rear brake BMW 540i 1997 E39 Repair Manual

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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.

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1 Brakes
Max. machine limit per
friction ring side 0.8 mm (0.03
in) I
Brake rotor reconditioning specifications
Model
Replace
braite rotors in pairs
Bralre rotor sizes
Clean rotor with brake cleaner before installing.
Front
Model
6-cylinder
models (5251,
5281, 530i)
V-8 models (540i)
* When installing new rear brake rotors, adjust pariting brake
as described later, in Parking brake, adjusting. Rear
Vented rotor wear limit (min. thickness)
Tightening torques
Braite rotor to hub 16 Nm (12 ft-lb)
6-cylinder models
(525i, 5281, 530i)
- V-8 models (540i)
Front
296 mm (1 1.65 in)
324 mm (12.76 in)
Front bralte pad
carrler to steering ltnucitle 110 Nm (81 ft-lb)
Rear
298 mm (1 1.73 in)
Rear
brake pad carrier to wheel bearing carrier 65 Nm (48 ft-lb)
20.4
mm (0.80 in)
28.4 mm (1.12 in)
Road wheel to hub
120ilONm
(89 -t 7 it-lb)
18.4 mm (0.72 in)
The brake master cylinder is mounted to the front of the vacu-
um booster on the driverside bullthead.
-
CAUTION-
All E39 vehicles soldin the USA are equipped with Antilock
Braling System (ABS) and either Automatic Stability Control
(ASC) or Dynamic Stability Control (DSC).
In order for the
braling and stability controls to work properk if the brake
master cylinder is replaced, make sure that the brake system
is bled
by an authorized BMW dealer or other qualified repair
facility
using the BMW Service Tester. See Brake Bleeding
earlier
in this group.

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Brakes
Master cylinder, removing and installing
CAUTlOI\C
Brake fluid is highly corrosive and dangerous to the environ-
ment. Dispose of it properly.
4 Remove left side interior ventilation microfilter housing:
Remove upper cover and microfilter locking clip
(A).
- Release locking clamp (B), and rotate air tube in direction
of arrow to remove.
Disconnect wiring harness from hood switch
(C).
Release filter body mounting clamp (D) and remove lower
microfilter housing.
4 Remove side trim panel from left rear of engine compartment
by releasing clips
(arrows).
4 Disconnect bralte fluid level sensor connector (A) from fluid
reservoir. Remove reservoir cap.
. Using a clean syringe, empty bralte fluid reservoir.
Where applicable, disconnect hydraulic clutch system sup-
ply line from fluid reservoir duct
(5). Keep supply line sup-
ported and above clutch master cylinder to prevent air
bubbles from reaching clutch hydraulic system.
Where applicable, disconnect DSC system precharge
pump supply line from fluid reservoir duct
(C). Secure sup-
ply line in vertical position to prevent fluid loss.
Plug open brake fluid lines and ducts to prevent fluid leak-
age or contamination.
- Remove brake fluid reservoir by tilting sideways.

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Brakes
Parking brake components
1. Clamp
2. Parking brake cable
3. Cable bracket
4. Grommet
5. Adjusting screw
6. Support
7. Shoe expander
8. Return springs
9. Parking brake shoe
10. Lock down spring
11. Shoe retaining pin
12. Adjuster
Parking brake, adjusting
The parking brake is a brake drum system integrated into the I
rear brake rotors. It can be adjusted with the wheels installed,
although the rear wheels will have to be raised off the ground.
- Adjusting the parking bralte becomes necessary under the
following circumstances:
After replacing parking bralte shoes
After replacing rear brake rotors
Excessive stroke of parking brake handle required for ac-
tuation (more then
10 clicks)
After replacement of brake shoe adjuster or parking bralte
cable(s)
- Lift parking brake lever boot out of console. While holding ca-

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340-23
Brakes
- Using flat-bladed screwdriver, reach into brake drum through
lug bolt hole. Turn brake adjuster until wheel no longer turns.
Back adjuster off
12 notches.
Parking brake adjusting (initial)
Back
off adjuster through wheel
lug bolt hole 12 notches
- Working inside car, set parking brake several times to seat
cable. Then pull parking brake
lever up two notches. Tighten
cable adjusting nuts until it is just possible to turn rear wheels
with slight resistance.
- Release lever and make sure rear wheels turn freely
- Turn on ignition. Pull up parlting brake lever 1 notch and
make sure that parking bralte warning light comes on. if not,
adjust parking bralte warning light contact switch.
- Install parking brake lever boot. Install road wheel lug bolts.
Tightening torque Road
wheel to hub 120 i. 10 Nrn (89 i- 7 ft-lb)
Parking brake shoes, removing and
installing
- Raise rear of car and remove road 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
jaclc stands under suspension
parts.
- Without disconnecting brake fluid hose, remove rear bralte
calipers from trailing arms. Remove rear brake rotors as de-
scribed earlier.
CAUTION-
Do not let the brake caliper assembly hang from the brake
hose. Support caliper from chassis with strong wire.
4 Unhook return sprlngs (arrows) from brake shoes

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340-24
Brakes
4 Remove brake shoe retaining pins using BMW special tool
34 4 000 or equivalent.
Rotate retainer
114 turn to release.
Spread shoes apart and lift out.
4 Note position of bralte shoe adjuster (arrow).
Right side is illustrated. Left is mirror image of this.
- Apply thin coat of grease to sliding parts and pins before re-
assembly.
- Installation is reverse of removal. Be sure to adjust parlting
bralte cables as described earlier.
Tightening torque
Road wheel to
hub 120 i lo Nm (89 i 7 ft-lb)
Parking brake cable, replacing
The parking brake is actuated by two separate Bowden ca-
bles. Each cable can be replaced separately.
- Working inside car, gain access to base of parking brake -
handle by removing center console storage tray and center
armrest, as necessary.
4 Use BMW special tool 34 1 030 or equivalent deep 10 mm
socket to remove parlting brake cable
loclc nuts (A) at base of
parking brake handle.
- Raise rear of car.
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 jaclc stands under suspension
Darfs.

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1 Brakes
ABS COMPONENT REPLACEMENT
CA UTIOW-
If the tires on the car are of different makes, the ABS/trac-
tion controlsystem may overreact. Only fit tires of the same
make and treadpattern.
In adverse conditions, such as trying to rock the car out
of deep snow or other soft surface, or when snow
chains are fitted, it is advisable to switch off traction
control and allow
tlie car driveline to operate conven-
tionally.
All E39 vehicles are equipped with
Antilock Braking System
(ABS). Early production models featured ABS with Automatic
Stability Control (ABS
I ASC). Later models came equipped
with ABS and Dynamic Stability Control (ABS
/ DSC). This
manual will refer to these systems as ABS. ASC or DSC will
be specified when necessary.
For ABS system and component descriptions, see
300 Sus-
pension, Steering and Brakes-General.
Wheel speed sensor, replacing
- Raise applicable end of car.
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
< Front sensor: Unscrew mounting bolts (arrows) at steering
knuckle.
4 Rear sensor: Unscrew mounting bolt (arrows) in rear wheel
bearing carrier.
NOTE-
ABS wheelspeed sensor application may vary depending on
traction control system installed.

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1 Brakes
- Remove precharge pump mounting bracket fasteners and re-
move pump.
- Installation is reverse of removal, noting the following:
Be sure to replace rubber pump mounts if damaged
01
worn.
Bleed brakes as described earlier.
Tightening torque Brake line
to precharge pump 18 Nrn (13 ft-lb)
DSC pressure sensor (1 999 - 2002 models)
On 1999 and later DSC systems, the DSC pressure sensor is
screwed into the DSC hydraulic unit (right rear of engine com-
partment).
WARNING-
* €39 cars require special BMW service equipment to prop-
erly bleed the brakes. Removal of the
DSCpressure sensor
is not recommended unless this equipment is available. For
safety reasons, the brake system on cars with ABS must be
bled using the procedures described in this repair group.
Switch off ignition and remove
key to male sure brake
system cannot be activated.
- Disconnect electrical harness connector at switch.
- Use BMW special tool 34 5 160 to remove and install sensor.
Inspect threads and sealing surfaces for damage.
* Work quicltly to avoid excessive brake fluid leakage.
Tightening torque
Pressure sensor
to hydraulic 19 Nrn (14ft-lb)
unit
- Reconnect harness connector
- Bleed front brakes as described earlier.
- Press on brakes and check for leaks at sensor.
- Turn on ignition and firmly depress brake pedal. Check that
DSC warning light does not come on.

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340-31
Brakes
ABS 1 traction electronic control module
(1 997 -1 998 models)
4 The traction control electronic control module in 1997- 1998
models is located to the left of the glove compartment.
NOTE-
In both ASC and early DSC systems this location is used for
the electronic control unit.
- Before removing the traction control electronic module, read
any fault codes in memory.
ABS I DSC control module
(1 999 - 2002 models)
The DSC electronic control unit in 1999 and later models
(from 911998) is bolted to the DSC hydraulic unit in the right
rear of the engine compartment.
- Before removing the traction control electronic module, read
any fault codes in memory.
- Install electronic control unit using new screws.
Tightening torque
DSC electronic control unit to 2.9 Nrn (26 in-lb)
hydraulic
unit (use new screws)
- Code newly installed module using either DIS or MoDiC.
- Adjust steering angle sensor using menu item Service func-
tion in
DIS or MoDiC.
ABS I traction control hydraulic unit,
removing and installing
WARNING -
E39 cars require special BMWsewice equipment to properly
bleed the brakes. Removal of the hydraulic unit is not recom-
mended unless this equipment is available. For safety rea-
sons, the
brake system on cars with ABS must be bled using
the procedures described in this repair group.
NOTE-
Before starting this procedure, read control module mem-
ory and print
out diagnostic record.
DSC system: Adjust steering angle sensor using
either
DISplus, GTI, or MoDiC. After completing work, function
test control module.