1991 BMW 5 SERIES brake switch

12Refitting is a reversal of removal. When
fitting the motor, if necessary plug in the
connector and run the motor briefly until it is
in the “neutral” (wiper parked) position.
17 Heated rear window-
check and repair
2
1The heated rear window consists of a
number of horizontal elements on the glass
surface.
2Small breaks in the element can be repaired
without removing the rear window.
Check
3Switch on the ignition and the heated rear
window.
4Place the positive lead of a voltmeter to the
heater element nearest to the incoming power
source.
5Wrap a piece of aluminium foil around the
negative lead of the voltmeter on the positive
side of the suspected broken element, and
slide it slowly towards the negative side.
Watch the voltmeter needle - when it moves
from zero, you have located the break.
Repair
6Repair the break in the line using a repair kit
recommended specifically for this purpose,
such as BMW repair kit No. 81 22 9 (or
equivalent). Included in this kit is plastic
conductive epoxy. The following paragraphs
give general instructions for this type of repair;
follow the instructions supplied with the repair
kit if they are different.
7Prior to repairing a break, switch off the
circuit and allow it to cool down for a few
minutes.
8Lightly buff the element area with fine steel
wool, then clean it thoroughly.
9Use masking tape to mask off the area of
repair, leaving a slit to which the epoxy can be
applied.
10Mix the epoxy thoroughly, according to
the instructions on the package.
11Apply the epoxy material to the slit in the
masking tape, overlapping the undamaged
area about 20 mm on each end.12Allow the repair to cure for 24 hours
before removing the tape and using the
heated rear window.
18 Supplemental Restraint
System (SRS)- general
information
Later models are equipped with a
Supplemental Restraint System (SRS),
incorporating an airbag. This system is
designed to protect the driver from serious
injury in the event of a head-on or frontal
collision. It consists of an airbag module in the
centre of the steering wheel, two crash
sensors mounted on the front inner wing
panels, and a crash safety switch located
inside the passenger compartment.
The airbag module contains a housing
incorporating the airbag and the inflator units.
The inflator assembly is mounted on the back
of the housing over a hole through which gas
is expelled, inflating the bag almost instanta-
neously when an electrical signal is sent from
the system. This signal is carried by a wire
which is specially wound with several turns,
so the signal will be transmitted regardless of
the steering wheel position.
The SRS system has three sensors: two at
the front, mounted on the inner wing panels
(see illustration), and a safety switch located
inside the passenger compartment. The crash
sensors are basically pressure-sensitive
switches, which complete an electrical circuit
during an impact of sufficient force. The
electrical signal from the crash sensors is sent
to a third sensor, which then completes the
circuit and inflates the airbag.
The module containing the safety switch
monitors the system operation. It checks the
system every time the vehicle is started,
causing the AIRBAG warning light to come on,
then go out if the system is operating
correctly. If there is a fault in the system, the
light will stay on. If the AIRBAG warning light
does stay on, or if it comes on while driving,
take the vehicle to your dealer immediately.
19 Cruise control system-
description and check
1
The cruise control system maintains vehicle
speed using a vacuum-actuated servo motor
located in the engine compartment, which is
connected to the throttle linkage by a cable.
The system consists of the servo motor,
clutch switch, brake switch, control switches,
a relay, and associated vacuum hoses.
Because of the complexity of the cruise
control system, repair should be left to a
dealer service department. However, it is
possible for the home mechanic to make
simple checks of the wiring and vacuum
connections for minor faults which can be
easily repaired. These include:
a) Inspect the cruise control actuating switches
for broken wires and loose connections.
b) Check the cruise control fuse.
c) The cruise control system is operated by
vacuum, so it’s critical that all vacuum
switches, hoses and connections are
secure. Check the hoses in the engine
compartment for loose connections,
cracks, or obvious vacuum leaks.
20 Central locking system-
description and check
2
The central door locking system operates
the door lock actuators mounted in each
door. The system consists of the switches,
actuators and associated wiring. Diagnosis is
limited to simple checks of the wiring
connections and actuators for minor faults
which can be easily repaired. These include:
a) Check the system fuse and/or circuit
breaker (where applicable).
b) Check the switch wires for damage and
loose connections. Check the switches
for continuity.
c) Remove the door trim panel(s), and check
the actuator wiring connections to see if
they’re loose or damaged. Inspect the
actuator rods to make sure they aren’t
12•8 Body electrical systems
18.3 The SRS system crash sensors
(arrowed) are located in the engine
compartment - check the wiring regularly
for damage16.11b Tailgate wiper motor (5-Series)16.11c Wiper blade and pivot mechanism
on the rear window (5-Series)

REF•2MOT Test Checks
Seat belts and seats
Note: The following checks are applicable to
all seat belts, front and rear.
MExamine the webbing of all the belts
(including rear belts if fitted) for cuts, serious
fraying or deterioration. Fasten and unfasten
each belt to check the buckles. If applicable,
check the retracting mechanism. Check the
security of all seat belt mountings accessible
from inside the vehicle.
MThe front seats themselves must be
securely attached and the backrests must
lock in the upright position.
Doors
MBoth front doors must be able to be opened
and closed from outside and inside, and must
latch securely when closed.
Vehicle identification
MNumber plates must be in good condition,
secure and legible, with letters and numbers
correctly spaced – spacing at (A) should be
twice that at (B).
MThe VIN plate and/or homologation plate
must be legible.
Electrical equipment
MSwitch on the ignition and check the
operation of the horn.
MCheck the windscreen washers and wipers,
examining the wiper blades; renew damaged
or perished blades. Also check the operation
of the stop-lights.
MCheck the operation of the sidelights and
number plate lights. The lenses and reflectors
must be secure, clean and undamaged.
MCheck the operation and alignment of the
headlights. The headlight reflectors must not
be tarnished and the lenses must be
undamaged.
MSwitch on the ignition and check the
operation of the direction indicators (including
the instrument panel tell-tale) and the hazard
warning lights. Operation of the sidelights and
stop-lights must not affect the indicators - if it
does, the cause is usually a bad earth at the
rear light cluster.
MCheck the operation of the rear foglight(s),
including the warning light on the instrument
panel or in the switch.
Footbrake
MExamine the master cylinder, brake pipes
and servo unit for leaks, loose mountings,
corrosion or other damage.
MThe fluid reservoir must be secure and the
fluid level must be between the upper (A) and
lower (B) markings.MInspect both front brake flexible hoses for
cracks or deterioration of the rubber. Turn the
steering from lock to lock, and ensure that the
hoses do not contact the wheel, tyre, or any
part of the steering or suspension mechanism.
With the brake pedal firmly depressed, check
the hoses for bulges or leaks under pressure.
Steering and suspension
MHave your assistant turn the steering wheel
from side to side slightly, up to the point where
the steering gear just begins to transmit this
movement to the roadwheels. Check for
excessive free play between the steering
wheel and the steering gear, indicating wear or
insecurity of the steering column joints, the
column-to-steering gear coupling, or the
steering gear itself.
MHave your assistant turn the steering wheel
more vigorously in each direction, so that the
roadwheels just begin to turn. As this is done,
examine all the steering joints, linkages,
fittings and attachments. Renew any
component that shows signs of wear or
damage. On vehicles with power steering,
check the security and condition of the
steering pump, drivebelt and hoses.
MCheck that the vehicle is standing level,
and at approximately the correct ride height.
Shock absorbers
MDepress each corner of the vehicle in turn,
then release it. The vehicle should rise and
then settle in its normal position. If the vehicle
continues to rise and fall, the shock absorber
is defective. A shock absorber which has
seized will also cause the vehicle to fail.
2Checks carried out
WITH THE VEHICLE ON THE
GROUND

REF•9
REF
Fault Finding
Engine
m mEngine will not rotate when attempting to start
m mEngine rotates, but will not start
m mEngine hard to start when cold
m mEngine hard to start when hot
m mStarter motor noisy or excessively-rough in engagement
m mEngine starts, but stops immediately
m mOil puddle under engine
m mEngine idles erratically
m mEngine misses at idle speed
m mEngine misses throughout driving speed range
m mEngine misfires on acceleration
m mEngine surges while holding accelerator steady
m mEngine stalls
m mEngine lacks power
m mEngine backfires
m mPinking or knocking engine sounds when accelerating
or driving uphill
m mEngine runs with oil pressure light on
m mEngine runs-on after switching off
Engine electrical system
m
mBattery will not hold charge
m mIgnition (no-charge) warning light fails to go out
m mIgnition (no-charge) warning light fails to come on
when key is turned
Fuel system
m mExcessive fuel consumption
m mFuel leakage and/or fuel odour
Cooling system
m
mOverheating
m mOvercooling
m mExternal coolant leakage
m mInternal coolant leakage
m mCoolant loss
m mPoor coolant circulation
Clutch
m
mPedal travels to floor - no pressure or very little resistance
m mFluid in area of master cylinder dust cover and on pedal
m mFluid on slave cylinder
m mPedal feels “spongy” when depressed
m mUnable to select gears
m mClutch slips (engine speed increases with no increase in
vehicle speed)
m mGrabbing (chattering) as clutch is engaged
m mNoise in clutch area
m mClutch pedal stays on floor
m mHigh pedal effort
Manual transmission
m
mVibration
m mNoisy in neutral with engine running
m mNoisy in one particular gear
m mNoisy in all gears
m mSlips out of gear
m mLeaks lubricant
Automatic transmission
m
mFluid leakage
m mTransmission fluid brown, or has a burned smell
m mGeneral shift mechanism problems
m mTransmission will not kickdown with accelerator pedal
pressed to the floor
m mEngine will start in gears other than Park or Neutral
m mTransmission slips, shifts roughly, is noisy, or has no drive
in forward or reverse gears
Brakes
m mVehicle pulls to one side during braking
m mNoise (high-pitched squeal) when the brakes are applied
m mBrake vibration (pedal pulsates)
m mExcessive pedal effort required to stop vehicle
m mExcessive brake pedal travel
m mDragging brakes
m mGrabbing or uneven braking action
m mBrake pedal feels “spongy” when depressed
m mBrake pedal travels to the floor with little resistance
m mHandbrake does not hold
Suspension and steering
m
mVehicle pulls to one side
m mAbnormal or excessive tyre wear
m mWheel makes a “thumping” noise
m mShimmy, shake or vibration
m mHigh steering effort
m mPoor steering self-centring
m mAbnormal noise at the front end
m mWandering or poor steering stability
m mErratic steering when braking
m mExcessive pitching and/or rolling around corners or
during braking
m mSuspension bottoms
m mUnevenly-worn tyres
m mExcessive tyre wear on outside edge
m mExcessive tyre wear on inside edge
m mTyre tread worn in one place
m mExcessive play or looseness in steering system
m mRattling or clicking noise in steering gear

REF•11
REF
Fault Finding
Engine misses at idle speed
m mSpark plugs worn or incorrectly-gapped (Chapter 1).
m mFaulty spark plug HT leads (Chapter 1).
m mVacuum leaks (Chapter 1).
m mIncorrect ignition timing (Chapter 5).
m mUneven or low compression (Chapter 2).
m mFaulty charcoal canister, where fitted (Chapter 6).
Engine misses throughout driving speed range
m
mFuel filter clogged and/or impurities in the fuel system (Chapter 1).
m mLow fuel output at the injectors, or partially-blocked carburettor
jets (Chapter 4).
m mFaulty or incorrectly-gapped spark plugs (Chapter 1).
m mIncorrect ignition timing (Chapter 5).
m mCracked distributor cap, disconnected distributor HT leads, or
damaged distributor components (Chapter 1).
m mFaulty spark plug HT leads (Chapter 1).
m mFaulty emission system components (Chapter 6).
m mLow or uneven cylinder compression pressures (Chapter 2).
m mWeak or faulty ignition system (Chapter 5).
m mVacuum leak in fuel injection system, intake manifold or vacuum
hoses (Chapter 4).
Engine misfires on acceleration
m mSpark plugs fouled (Chapter 1).
m mFuel injection system or carburettor malfunctioning (Chapter 4).
m mFuel filter clogged (Chapters 1 and 4).
m mIncorrect ignition timing (Chapter 5).
m mIntake manifold air leak (Chapter 4).
Engine surges while holding accelerator steady
m
mIntake air leak (Chapter 4).
m mFuel pump faulty (Chapter 4).
m mLoose fuel injector harness connections (Chapters 4 and 6).
m mDefective ECU (Chapter 5).
Engine lacks power
m
mIncorrect ignition timing (Chapter 5).
m mExcessive play in distributor shaft (Chapter 5).
m mWorn rotor, distributor cap or HT leads (Chapters 1 and 5).
m mFaulty or incorrectly-gapped spark plugs (Chapter 1).
m mFuel injection system or carburettor malfunctioning (Chapter 4).
m mFaulty coil (Chapter 5).
m mBrakes binding (Chapter 1).
m mAutomatic transmission fluid level incorrect (Chapter 1).
m mClutch slipping (Chapter 8).
m mFuel filter clogged and/or impurities in the fuel system (Chapter 1).
m mEmission control system not functioning properly (Chapter 6).
m mLow or uneven cylinder compression pressures (Chapter 2).
Engine stalls
m
mIdle speed incorrect (Chapter 1).
m mFuel filter clogged and/or water and impurities in the fuel system
(Chapter 1).
m mDistributor components damp or damaged (Chapter 5).
m mFaulty emissions system components (Chapter 6).
m mFaulty or incorrectly-gapped spark plugs (Chapter 1).
m mFaulty spark plug HT leads (Chapter 1).
m mVacuum leak in the fuel injection system, intake manifold or
vacuum hoses (Chapter 4).
Engine backfires
m mEmissions system not functioning properly (Chapter 6).
m mIgnition timing incorrect (Chapter 5).
m mFaulty secondary ignition system (cracked spark plug insulator,
faulty plug HT leads, distributor cap and/or rotor) (Chapters 1 and 5).
m mFuel injection system or carburettor malfunctioning (Chapter 4).
m mVacuum leak at fuel injector(s), intake manifold or vacuum hoses
(Chapter 4).
m mValve clearances incorrect (Chapter 1), or valve(s) sticking or
damaged (Chapter 2).
Pinking or knocking engine sounds when
accelerating or driving uphill
m mIncorrect grade of fuel.
m mIgnition timing incorrect (Chapter 5).
m mFuel injection system or carburettor in need of adjustment (Chap-
ter 4).
m mDamaged spark plugs or HT leads, or incorrect type fitted (Chapter 1).
m mWorn or damaged distributor components (Chapter 5).
m mFaulty emission system (Chapter 6).
m mVacuum leak (Chapter 4).
Engine runs with oil pressure light on
Caution: Stop the engine immediately if the oil
pressure light comes on and establish the cause.
Running the engine while the oil pressure is low can
cause severe damage.
m mLow oil level (Chapter 1).
m mIdle speed too low (Chapter 1).
m mShort-circuit in wiring (Chapter 12).
m mFaulty oil pressure sender unit (Chapter 2).
m mWorn engine bearings and/or oil pump (Chapter 2).
Engine runs-on after switching off
m
mIdle speed too high (Chapter 1).
m mExcessive engine operating temperature (Chapter 3).
m mIncorrect fuel octane grade.
m mSpark plugs defective or incorrect grade (Chapter 1).
Engine electrical system
Battery will not hold charge
m
mAlternator drivebelt defective or not adjusted properly (Chapter 1).
m mElectrolyte level low (Chapter 1).
m mBattery terminals loose or corroded (Chapter 1).
m mAlternator not charging properly (Chapter 5).
m mLoose, broken or faulty wiring in the charging circuit (Chapter 5).
m mShort in vehicle wiring (Chapters 5 and 12).
m mInternally-defective battery (Chapters 1 and 5).
m mIgnition (no-charge) warning light bulb blown - on some early
models (Chapter 5)
Ignition (no-charge) warning light fails to go out
m mFaulty alternator or charging circuit (Chapter 5).
m mAlternator drivebelt defective or out of adjustment (Chapter 1).
m mAlternator voltage regulator inoperative (Chapter 5).
Ignition (no-charge) warning light fails to come on
when key is turned
m mWarning light bulb defective (Chapter 12).
m mFault in the printed circuit, wiring or bulbholder (Chapter 12).

REF•18Automotive chemicals and lubricants
A number of automotive chemicals and
lubricants are available for use during vehicle
maintenance and repair. They include a wide
variety of products ranging from cleaning
solvents and degreasers to lubricants and
protective sprays for rubber, plastic and
vinyl.
Cleaners
Carburettor cleaner and choke cleaner
is a strong solvent for gum, varnish and
carbon. Most carburettor cleaners leave a
dry-type lubricant film which will not harden or
gum up. Because of this film, it is not
recommended for use on electrical
components.
Brake system cleaneris used to remove
grease and brake fluid from the brake system,
where clean surfaces are absolutely
necessary. It leaves no residue, and often
eliminates brake squeal caused by
contaminants.
Electrical cleaner removes oxidation,
corrosion and carbon deposits from electrical
contacts, restoring full current flow. It can also
be used to clean spark plugs, carburettor jets,
voltage regulators and other parts where an
oil-free surface is desired.
Moisture dispersantsremove water and
moisture from electrical components such as
alternators, voltage regulators, electrical
connectors and fuse blocks. They are non-
conductive and non-corrosive.
Degreasersare heavy-duty solvents used
to remove grease from the outside of the
engine and from chassis components. They
can be sprayed or brushed on, and are usually
rinsed off with water.
Lubricants
Engine oilis the lubricant formulated for
use in engines. It normally contains a wide
variety of additives to prevent corrosion and
reduce foaming and wear. Engine oil comes in
various weights (viscosity ratings) from 5 to
60. The recommended weight of the oil
depends on the season, temperature and the
demands on the engine. Light oil is used in
cold climates and under light load conditions.
Heavy oil is used in hot climates, and where
high loads are encountered. Multi-viscosity
(multigrade) oils are designed to have
characteristics of both light and heavy oils,
and are available in a number of weights from
5W-20 to 20W-50.
Gear oilis designed to be used in
differentials, manual transmissions and other
areas where high-temperature lubrication is
required.
Chassis and wheel bearing greaseis a
heavy grease used where increased loads and
friction are encountered, such as for wheel
bearings, balljoints, tie-rod ends and universal
joints.High-temperature wheel bearing grease
is designed to withstand the extreme
temperatures encountered by wheel bearings
in disc brake-equipped vehicles. It usually
contains molybdenum disulphide (moly),
which is a dry-type lubricant.
White greaseis a heavy grease for metal-
to-metal applications where water is a
problem. White grease stays soft at both low
and high temperatures, and will not wash off
or dilute in the presence of water.
Assembly lubeis a special extreme-
pressure lubricant, usually containing moly,
used to lubricate high-load parts (such as
main and rod bearings and cam lobes) for
initial start-up of a new engine. The assembly
lube lubricates the parts without being
squeezed out or washed away until the engine
oiling system begins to function.
Silicone lubricants are used to protect
rubber, plastic, vinyl and nylon parts.
Graphite lubricantsare used where oils
cannot be used due to contamination
problems, such as in locks. The dry graphite
will lubricate metal parts while remaining
uncontaminated by dirt, water, oil or acids. It
is electrically conductive, and will not foul
electrical contacts in locks such as the
ignition switch.
Penetrating oilsloosen and lubricate
frozen, rusted and corroded fasteners and
prevent future rusting or freezing.
Heat-sink greaseis a special electrically
non-conductive grease that is used for
mounting electronic ignition modules where it
is essential that heat is transferred away from
the module.
Sealants
RTV sealantis one of the most widely-
used gasket compounds. Made from silicone,
RTV is air-curing; it seals, bonds, waterproofs,
fills surface irregularities, remains flexible,
doesn’t shrink, is relatively easy to remove,
and is used as a supplementary sealer with
almost all low- and medium-temperature
gaskets.
Anaerobic sealantis much like RTV in that
it can be used either to seal gaskets or to form
gaskets by itself. It remains flexible, is solvent-
resistant, and fills surface imperfections. The
difference between an anaerobic sealant and
an RTV-type sealant is in the curing. RTV
cures when exposed to air, while an anaerobic
sealant cures only in the absence of air. This
means that an anaerobic sealant cures only
after the assembly of parts, sealing them
together.
Thread and pipe sealant is used for
sealing hydraulic and pneumatic fittings and
vacuum lines. It is usually made from a Teflon
compound, and comes in a spray, a paint-on
liquid and as a wrap-around tape.
Chemicals
Anti-seize compoundprevents seizing,
chafing, cold welding, rust and corrosion in
fasteners. High-temperature anti-seize,
usually made with copper and graphite
lubricants, is used for exhaust system and
exhaust manifold bolts.
Anaerobic locking compoundsare used
to keep fasteners from vibrating or working
loose, and cure only after installation, in the
absence of air. Medium-strength locking
compound is used for small nuts, bolts and
screws that may be removed later. High-
strength locking compound is for large nuts,
bolts and studs which aren’t removed on a
regular basis.
Oil additivesrange from viscosity index
improvers to chemical treatments that claim
to reduce internal engine friction. It should be
noted that most oil manufacturers caution
against using additives with their oils.
Fuel additivesperform several functions,
depending on their chemical make-up. They
usually contain solvents that help dissolve
gum and varnish that build up on carburettor,
fuel injection and intake parts. They also serve
to break down carbon deposits that form on
the inside surfaces of the combustion
chambers. Some additives contain upper
cylinder lubricants for valves and piston rings,
and others contain chemicals to remove
condensation from the fuel tank.
Miscellaneous
Brake fluidis specially-formulated
hydraulic fluid that can withstand the heat and
pressure encountered in brake systems. It is
poisonous and inflammable. Care must be
taken so this fluid does not come in contact
with painted surfaces or plastics. An opened
container should always be resealed, to
prevent contamination by water or dirt. Brake
fluid absorbs moisture from the air, if left in an
unsealed container.
Weatherstrip adhesiveis used to bond
weatherstripping around doors, windows and
boot lids. It is sometimes used to attach trim
pieces.
Undersealis a petroleum-based, tar-like
substance that is designed to protect metal
surfaces on the underside of the vehicle from
corrosion. It also acts as a sound-deadening
agent by insulating the bottom of the vehicle.
Waxes and polishesare used to help
protect painted and plated surfaces from the
weather. Different types of paint may require
the use of different types of wax and polish.
Some polishes utilise a chemical or abrasive
cleaner to help remove the top layer of
oxidised (dull) paint on older vehicles. In
recent years, many non-wax polishes
containing a wide variety of chemicals such as
polymers and silicones have been introduced.
These non-wax polishes are usually easier to
apply, and last longer than conventional
waxes and polishes.

REF•23
REF
Glossary of Technical Terms
JJump startStarting the engine of a vehicle
with a discharged or weak battery by
attaching jump leads from the weak battery to
a charged or helper battery.
LLoad Sensing Proportioning Valve (LSPV)A
brake hydraulic system control valve that
works like a proportioning valve, but also
takes into consideration the amount of weight
carried by the rear axle.
LocknutA nut used to lock an adjustment
nut, or other threaded component, in place.
For example, a locknut is employed to keep
the adjusting nut on the rocker arm in
position.
LockwasherA form of washer designed to
prevent an attaching nut from working loose.
MMacPherson strutA type of front
suspension system devised by Earle
MacPherson at Ford of England. In its original
form, a simple lateral link with the anti-roll bar
creates the lower control arm. A long strut - an
integral coil spring and shock absorber - is
mounted between the body and the steering
knuckle. Many modern so-called MacPherson
strut systems use a conventional lower A-arm
and don’t rely on the anti-roll bar for location.
MultimeterAn electrical test instrument with
the capability to measure voltage, current and
resistance.
NNOxOxides of Nitrogen. A common toxic
pollutant emitted by petrol and diesel engines
at higher temperatures.
OOhmThe unit of electrical resistance. One
volt applied to a resistance of one ohm will
produce a current of one amp.
OhmmeterAn instrument for measuring
electrical resistance.
O-ringA type of sealing ring made of a
special rubber-like material; in use, the O-ring
is compressed into a groove to provide the
sealing action.Overhead cam (ohc) engineAn engine with
the camshaft(s) located on top of the cylinder
head(s).
Overhead valve (ohv) engineAn engine with
the valves located in the cylinder head, but
with the camshaft located in the engine block.
Oxygen sensorA device installed in the
engine exhaust manifold, which senses the
oxygen content in the exhaust and converts
this information into an electric current. Also
called a Lambda sensor.
PPhillips screwA type of screw head having a
cross instead of a slot for a corresponding
type of screwdriver.
PlastigageA thin strip of plastic thread,
available in different sizes, used for measuring
clearances. For example, a strip of Plastigage
is laid across a bearing journal. The parts are
assembled and dismantled; the width of the
crushed strip indicates the clearance between
journal and bearing.
Propeller shaftThe long hollow tube with
universal joints at both ends that carries
power from the transmission to the differential
on front-engined rear wheel drive vehicles.
Proportioning valveA hydraulic control
valve which limits the amount of pressure to
the rear brakes during panic stops to prevent
wheel lock-up.
RRack-and-pinion steeringA steering system
with a pinion gear on the end of the steering
shaft that mates with a rack (think of a geared
wheel opened up and laid flat). When the
steering wheel is turned, the pinion turns,
moving the rack to the left or right. This
movement is transmitted through the track
rods to the steering arms at the wheels.
RadiatorA liquid-to-air heat transfer device
designed to reduce the temperature of the
coolant in an internal combustion engine
cooling system.
RefrigerantAny substance used as a heat
transfer agent in an air-conditioning system.
R-12 has been the principle refrigerant for
many years; recently, however, manufacturers
have begun using R-134a, a non-CFC
substance that is considered less harmful tothe ozone in the upper atmosphere.
Rocker armA lever arm that rocks on a shaft
or pivots on a stud. In an overhead valve
engine, the rocker arm converts the upward
movement of the pushrod into a downward
movement to open a valve.
RotorIn a distributor, the rotating device
inside the cap that connects the centre
electrode and the outer terminals as it turns,
distributing the high voltage from the coil
secondary winding to the proper spark plug.
Also, that part of an alternator which rotates
inside the stator. Also, the rotating assembly
of a turbocharger, including the compressor
wheel, shaft and turbine wheel.
RunoutThe amount of wobble (in-and-out
movement) of a gear or wheel as it’s rotated.
The amount a shaft rotates “out-of-true.” The
out-of-round condition of a rotating part.
SSealantA liquid or paste used to prevent
leakage at a joint. Sometimes used in
conjunction with a gasket.
Sealed beam lampAn older headlight design
which integrates the reflector, lens and
filaments into a hermetically-sealed one-piece
unit. When a filament burns out or the lens
cracks, the entire unit is simply replaced.
Serpentine drivebeltA single, long, wide
accessory drivebelt that’s used on some
newer vehicles to drive all the accessories,
instead of a series of smaller, shorter belts.
Serpentine drivebelts are usually tensioned by
an automatic tensioner.
ShimThin spacer, commonly used to adjust
the clearance or relative positions between
two parts. For example, shims inserted into or
under bucket tappets control valve
clearances. Clearance is adjusted by
changing the thickness of the shim.
Slide hammerA special puller that screws
into or hooks onto a component such as a
shaft or bearing; a heavy sliding handle on the
shaft bottoms against the end of the shaft to
knock the component free.
SprocketA tooth or projection on the
periphery of a wheel, shaped to engage with a
chain or drivebelt. Commonly used to refer to
the sprocket wheel itself.
Starter inhibitor switchOn vehicles with an
O-ring
Serpentine drivebelt
Plastigage

REF•26Index
E
Earth check - 12•2
Electric fan - 3•4
Electric shock - 0•5
Electric windows - 12•9
Electrical equipment - REF•2
Electrical system fault finding - 12•1
Electronic control system - 4•3, 4•14
Electronic control unit (ECU) - 6•1
Engine fault finding - REF•10
Engine tune-up - 1•7
Engine electrical systems- 5•1et seq
Engine electrical systems fault finding -
REF•11
Engine management and emission control
systems- 6•1et seq
Engine oil - 1•3, 1•7, 1•11
Environmental considerations - REF•8
Evaporative emissions control (EVAP)
system - 1•26, 6•5
Evaporator - 3•10
Exhaust emission checks - REF•4
Exhaust manifold - 2A•6
Exhaust system - 1•21, 4•20, REF•3
F
Fan - 3•4, 3•5
Fault finding- REF•9et seq
Fault finding - automatic transmission -
7B•2, REF•13
Fault finding - braking system - REF•14
Fault finding - clutch - REF•12
Fault finding - cooling system - REF•12
Fault finding - electrical system - 12•1,
REF•11
Fault finding - engine - REF•10
Fault finding - fuel system - 4•21, REF•12
Fault finding - manual transmission -
REF•13
Fault finding - suspension and steering -
REF•15
Filling - 11•3
Final drive - 8•2, 8•10, 8•11
Final drive oil - 1•3, 1•19, 1•26
Fire - 0•5
Flexible coupling - 8•7
Fluid level checks - 1•7
Fluid seals - 7B•5
Flywheel - 2A•18
Fuel and exhaust systems- 1•20, 4•1et
seq,REF•4
Fuel system fault finding - REF•12
Fuel filter - 1•25
Fuel hoses - 1•14
Fuel injection system - 4•3, 4•14
Fuel injection system - fault finding - 4•21
Fuel injectors - 4•18
Fuel level sender unit - 4•5, 4•6
Fuel lines and fittings - 4•7
Fuel pressure - 4•3
Fuel pressure regulator - 4•16
Fuel pump - 4•3, 4•4, 4•5
Fuel tank - 4•7, 4•8
Fume or gas intoxication - 0•5
Fuses - 12•2
G
Gaiters - 1•22, 8•9, 10•13
Gashes in bodywork - 11•2
Gaskets - REF•8
Gear lever - 7A•1
Gearbox - SeeManual transmission
Gearbox oil - 1•3, 1•19, 1•25
General engine overhaul procedures-
2B•1et seq
Glass - 11•4, 11•8
Glossary of technical terms - REF•20
Grille - 11•4
H
Handbrake - 1•23, 9•2, 9•12, REF•1
Handbrake fault - REF•14
Handles - 11•8
Hazard warning flasher - 12•2
HC emissions - REF•4
Headlights - 12•3, 12•5, 12•6
Heated rear window - 12•8
Heater - 3•2, 3•7, 3•8
Hinges - 11•4
HT leads - 1•18
Hubs - 10•8, 10•11, REF•3
Hydraulic servo - 9•11
Hydraulic tappets - 2B•11
Hydrofluoric acid - 0•5
I
Idle air stabiliser valve - 4•18
Idle speed adjustment - 1•15
Ignition coil - 5•5
Ignition control unit - 5•6, 5•7
Ignition sensors - 5•8
Ignition switch - 12•3
Ignition system - 5•3
Ignition timing - 5•4
Ignition timing sensors - 6•4
Impulse generator - 5•6, 5•7
In-car engine repair procedures- 2A•1et
seq
Indicators - 12•2, 12•3
Information sensors - 6•2
Injectors - 4•18
Input shaft - 7A•2
Instrument cluster - 12•4
Instrument panel language display - 0•7
Intake manifold - 2A•4
Intermediate shaft - 2A•12, 2B•14, 2B•19
Introduction to the BMW 3- and 5-Series -
0•4
J
Jacking - 0•8
Joint mating faces - REF•8
Jump starting - 0•9
K
Kickdown cable - 7B•3
L
L-Jetronic fuel injection system - 4•14,
4•19
Language display - 0•7
Latch - 11•8
Leaks - 0•10, 7B•3, REF•12, REF•13
Locknuts, locktabs and washers - REF•8
Locks - 11•4, 11•8
Lubricants - REF•18
M
Main bearings - 2B•17, 2B•19
Manifolds - 2A•4, 2A•6
Manual transmission- 7A•1et seq
Manual transmission fault finding - REF•13
Manual transmission oil - 1•3, 1•19, 1•25
Master cylinder - 8•3, 9•9
Mechanical fan - 3•4, 3•5
Mirrors - 11•8, REF•1
Misfire - REF•11
Mixture - REF•4
MOT test checks- REF•1 et seq
Motronic engine management system -
6•1
Motronic fuel injection system - 4•14, 4•19
Mountings - 2A•19, 7A•3
O
Oil - differential - 1•19, 1•26
Oil - engine - 1•3, 1•7, 1•11
Oil - final drive - 1•3
Oil - manual transmission - 1•3, 1•19, 1•25
Oil filter - 1•11, 1•12
Oil pump - 2A•16
Oil seals - 2A•12, 2A•13, 2A•19, 2B•20,
7A•2, 7B•5, 8•10, 8•12, REF•8
Open-circuit - 12•2
Output shaft - 7A•2, 7B•5
Overcooling - REF•12
Overheating - REF•12
Oxygen sensor - 6•2
P
Pads - 9•2, 9•3
Pedals - 8•3, 9•13
Pinion oil - 8•12
Pinking - REF•11
Piston rings - 2B•18
Pistons - 2B•12, 2B•16, 2B•21
Plastic components - 11•3
Poisonous or irritant substances - 0•5
Position sensors - 5•8
Positive crankcase ventilation (PCV)
system - 6•4
Power steering - 1•14, 10•15, 10•16
Power steering fluid - 1•12
Propeller shaft - 8•2, 8•6, 8•8
Pulse sensor - 5•8
Purge valve - 6•5