1991 BMW 3 SERIES Rear wheel bearing

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•24Glossary of Technical Terms
automatic transmission, a switch that
prevents starting if the vehicle is not in Neutral
or Park.
StrutSee MacPherson strut.
TTappetA cylindrical component which
transmits motion from the cam to the valve
stem, either directly or via a pushrod and
rocker arm. Also called a cam follower.
ThermostatA heat-controlled valve that
regulates the flow of coolant between the
cylinder block and the radiator, so maintaining
optimum engine operating temperature. A
thermostat is also used in some air cleaners in
which the temperature is regulated.
Thrust bearingThe bearing in the clutch
assembly that is moved in to the release levers
by clutch pedal action to disengage the
clutch. Also referred to as a release bearing.
Timing beltA toothed belt which drives the
camshaft. Serious engine damage may result
if it breaks in service.
Timing chainA chain which drives the
camshaft.
Toe-inThe amount the front wheels are
closer together at the front than at the rear. On
rear wheel drive vehicles, a slight amount of
toe-in is usually specified to keep the front
wheels running parallel on the road by
offsetting other forces that tend to spread the
wheels apart.
Toe-outThe amount the front wheels are
closer together at the rear than at the front. Onfront wheel drive vehicles, a slight amount of
toe-out is usually specified.
ToolsFor full information on choosing and
using tools, refer to the Haynes Automotive
Tools Manual.
TracerA stripe of a second colour applied to
a wire insulator to distinguish that wire from
another one with the same colour insulator.
Tune-upA process of accurate and careful
adjustments and parts replacement to obtain
the best possible engine performance.
TurbochargerA centrifugal device, driven by
exhaust gases, that pressurises the intake air.
Normally used to increase the power output
from a given engine displacement, but can
also be used primarily to reduce exhaust
emissions (as on VW’s “Umwelt” Diesel
engine).
UUniversal joint or U-jointA double-pivoted
connection for transmitting power from a
driving to a driven shaft through an angle. A U-
joint consists of two Y-shaped yokes and a
cross-shaped member called the spider.
VValveA device through which the flow of
liquid, gas, vacuum, or loose material in bulk
may be started, stopped, or regulated by a
movable part that opens, shuts, or partiallyobstructs one or more ports or passageways.
A valve is also the movable part of such a
device.
Valve clearanceThe clearance between the
valve tip (the end of the valve stem) and the
rocker arm or tappet. The valve clearance is
measured when the valve is closed.
Vernier caliperA precision measuring
instrument that measures inside and outside
dimensions. Not quite as accurate as a
micrometer, but more convenient.
ViscosityThe thickness of a liquid or its
resistance to flow.
VoltA unit for expressing electrical “pressure”
in a circuit. One volt that will produce a current
of one ampere through a resistance of one
ohm.
WWeldingVarious processes used to join metal
items by heating the areas to be joined to a
molten state and fusing them together. For
more information refer to the Haynes
Automotive Welding Manual.
Wiring diagramA drawing portraying the
components and wires in a vehicle’s electrical
system, using standardised symbols. For
more information refer to the Haynes
Automotive Electrical and Electronic Systems
Manual.

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