking caliper:
as required.
Replace worn bearings. See 310 Front Suspension
or33C
Rear Suspension.
Check component installation. Checldreplace anti-rattle
springs.
Checlt fluid level and inspect for signs of leakage.
Replace master cylinder. Diagnose traction control system
using factory or compatible diagnostic tool.
Replace master cylinder.
Bleed system using factory or compatible diagnostic tool.
Replace master cylinder. Diagnose traction control system
using factory or compatible diagnostic tool.
Use light pedal pressure to dry pads while driving.
Replace
bralte pads and rotors. Replace leaking calipers.
lnspect vacuum lines. Test vacuum booster and replace as
required. Test vacuum non-return valve for one-way flow.
Resurface or replace rotors.
Replace brake pads.
Clean rotors. Replace leaiting calipers.
Incorrect tire pressures or worn tires
Brake pads on one side of car heat-
glazed or fluid-soaked
Caliper or brake pads binding
Worn suspension components
Brake caliper or brake pads binding
Master cylinder or traction control
system faulty lnspect
tire condition. Checlt and correct tire pressures.
Replace brake pads. Clean rotors. Replace leaking
calipers.
Clean and recondition brakes.
Inspect for worn or damaged suspension components. See
310 Front Suspension or 330 Rear Suspension.
Ciean or replace caliper.
Replace master cylinder. Diagnose traction control system
using faclory or compatible diagnostic tool.

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340-1 2
Brakes Brake pads, checking and replacing
Brake pads can be replaced without disconnecting the brake
fluid hose from the caliper or having to bleed the brakes. The
rotors can be replaced without disassembling wheel hub and
bearing. Always machine or replace rotors in pairs. Replace
pads in sets.
Front and rear brake pad replacement procedures are identical.
WARNING -
* Altllough semi-metallic andmetallic brale friction materials
in brake pads or shoes no longer contain asbestos, they
produce dangerous dust.
Treat all
brale dust as a hazardous material.
Do not create dust by grinding, sanding, or cleaning
brake friction surfaces with compressed air.
CAUTION--
Pressing caliper piston in may cause brake fluid reservoir to
overflow To prevent this, use a clean syringe to first remove
some fluid
from reservoir.
Raise car and remove wheels,
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands beneath structural
chassis points. Do not place jack stands under suspension
parts.
/ 4 To measure brake pad lining thickness, insert BMW special
n 1 tool 34 1 260 at either frontilght wheel or left rear wheel -
Move wheel until notch for brake wear indicator can be
seen through wheel opening.
Insert tip of tool into notch so that the body of tool rests on
brake pad backing plate
(A), and tip touches bralte disc
(B).
Replace pads if thickness is 3.0 mm (0.12 in) or less.
Pry off
bralte calipe~ , anti-rattle spring (arrow).

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340-1 5
Brakes
- Remainder of installation is reverse of removal.
- Clean brake caliper mounting bolts (7 mm Allen). Replace
ones which are not in perfect condition. Do not grease.
Top up brake fluid to MAX marking.
- Before driving car, pump bralte pedal several times so that
brake pads contact brake rotors.
Check that brake fluid level is correct. Top up if necessary.
Hold ignition key for at least
30 seconds in accessory po-
sition without starting engine. This clears any fault codes in
memory and turns off brake pad warning light.
Tightening torques Brake caliper to pad carrier
(7 mm Allen)
Front caliper
30 Nm (22 It-lb)
- Rear caliper 28 Nm (21 It-lb)
Road wheel to hub
120i 10 Nm (89i7 ft-lb)
Brake rotors, removing and installing
- Raise car and remove wheels
WARNING-
Male sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands beneath structural
chassis points. Do not place jack stands under suspension
parts.
Remove brake caliper carrier bolts (arrows). Suspend brake
caliper from chassis using stiff wire.
NOTE-
Hydraulic brake line remains connected.
4 Remove bralte rotor mounting screw (arrow) and remove ro-
tor.
- Inspect rotor for cracks, signs of overheating and scoring.
- Minimum allowable thickness (MIN TH) is stamped on rotor
hub. Measure rotor braking surface with a micrometer at
eight to ten different points and use the smallest measure-
ment. Compare to specifications in table below.
- If rotor does not pass minimum thickness requirements or is
damaged, replace rotor.