1991 BMW 3 SERIES change wheel

5 Ignition system- general
information and precautions
The ignition system includes the ignition
switch, the battery, the distributor, the primary
(low-voltage/low-tension or LT) and
secondary (high-voltage/high-tension or HT)
wiring circuits, the spark plugs and the spark
plug leads. Models fitted with a carburettor or
L-Jetronic fuel injection are equipped with a
Transistorised Coil Ignition (TCI) system.
Models fitted with the Motronic fuel injection
system have the ignition system incorporated
within the Motronic system (Digital Motor
Electronics or DME).
Transistorised Coil Ignition (TCI)
system
This system is has four major components;
the impulse generator, the ignition control
unit, the coil, and the spark plugs. The
impulse generator provides a timing signal for
the ignition system. Equivalent to cam-
actuated breaker points in a standard
distributor, the impulse generator creates an
A/C voltage signal every time the trigger
wheel tabs pass the impulse generator tabs.
When the ignition control unit (capacitive
discharge unit) receives the voltage signal, it
triggers a spark discharge from the coil by
interrupting the primary coil circuit. The
ignition dwell (coil charging time) is adjusted
by the ignition control unit for the most
intense spark. Note: The air gap (distance
between the impulse generator and trigger
wheel tabs) can be adjusted (see Section 11).
Ignition timing is mechanically adjusted
(see Section 7). A centrifugal advance unit
that consists of spring-loaded rotating
weights advances ignition timing as engine
speed increases. The vacuum advance
adjusts ignition timing to compensate for
changes in engine load.
Motronic ignition system
This system, also known as Digital Motor
Electronics (DME), incorporates all ignition
and fuel injection functions into one central
control unit or ECU (computer). The ignition
timing is based on inputs the ECU receives for
engine load, engine speed, coolant
temperature and intake air temperature. The
only function the distributor performs is the
distribution of the high voltage signal to the
individual spark plugs. The distributor is
attached directly to the cylinder head. There is
no mechanical spark advance system used on
these systems.
Ignition timing is electronically-controlled,
and is not adjustable on Motronic systems.
During starting, a crankshaft position sensor
(reference sensor) relays the crankshaft
position to the ECU, and an initial baseline
ignition point is determined. Once the engineis running, the ignition timing is continually
changing, based on the various input signals
to the ECU. Engine speed is signalled by a
speed sensor. Early Motronic systems have
the position reference sensor and the speed
sensor mounted on the bellhousing over the
flywheel on the left-hand side. Later Motronic
systems have a single sensor (pulse sensor)
mounted over the crankshaft pulley. This
sensor functions as a speed sensor as well as
a position reference sensor. Refer to Sec-
tion 12 for checking and renewing the ignition
sensors. Note: Some models are equipped
with a TDC sensor mounted on the front of the
engine. This sensor is strictly for the BMW
service test unit, and it is not part of the
Motronic ignition system.
Precautions
Certain precautions must be observed
when working on a transistorised ignition
system.
a) Do not disconnect the battery cables
when the engine is running
b) Make sure the ignition control unit (TCI
ignition system) is always well earthed
(see Section 10).
c) Keep water away from the distributor and
HT leads.
d) If a tachometer is to be connected to the
engine, always connect the tachometer
positive (+) lead to the ignition coil
negative terminal (-) and never to the
distributor.
e) Do not allow the coil terminals to be
earthed, as the impulse generator or coil
could be damaged.
f) Do not leave the ignition switch on for
more than ten minutes with the engine
off, or if the engine will not start.
6 Ignition system- check
2
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is
performed involving ignition components.
This not only includes the impulse
generator (electronic ignition), coil,
distributor and spark plug HT leads, but
related components such as spark plug
connectors, tachometer and other test
equipment.
1If the engine turns over but will not start,
disconnect the spark plug HT lead from any
spark plug, and attach it to a calibrated spark
tester (available at most car accessory
shops).
Note:There are two different types of spark
testers. Be sure to specify electronic
(breakerless) ignition. Connect the clip on thetester to an earth point such as a metal
bracket (see illustration).
2If you are unable to obtain a calibrated
spark tester, remove the spark plug HT lead
from one of the spark plugs. Using an
insulated tool, hold the lead about a quarter-
inch from the engine block - make sure the
gap is not more than a quarter-inch, or
damage may be caused to the electronic
components.
3Crank the engine, and observe the tip of the
tester or spark plug HT lead to see if a spark
occurs. If bright-blue, well-defined sparks
occur, sufficient voltage is reaching the plugs
to fire the engine. However, the plugs
themselves may be fouled, so remove and
check them as described in Chapter 1.
4If there’s no spark, check another HT lead
in the same manner. A few sparks followed by
no spark is the same condition as no spark at
all.
5If no spark occurs, remove the distributor
cap, and check the cap and rotor as
described in Chapter 1. If moisture is present,
use a water-dispersant aerosol (or something
similar) to dry out the cap and rotor, then refit
the cap and repeat the spark test.
6If there’s still no spark, disconnect the coil
HT lead from the distributor cap, and
test this lead as described for the spark plug
leads.
7If no spark occurs, check the primary wire
connections at the coil to make sure they’re
clean and tight. Make any necessary repairs,
then repeat the check.
8If sparks do occur from the coil HT lead, the
distributor cap, rotor, plug HT lead(s) or spark
plug(s) may be defective. If there’s still no
spark, the coil-to-cap HT lead may be
defective. If a substitute lead doesn’t make
any difference, check the ignition coil (see
Section 9). Note:Refer to Sections 10 and 11
for more test procedures on the distributors
fitted with the TCI ignition system.
Engine electrical systems 5•3
6.1 To use a spark tester, simply
disconnect a spark plug HT lead, clip the
tester to a convenient earth (like a valve
cover bolt or nut) and operate the starter –
if there is enough power to fire the plug,
sparks will be visible between the
electrode tip and the tester body
5

and down - you should feel a slight drag on
the feeler gauge as it is moved if the gap is
correct. The gap must be as given in this
Chapter’s Specifications.
3To adjust the gap, it is necessary to remove
the impulse generator and the baseplate
assembly from the distributor (see illus-
tration 10.1).
4Follow paragraphs 17 to 24 in Section 10
and loosen the screws that retain the impulse
generator to the baseplate assembly.
5Carefully insert the feeler gauge and tighten
the screws.
6Refit the assembly back into the distributor
and recheck the adjustment.12 Ignition sensors (Motronic
system)- check and renewal
2
Note:Some models are equipped with a TDC
sensor mounted on the front of the engine.
This sensor is strictly for the BMW service test
unit, and is not part of the Motronic ignition
system.
Speed and position sensors
Check
1Locate the two electrical connectors for the
sensors (see illustrations). The grey
connector is for the position sensor, and the
white connector is for the speed sensor.
2Using an ohmmeter, check the resistance
between terminal 1 (yellow wire) and terminal
2 (black wire) on the sensor side of each
connector. The resistance should be 860 to
1,060 ohms.
3Also check the resistance between terminal
3 and either terminal 1 or terminal 2. The
resistance should be approximately 100 000
ohms.
4If the reading(s) are incorrect, renew the
sensor(s).
Renewal
5Remove the sensor mounting screw(s),using an Allen key where necessary, and pull
the sensor(s) from the sockets. Disconnect
the wiring from one sensor at a time - be sure
the connectors are not interchanged when
fitting new sensors. The bellhousing is marked
with a B for the position sensor (grey
connector) and D for the speed sensor (black
connector) (see illustration). Note: It is a
good idea to check the condition of the raised
pin on the flywheel while the sensors are out
of the sockets. Turn the engine by hand as
necessary to bring the pin into view.
6Tighten the sensor mounting screw(s)
securely, but be careful not to overtighten.
Pulse sensor (later models)
Check
7Locate the two electrical connectors for the
sensor (see illustrations). Disconnect the
electrical connector from the front.
8Using an ohmmeter, check resistance
between terminal 1 (yellow wire) and terminal
2 (black wire) on the sensor side of each
connector (see illustration). The resistance
should be 500 to 600 ohms.
9If the reading is incorrect, renew the sensor.
Renewal
10Remove the pulse sensor mounting bolt
using a 5 mm hex spanner (see illustration).
5•8 Engine electrical systems
12.10 The pulse sensor itself (arrowed) is
located on the timing belt cover, to one
side of the pulley (later models)12.8 The resistance of the pulse sensor
should be 500 to 600 ohms (later models)12.7b On later 5-Series models, the pulse
sensor connector (arrowed) is located next
to the valve cover
12.7a On later 3-Series models, the pulse
sensor connector (arrowed) is located next
to the 20-pin diagnostic connector
12.5 Location of the position sensor (B) and
speed sensor (D) on the bellhousing on all
Motronic systems – do not interchange the
sensors, or the engine will not start12.1b Location of the position sensor
(grey connector) (A) and the speed sensor
(black connector) (B) on Motronic systems
(later models)12.1a Location of the position sensor (grey
connector) (A) and the speed sensor (black
connector) (B) on Motronic systems (early
models)

slightly by hand. Release the throttle slowly
until it reaches 0.2 to 0.6 mm from the throttle
stop. There should be continuity.
29Check the resistance between terminals 3
and 18 as the throttle is opened. There should
be continuity when the throttle switch is within
8 to 12 degrees of fully-open. If the readings
are incorrect, adjust the TPS.
30If all the resistance readings are correct
and the TPS is properly adjusted, check for
power (5 volts) at the sensor, and if necessary
trace any wiring circuit problems between the
sensor and ECU (see Chapter 12).
Adjustment
31If the adjustment is not as specified
(paragraphs 28 to 30), loosen the screws on
the TPS, and rotate the sensor into the correct
adjustment. Follow the procedure for
checking the TPS given above, and tighten
the screws when the setting is correct.
32Recheck the TPS once more; if the
readings are correct, reconnect the TPS
harness connector.
Early 535i models with automatic
transmission
Check
33First test the continuity of the TPS. Follow
paragraphs 28 to 30 and check for continuity.
34Next, test the idle position switch (see
illustration). Unplug the electrical connector
in the idle position switch harness, andconnect an ohmmeter to terminals 1 and 2.
There should be continuity. Open the throttle
slightly, and measure the resistance. There
should now be no continuity.
35Check for the correct voltage signals from
the TPS, with the throttle closed and the
ignition on. Probe the back of the TPS
connector with a voltmeter, and check for
voltage at terminal 3 (black wire) and earth.
There should be 5 volts present. Also, probe
terminal 3 (black wire) and terminal 1 (brown
wire). There should be 5 volts present here
also.
36Check for voltage at terminal 2 (yellow
wire) and terminal 1 (brown wire), and slowly
open the throttle. The voltage should increase
steadily from 0.7 volts (throttle closed) to
4.8 volts (throttle fully-open).
Adjustment
37First measure the stabilised voltage. With
the ignition on and the throttle closed,
measure the voltage between terminal 3
(black wire) and terminal 1 (brown wire). It
should be about 5 volts.
38Next, loosen the sensor mounting screws,
and connect the voltmeter to terminal 2
(yellow wire) and terminal 3 (black wire). With
the throttle fully open, rotate the switch until
there is 0.20 to 0.24 volts less than the
stabilised voltage. Note: You will need a
digital voltmeter to measure these small
changes in voltage.
39Recheck the TPS once more; if the
readings are correct, reconnect the TPS
electrical connector. It is a good idea to lock
the TPS screws with paint or thread-locking
compound.
Airflow meter
General description
40The airflow meter is located on the air
intake duct. The airflow meter measures the
amount of air entering the engine. The ECU
uses this information to control fuel delivery. A
large volume of air indicates acceleration,
while a small volume of air indicates
deceleration or idle. Refer to Chapter 4 for all
the diagnostic checks and renewal
procedures for the airflow meter.
Ignition timing sensors
41Ignition timing is electronically-controlled
on Motronic systems, and is not adjustable.
During starting, a crankshaft position sensor
relays the crankshaft position to the ECU, and
an initial baseline ignition point is determined.
Once the engine is running, the ignition point
is continually changing based on the various
input signals to the ECU. Engine speed is
signalled by a speed sensor. Early Motronic
systems have the reference sensor and the
speed sensor mounted on the bellhousing
over the flywheel. Later Motronic systems
have a single sensor (pulse sensor) mounted
over the crankshaft pulley. This sensor
functions as a speed sensor as well as a
position sensor. Refer to Chapter 5 for more
information. Note: Some models are
equipped with a TDC sensor mounted on the
front of the engine. This sensor is strictly for
the BMW service test unit, and it is not part of
the Motronic ignition system.
5 Positive crankcase
ventilation (PCV) system
1The Positive Crankcase Ventilation (PCV)
system (see illustration)reduces
hydrocarbon emissions by scavenging
crankcase vapours. It does this by circulating
blow-by gases and then re-routing them to
the intake manifold by way of the air cleaner.
2This PCV system is a sealed system. The
crankcase blow-by vapours are routed
directly to the air cleaner or air collector with
crankcase pressure behind them. The vapour
is not purged with fresh air on most models or
6•4 Engine management and emission control systems
5.2 PCV hose being removed from the
valve cover5.1 Diagram of the PCV system on the
M20 engine (others similar)4.34 Idle position switch and TPS on early
535i models with automatic transmission
4.28c . . . then check for continuity
between terminals 3 and 18 as the throttle
is opened

Torque wrench settingsNm
Front disc brake caliper
Caliper guide (mounting) bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 35
Caliper bracket-to-strut housing bolts
3-Series, E30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
5-Series, E34 (“new-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Rear disc brake caliper
Caliper guide (mounting) bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 to 35
Carrier-to-trailing arm bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Brake hose-to-caliper fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 to 17
Master cylinder-to-brake servo nuts
3-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5-Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 to 29
Brake servo mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 24
Hydraulic line-to-hydraulic brake servo threaded
fittings - 5-Series, E28 (“old-shape”) . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Wheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
9•2 Braking system
1 General information
All 3-Series models, and 5-Series E28 (“old-
shape”) models, are equipped with front disc
brakes and either rear drum or rear disc
brakes. 5-Series E34 (“new-shape”) models
have disc brakes front and rear. Front and
rear brakes are self-adjusting on all models.
Some later models are equipped with an Anti-
lock Braking System (ABS); this is described
in Section 2.
Hydraulic system
The hydraulic system consists of two
separate circuits. The master cylinder has
separate reservoirs for the two circuits; in the
event of a leak or failure in one hydraulic
circuit, the other circuit will remain operative.
Brake servo
The vacuum brake servo, utilising engine
manifold vacuum and atmospheric pressure
to provide assistance to the hydraulically
operated brakes, is mounted on the bulkhead
in the engine compartment.
A hydraulic brake servo system is used on
5-Series E28 models. This system uses
hydraulic pressure from the power steering
pump to assist braking.
Handbrake
The handbrake operates the rear brakes,
and is cable-operated via a lever mounted in
the centre console. The handbrake assembly
on rear drum brake models is part of the rear
drum brake assembly, and is self-adjusting.
On rear disc brake models, the handbrake
uses a pair of brake shoes located inside the
centre portion of the rear brake disc, and is
manually-adjusted.
Brake pad wear warning system
The brake pad wear warning system is
linked to a red warning light in the instrumentcluster, which comes on when the brake pads
have worn down to the point at which they
require renewal. DO NOT ignore this reminder.
If you don’t renew the pads shortly after the
brake pad wear warning light comes on, the
brake discs will be damaged.
On some models, the brake pad wear
warning system also includes an early
warning light that comes on only when the
brake pedal is depressed, letting you know in
advance that the pads need to be renewed.
The wear sensor is attached to the brake
pads. The sensor is located at the left front
wheel; on some models, there is another
sensor at the right rear wheel. The wear
sensor is part of a closed circuit. Once the
pads wear down to the point at which they’re
flush with the sensor, the disc grinds away the
side of the sensor facing the disc. Thus, the
wire inside the sensor is broken, and the red
light on the instrument panel comes on.
Always check the sensor(s) when renewing
the pads. If you change the pads before the
warning light comes on, the sensor(s) may still
be good; once the light has come on, renew
the sensor.
Service
After completing any operation involving
dismantling of any part of the brake system,
always test drive the vehicle to check for
proper braking performance before resuming
normal driving. When testing the brakes, try to
select a clean, dry, road with no camber (ie as
flat as possible) and with no other traffic.
Conditions other than these can lead to
inaccurate test results.
Test the brakes at various speeds with both
light and heavy pedal pressure. The vehicle
should stop evenly, without pulling to one side
or the other. Avoid locking the brakes,
because this slides the tyres and diminishes
braking efficiency and control of the vehicle.
Tyres, vehicle load and wheel alignment are
factors which also affect braking
performance.
2 Anti-lock Braking system
(ABS)- general information
The Anti-lock Braking System is designed
to maintain vehicle control, directional stability
and optimum deceleration under severe
braking conditions on most road surfaces. It
does so by monitoring the rotational speed of
each wheel and controlling the brake line
pressure to each wheel during braking. This
prevents the wheels from locking up.
The ABS system has three main
components - the wheel speed sensors, the
electronic control unit, and the hydraulic
control unit. The sensors - one at each wheel
since 1985, but at both front wheels and one
at the rear differential on earlier models - send
a variable voltage signal to the control unit,
which monitors these signals, compares them
to its program information, and determines
whether a wheel is about to lock up. When a
wheel is about to lock up, the control unit
signals the hydraulic unit to reduce hydraulic
pressure (or not increase it further) at that
wheel’s brake caliper. Pressure modulation is
handled by electrically-operated solenoid
valves.
If a problem develops within the system, an
“ABS” warning light will glow on the
dashboard. Sometimes, a visual inspection of
the ABS system can help you locate the
problem. Carefully inspect the ABS wiring
harness. Pay particularly close attention to the
harness and connections near each wheel.
Look for signs of chafing and other damage
caused by incorrectly-routed wires. If a wheel
sensor harness is damaged, the sensor
should be renewed (the harness and sensor
are integral).
Warning: DO NOT try to repair an
ABS wiring harness. The ABS
system is sensitive to even the
smallest changes in resistance. Repairing
the harness could alter resistance values

6Be sure to inspect the wear sensor(s) (left
front wheel only, or left front and right rear
wheel). If they’re OK, transfer them from the
old pads to the new ones; if they’re worn by
abrasion, fit new sensors on the new pads.
7To fit the new pads, reverse the removal
procedure. When refitting the caliper, be sure
to tighten the mounting bolts to the torque
listed in this Chapter’s Specifications.
Warning: Check and if necessary
renew the mounting bolts on 3-
Series models whenever they are
removed. If in doubt, use new
bolts.
8After the job is completed, firmly depress
the brake pedal a few times, to bring the pads
into contact with the discs. The pedal shouldbe at normal height above the floor, and firm.
Check the level of the brake fluid, adding
some if necessary. Check carefully for leaks,
and check the operation of the brakes before
returning the vehicle to normal service.
9Avoid heavy braking as far as possible for
the first hundred miles or so until the new
pads have bedded in.
4 Disc brake caliper- removal,
overhaul and refitting
4
Warning: Dust created by the
brake system may contain
asbestos, which is harmful to
your health. Never blow it out
with compressed air, and don’t inhale any
of it. An approved filtering mask should be
worn when working on the brakes. Do not,
under any circumstances, use petroleum-
based solvents to clean brake parts. Use
brake system cleaner only!
Warning: Brake fluid is
poisonous. It is also an effective
paint stripper. Refer to the
warning at the start of Section 16.
Note:If an overhaul is indicated (usually
because of fluid leakage), explore all options
before beginning the job. Overhauled calipers
may be available on an exchange basis, which
makes this job quite easy. If you decide to
overhaul the calipers, make sure that anoverhaul kit is available before proceeding.
Always overhaul the calipers in pairs - never
overhaul just one of them.
Removal
1Loosen the wheel bolts, raise the front or
rear of the vehicle, and place it securely on
axle stands. Remove the wheel.
2If you’re just removing the caliper for
access to other components, it isn’t
necessary to detach the brake line. If you’re
removing the caliper for overhaul, disconnect
the brake line from the caliper, for preference
using a split ring (“brake”) spanner to protect
the fitting. Plug the line, to keep contaminants
out of the brake system and to prevent losing
brake fluid unnecessarily.
3Refer to Section 3 for the front or rear
caliper removal procedure - it’s part of the
brake pad renewal procedure. Note:The rear
caliper is similar in design to the front caliper
on 5-series models.
Overhaul
4On all calipers except the front calipers on
3-Series models, remove the circlip for the
dust seal (see illustration),then remove the
dust boot (see illustration). Before you
remove the piston, place a block of wood
between the piston and caliper to prevent
damage as it is removed.
5To remove the piston from the caliper,
apply compressed air to the brake fluid hose
connection on the caliper body (see
9•4 Braking system
3.5l Hang the caliper out of the way with a
piece of wire
3.5m Remove the outer brake pad - to fit
the new pads, reverse the removal
procedure
3.5k Unclip the inner brake pad from the
piston (5-Series)3.5j Remove the caliper and inner brake
pad (5-Series)
3.5i Depress the piston with a C-clamp
(5-Series)3.5h Prise off the anti-rattle spring
(5-Series)3.5g Remove the plugs for the brake
caliper mounting bolts, then remove the
bolts (5-Series)

26 Wheel alignment-
general information
4
Wheel alignment refers to the adjustments
made to the wheels so they are in proper
angular relationship to the suspension and the
road. Wheels that are out of proper alignment
not only affect vehicle control, but also
increase tyre wear. The front end angles
normally measured are camber, castor and
toe-in (see illustration). Front wheel toe-in is
adjustable on all models; castor is not
adjustable. Camber is only adjustable by
replacing the strut upper mount with a special
eccentric version. Toe-in is adjustable on the
rear wheels, but only by replacing the trailing
arm outer bushings with special eccentric
bushings.
Setting the proper wheel alignment is a very
exacting process, one in which complicated
and expensive equipment is necessary to
perform the job properly. Because of this, you
should have a technician with the proper
equipment perform these tasks. We will,
however, use this space to give you a basic
idea of what is involved with wheel alignment
so you can better understand the process.
Toe-inis the “turning in” of the wheels. The
purpose of a toe specification is to ensureparallel rolling of the wheels. In a vehicle with
zero toe-in, the distance between the front
edges of the wheels will be the same as the
distance between the rear edges of the
wheels. The actual amount of toe-in is
normally very small. On the front end, toe-in is
controlled by the track rod end position on the
track rod. On the rear end, toe-in can only be
adjusted by fitting special eccentric bushings
in the trailing arm outer mounting. Incorrect
toe-in will cause the tyres to wear improperly
by making them scrub against the road
surface.
Camberis the “tilting” of the wheels from
vertical, when viewed from one end of the
vehicle. When the wheels tilt out at the top, the
camber is said to be positive (+). When the
wheels tilt in at the top the camber is negative (-
). The amount of tilt is measured in degrees from
vertical, and this measurement is called the
camber angle. This angle affects the amount of
tyre tread which contacts the road, and
compensates for changes in the suspension
geometry when the vehicle is cornering or
travelling over an undulating surface.
Castoris the “tilting” of the front steering
axis from the vertical. A tilt toward the rear at
the top is positive castor; a tilt toward the
front is negative castor. Castor is not
adjustable on the vehicles covered by this
manual.
Suspension and steering systems 10•17
10
26.1 Wheel alignment details
1 A minus B = C (degrees camber)
2 E minus F = toe-in
(expressed in inches or mm)
3 G = toe-in (expressed in degrees)

REF•19
REF
Buying spare parts & vehicle identification numbers
Buying spare parts
Spare parts are available from many
sources; for example, BMW garages, other
garages and accessory shops, and motor
factors. Our advice regarding spare part
sources is as follows.
Officially-appointed BMW garages- This is
the best source for parts which are peculiar to
your vehicle, and which are not generally
available (eg complete cylinder heads, internal
transmission components, badges, interior
trim etc). It is also the only place at which you
should buy parts if the vehicle is still under
warranty. To be sure of obtaining the correct
parts, it will be necessary to give the storeman
the full Vehicle Identification Number, and if
possible, to take the old parts along for
positive identification. Many parts are
available under a factory exchange scheme -
any parts returned should always be clean. It
obviously makes good sense to go straight to
the specialists on your vehicle for this type of
part, as they are best equipped to supply you.
Other garages and accessory shops- These
are often very good places to buy materials
and components needed for the maintenance
of your vehicle (eg oil filters, spark plugs,
bulbs, drivebelts, oils and greases, touch-up
paint, filler paste, etc). They also sell general
accessories, usually have convenient opening
hours, charge lower prices, and can often be
found not far from home.
Motor factors- Good factors will stock all
the more important components which wearout comparatively quickly (eg exhaust
systems, brake pads, seals and hydraulic
parts, clutch components, bearing shells,
pistons, valves etc). Motor factors will often
provide new or reconditioned components on
a part-exchange basis - this can save a
considerable amount of money.
Vehicle identification
numbers
Modifications are a continuing and
unpublicised process in vehicle manufacture,
quite apart from major model changes. Spare
parts manuals and lists are compiled upon a
numerical basis, the appropriate identification
number or code being essential to correct
identification of the component concerned.When ordering spare parts, always give as
much information as possible. Quote the
vehicle model, year of manufacture, Vehicle
Identification Number and engine numbers, as
appropriate.
The Vehicle Identification Number (VIN)is
located on the right-hand front wheel arch
next to the front suspension strut upper
mounting, on the driver’s door, and on a plate
on top of the facia, just inside the windscreen
(see illustrations).
The engine number is stamped on a
machined face on the left-hand side of the
cylinder block, near the base of the oil level
dipstick tube.
The body numberis located on the seam
between the left-hand front wing and inner
panel.
The VIN (arrowed) is stamped on the
bulkheadThe VIN is also present on the edge of the
driver’s door