1988 OPEL CALIBRA power steering

MOTTest Checks REF•9
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

REF•10MOTTest Checks
Exhaust system
MStart the engine. With your assistant
holding a rag over the tailpipe, check the
entire system for leaks. Repair or renew
leaking sections.
Jack up the front and rear of the vehicle,
and securely support it on axle stands.
Position the stands clear of the suspension
assemblies. Ensure that the wheels are
clear of the ground and that the steering
can be turned from lock to lock.
Steering mechanism
MHave your assistant turn the steering from
lock to lock. Check that the steering turns
smoothly, and that no part of the steering
mechanism, including a wheel or tyre, fouls
any brake hose or pipe or any part of the body
structure.
MExamine the steering rack rubber gaiters
for damage or insecurity of the retaining clips.
If power steering is fitted, check for signs of
damage or leakage of the fluid hoses, pipes or
connections. Also check for excessive
stiffness or binding of the steering, a missing
split pin or locking device, or severe corrosion
of the body structure within 30 cm of any
steering component attachment point.
Front and rear suspension and
wheel bearings
MStarting at the front right-hand side, grasp
the roadwheel at the 3 o’clock and 9 o’clock
positions and shake it vigorously. Check for
free play or insecurity at the wheel bearings,
suspension balljoints, or suspension mount-
ings, pivots and attachments.
MNow grasp the wheel at the 12 o’clock and
6 o’clock positions and repeat the previous
inspection. Spin the wheel, and check for
roughness or tightness of the front wheel
bearing.
MIf excess free play is suspected at a
component pivot point, this can be confirmed
by using a large screwdriver or similar tool and
levering between the mounting and the
component attachment. This will confirm
whether the wear is in the pivot bush, its
retaining bolt, or in the mounting itself (the bolt
holes can often become elongated).
MCarry out all the above checks at the other
front wheel, and then at both rear wheels.
Springs and shock absorbers
MExamine the suspension struts (when
applicable) for serious fluid leakage, corrosion,
or damage to the casing. Also check the
security of the mounting points.
MIf coil springs are fitted, check that the
spring ends locate in their seats, and that the
spring is not corroded, cracked or broken.
MIf leaf springs are fitted, check that all
leaves are intact, that the axle is securely
attached to each spring, and that there is no
deterioration of the spring eye mountings,
bushes, and shackles.MThe same general checks apply to vehicles
fitted with other suspension types, such as
torsion bars, hydraulic displacer units, etc.
Ensure that all mountings and attachments are
secure, that there are no signs of excessive
wear, corrosion or damage, and (on hydraulic
types) that there are no fluid leaks or damaged
pipes.
MInspect the shock absorbers for signs of
serious fluid leakage. Check for wear of the
mounting bushes or attachments, or damage
to the body of the unit.
Driveshafts
(fwd vehicles only)
MRotate each front wheel in turn and inspect
the constant velocity joint gaiters for splits or
damage. Also check that each driveshaft is
straight and undamaged.
Braking system
MIf possible without dismantling, check
brake pad wear and disc condition. Ensure
that the friction lining material has not worn
excessively, (A) and that the discs are not
fractured, pitted, scored or badly worn (B).
MExamine all the rigid brake pipes
underneath the vehicle, and the flexible
hose(s) at the rear. Look for corrosion, chafing
or insecurity of the pipes, and for signs of
bulging under pressure, chafing, splits or
deterioration of the flexible hoses.
MLook for signs of fluid leaks at the brake
calipers or on the brake backplates. Repair or
renew leaking components.
MSlowly spin each wheel, while your
assistant depresses and releases the
footbrake. Ensure that each brake is operating
and does not bind when the pedal is released.
3Checks carried out
WITH THE VEHICLE RAISED
AND THE WHEELS FREE TO
TURN

Engine
m mEngine fails to rotate when attempting to start
m mEngine rotates, but will not start
m mEngine difficult to start when cold
m mEngine difficult to start when hot
m mStarter motor noisy or excessively rough in engagement
m mEngine starts, but stops immediately
m mEngine idles erratically
m mEngine misfires at idle speed
m mEngine misfires throughout the driving speed range
m mEngine hesitates on acceleration
m mEngine stalls
m mEngine lacks power
m mEngine backfires
m mOil pressure warning light illuminated with engine running
m mEngine runs-on after switching off
m mEngine noises
Cooling system
m
mOverheating
m mOvercooling
m mExternal coolant leakage
m mInternal coolant leakage
m mCorrosion
Fuel and exhaust systems
m
mExcessive fuel consumption
m mFuel leakage and/or fuel odour
m mExcessive noise or fumes from exhaust system
Clutch
m
mPedal travels to floor - no pressure or very little resistance
m mClutch fails to disengage (unable to select gears)
m mClutch slips (engine speed increases, with no increase in vehicle
speed)
m mJudder as clutch is engaged
m mNoise when depressing or releasing clutch pedal
Manual transmission
m
mNoisy in neutral with engine running
m mNoisy in one particular gear
m mDifficulty engaging gears
m mJumps out of gear
m mVibration
m mLubricant leaks
Automatic transmission
m
mFluid leakage
m mTransmission fluid brown, or has burned smell
m mGeneral gear selection problems
m mTransmission will not downshift (kickdown) with accelerator fully
depressed
m mEngine will not start in any gear, or starts in gears other than Park
or Neutral
m mTransmission slips, shifts roughly, is noisy, or has no drive in
forward or reverse gears
Driveshafts
m mClicking or knocking noise on turns (at slow speed on full-lock)
m mVibration when accelerating or decelerating
Braking system
m
mVehicle pulls to one side under braking
m mNoise (grinding or high-pitched squeal) when brakes applied
m mExcessive brake pedal travel
m mBrake pedal feels spongy when depressed
m mExcessive brake pedal effort required to stop vehicle
m mJudder felt through brake pedal or steering wheel when braking
m mBrakes binding
m mRear wheels locking under normal braking
Suspension and steering systems
m
mVehicle pulls to one side
m mWheel wobble and vibration
m mExcessive pitching and/or rolling around corners, or during
braking
m mWandering or general instability
m mExcessively stiff steering
m mExcessive play in steering
m mLack of power assistance
m mTyre wear excessive
Electrical system
m
mBattery will not hold a charge for more than a few days
m mIgnition/no-charge warning light remains illuminated with engine
running
m mIgnition/no-charge warning light fails to come on
m mLights inoperative
m mInstrument readings inaccurate or erratic
m mHorn inoperative, or unsatisfactory in operation
m mWindscreen/tailgate wipers inoperative, or unsatisfactory in
operation
m mWindscreen/tailgate washers inoperative, or unsatisfactory in
operation
m mElectric windows inoperative, or unsatisfactory in operation
m mCentral locking system inoperative, or unsatisfactory in operation
The vehicle owner who does his or her own maintenance according to
the recommended service schedules should not have to use this section
of the manual very often. Modern component reliability is such that,
provided those items subject to wear or deterioration are inspected or
renewed at the specified intervals, sudden failure is comparatively rare.
Faults do not usually just happen as a result of sudden failure, but
develop over a period of time. Major mechanical failures in particular are
usually preceded by characteristic symptoms over hundreds or even
thousands of miles. Those components that do occasionally fail without
warning are often small and easily carried in the vehicle.
With any fault-finding, the first step is to decide where to begininvestigations. Sometimes this is obvious, but on other occasions, a
little detective work will be necessary. The owner who makes half a
dozen haphazard adjustments or replacements may be successful in
curing a fault (or its symptoms). However, will be none the wiser if the
fault recurs, and ultimately may have spent more time and money than
was necessary. A calm and logical approach will be found to be more
satisfactory in the long run. Always take into account any warning
signs or abnormalities that may have been noticed in the period
preceding the fault - power loss, high or low gauge readings, unusual
smells, etc. - and remember that failure of components such as fuses
or spark plugs may only be pointers to some underlying fault.
REF•12Fault Finding
Introduction

Note:Before diagnosing suspension or steering faults, be sure that the
trouble is not due to incorrect tyre pressures, mixtures of tyre types, or
binding brakes.
Vehicle pulls to one side
MDefective tyre (Chapter 1).
MExcessive wear in suspension or steering components (Chapters 1
and 10).
MIncorrect front wheel alignment (Chapter 10).
MAccident damage to steering or suspension components
(Chapter 1).
Wheel wobble and vibration
MFront roadwheels out of balance (vibration felt mainly through the
steering wheel), (Chapters 1 and 10).
MRear roadwheels out of balance (vibration felt throughout the
vehicle), (Chapters 1 and 10).
MRoadwheels damaged or distorted (Chapters 1 and 10).
MFaulty or damaged tyre (Chapter 1).
MWorn steering or suspension joints, bushes or components
(Chapters 1 and 10).
MWheel bolts loose (Chapters 1 and 10).
Excessive pitching and/or rolling around corners,
or during braking
MDefective shock absorbers (Chapters 1 and 10).
MBroken or weak spring and/or suspension component (Chapters 1
and 10).
MWorn or damaged anti-roll bar or mountings (Chapter 10).
Wandering or general instability
MIncorrect front wheel alignment (Chapter 10).
MWorn steering or suspension joints, bushes or components
(Chapters 1 and 10).
MRoadwheels out of balance (Chapters 1 and 10).
MFaulty or damaged tyre (Chapter 1).
MWheel bolts loose (Chapters 1 and 10).
MDefective shock absorbers (Chapters 1 and 10).
Excessively stiff steering
MLack of steering gear lubricant (Chapter 10).
MSeized track rod end balljoint or suspension balljoint (Chapters 1
and 10).
MBroken or incorrectly adjusted auxiliary drivebelt - power steering
(Chapter 1).
Fault Finding REF•17
REF
Note:Before assuming that a brake problem exists, make sure that the
tyres are in good condition and correctly inflated, that the front wheel
alignment is correct, and that the vehicle is not loaded with weight in an
unequal manner. Apart from checking the condition of all pipe and
hose connections, any faults occurring on the anti-lock braking system
should be referred to a Peugeot dealer for diagnosis.
Vehicle pulls to one side under braking
MWorn, defective, damaged or contaminated brake pads/shoes on
one side (Chapters 1 and 9).
MSeized or partially seized front brake caliper/wheel cylinder piston
(Chapters 1 and 9).
MA mixture of brake pad/shoe lining materials fitted between sides
(Chapters 1 and 9).
MBrake caliper or backplate mounting bolts loose (Chapter 9).
MWorn or damaged steering or suspension components
(Chapters 1 and 10).
Noise (grinding or high-pitched squeal) when
brakes applied
MBrake pad or shoe friction lining material worn down to metal
backing (Chapters 1 and 9).
MExcessive corrosion of brake disc or drum. This may be apparent
after the vehicle has been standing for some time (Chapters 1 and 9).
MForeign object (stone chipping, etc.) trapped between brake disc
and shield (Chapters 1 and 9).
Excessive brake pedal travel
MInoperative rear brake self-adjust mechanism - drum brakes
(Chapters 1 and 9).
MFaulty master cylinder (Chapter 9).
MAir in hydraulic system (Chapters 1 and 9).
MFaulty vacuum servo unit (Chapter 9).
Brake pedal feels spongy when depressed
MAir in hydraulic system (Chapters 1 and 9).
MDeteriorated flexible rubber brake hoses (Chapters 1 and 9).
MMaster cylinder mounting nuts loose (Chapter 9).
MFaulty master cylinder (Chapter 9).
Excessive brake pedal effort required to stop
vehicle
MFaulty vacuum servo unit (Chapter 9).
MDisconnected, damaged or insecure brake servo vacuum hose
(Chapter 9).
MPrimary or secondary hydraulic circuit failure (Chapter 9).
MSeized brake caliper or wheel cylinder piston(s) (Chapter 9).
MBrake pads or brake shoes incorrectly fitted (Chapters 1 and 9).
MIncorrect grade of brake pads or brake shoes fitted (Chapters 1
and 9).
MBrake pads or brake shoe linings contaminated (Chapters 1 and 9).
Judder felt through brake pedal or steering wheel
when braking
MExcessive run-out or distortion of discs/drums (Chapters 1 and 9).
MBrake pad or brake shoe linings worn (Chapters 1 and 9).
MBrake caliper or brake backplate mounting bolts loose (Chapter 9).
MWear in suspension or steering components or mountings
(Chapters 1 and 10).
Brakes binding
MSeized brake caliper or wheel cylinder piston(s) (Chapter 9).
MIncorrectly adjusted handbrake mechanism (Chapter 9).
MFaulty master cylinder (Chapter 9).
Rear wheels locking under normal braking
MRear brake shoe linings contaminated (Chapters 1 and 9).
MFaulty brake pressure regulator (Chapter 9).
Braking system
Suspension and steering

Note:For problems associated with the starting system, refer to the
faults listed under “Engine” earlier in this Section.
Battery will not hold a charge for more than a few
days
MBattery defective internally (Chapter 5).
MBattery terminal connections loose or corroded (Chapter 1).
MAuxiliary drivebelt worn or incorrectly adjusted (Chapter 1).
MAlternator not charging at correct output (Chapter 5).
MAlternator or voltage regulator faulty (Chapter 5).
MShort-circuit causing continual battery drain (Chapters 5 and 12).
Ignition/no-charge warning light remains
illuminated with engine running
MAuxiliary drivebelt broken, worn, or incorrectly adjusted (Chapter 1).
MAlternator brushes worn, sticking, or dirty (Chapter 5).
MAlternator brush springs weak or broken (Chapter 5).
MInternal fault in alternator or voltage regulator (Chapter 5).
MBroken, disconnected, or loose wiring in charging circuit
(Chapter 5).
Ignition/no-charge warning light fails to come on
MWarning light bulb blown (Chapter 12).
MBroken, disconnected, or loose wiring in warning light circuit
(Chapter 12).
MAlternator faulty (Chapter 5).
Lights inoperative
MBulb blown (Chapter 12).
MCorrosion of bulb or bulbholder contacts (Chapter 12).
MBlown fuse (Chapter 12).
MFaulty relay (Chapter 12).
MBroken, loose, or disconnected wiring (Chapter 12).
MFaulty switch (Chapter 12).
Instrument readings inaccurate or erratic
Instrument readings increase with engine speed
MFaulty voltage regulator (Chapter 12).
Fuel or temperature gauges give no reading
MFaulty gauge sender unit (Chapters 3, 4A and 4B).
MWiring open-circuit (Chapter 12).
MFaulty gauge (Chapter 12).
Fuel or temperature gauges give continuous maximum
reading
MFaulty gauge sender unit (Chapters 3, 4A and 4B).
MWiring short-circuit (Chapter 12).
MFaulty gauge (Chapter 12). MIncorrect front wheel alignment (Chapter 10).
MSteering rack or column bent or damaged (Chapter 10).
Excessive play in steering
MWorn steering column intermediate shaft universal joint
(Chapter 10).
MWorn steering track rod end balljoints (Chapters 1 and 10).
MWorn rack-and-pinion steering gear (Chapter 10).
MWorn steering or suspension joints, bushes or components
(Chapters 1 and 10).
Lack of power assistance
MBroken or incorrectly adjusted auxiliary drivebelt (Chapter 1).
MIncorrect power steering fluid level (Chapter 1).
MRestriction in power steering fluid hoses (Chapter 1).
MFaulty power steering pump (Chapter 10).
MFaulty rack-and-pinion steering gear (Chapter 10).
Tyre wear excessive
Tyres worn on inside or outside edges
MTyres under-inflated (wear on both edges), (Chapter 1).
MIncorrect camber or castor angles (wear on one edge only),
(Chapter 10).
MWorn steering or suspension joints, bushes or components
(Chapters 1 and 10).
MExcessively hard cornering.
MAccident damage.
Tyre treads exhibit feathered edges
MIncorrect toe setting (Chapter 10).
Tyres worn in centre of tread
MTyres over-inflated (Chapter 1).
Tyres worn on inside and outside edges
MTyres under-inflated (Chapter 1).
Tyres worn unevenly
MTyres/wheels out of balance (Chapter 1).
MExcessive wheel or tyre run-out (Chapter 1).
MWorn shock absorbers (Chapters 1 and 10).
MFaulty tyre (Chapter 1).
REF•18Fault Finding
Electrical system
Suspension and steering (continued)

REF•20Glossary of Technical Terms
A
ABS (Anti-lock brake system)A system,
usually electronically controlled, that senses
incipient wheel lockup during braking and
relieves hydraulic pressure at wheels that are
about to skid.
Air bag An inflatable bag hidden in the
steering wheel (driver’s side) or the dash or
glovebox (passenger side). In a head-on
collision, the bags inflate, preventing the
driver and front passenger from being thrown
forward into the steering wheel or windscreen.
Air cleanerA metal or plastic housing,
containing a filter element, which removes
dust and dirt from the air being drawn into the
engine.
Air filter elementThe actual filter in an air
cleaner system, usually manufactured from
pleated paper and requiring renewal at regular
intervals.
Allen keyA hexagonal wrench which fits into
a recessed hexagonal hole.
Alligator clipA long-nosed spring-loaded
metal clip with meshing teeth. Used to make
temporary electrical connections.
AlternatorA component in the electrical
system which converts mechanical energy
from a drivebelt into electrical energy to
charge the battery and to operate the starting
system, ignition system and electrical
accessories.
Ampere (amp)A unit of measurement for the
flow of electric current. One amp is the
amount of current produced by one volt
acting through a resistance of one ohm.
Anaerobic sealerA substance used to
prevent bolts and screws from loosening.
Anaerobic means that it does not require
oxygen for activation. The Loctite brand is
widely used.
AntifreezeA substance (usually ethylene
glycol) mixed with water, and added to a
vehicle’s cooling system, to prevent freezing
of the coolant in winter. Antifreeze also
contains chemicals to inhibit corrosion and
the formation of rust and other deposits thatwould tend to clog the radiator and coolant
passages and reduce cooling efficiency.
Anti-seize compoundA coating that
reduces the risk of seizing on fasteners that
are subjected to high temperatures, such as
exhaust manifold bolts and nuts.
AsbestosA natural fibrous mineral with great
heat resistance, commonly used in the
composition of brake friction materials.
Asbestos is a health hazard and the dust
created by brake systems should never be
inhaled or ingested.
AxleA shaft on which a wheel revolves, or
which revolves with a wheel. Also, a solid
beam that connects the two wheels at one
end of the vehicle. An axle which also
transmits power to the wheels is known as a
live axle.
AxleshaftA single rotating shaft, on either
side of the differential, which delivers power
from the final drive assembly to the drive
wheels. Also called a driveshaft or a halfshaft.
BBall bearingAn anti-friction bearing
consisting of a hardened inner and outer race
with hardened steel balls between two races.BearingThe curved surface on a shaft or in a
bore, or the part assembled into either, that
permits relative motion between them with
minimum wear and friction.
Big-end bearingThe bearing in the end of
the connecting rod that’s attached to the
crankshaft.
Bleed nippleA valve on a brake wheel
cylinder, caliper or other hydraulic component
that is opened to purge the hydraulic system
of air. Also called a bleed screw.
Brake bleedingProcedure for removing air
from lines of a hydraulic brake system.
Brake discThe component of a disc brake
that rotates with the wheels.
Brake drumThe component of a drum brake
that rotates with the wheels.
Brake liningsThe friction material which
contacts the brake disc or drum to retard the
vehicle’s speed. The linings are bonded or
riveted to the brake pads or shoes.
Brake padsThe replaceable friction pads
that pinch the brake disc when the brakes are
applied. Brake pads consist of a friction
material bonded or riveted to a rigid backing
plate.
Brake shoeThe crescent-shaped carrier to
which the brake linings are mounted and
which forces the lining against the rotating
drum during braking.
Braking systemsFor more information on
braking systems, consult the Haynes
Automotive Brake Manual.
Breaker barA long socket wrench handle
providing greater leverage.
BulkheadThe insulated partition between
the engine and the passenger compartment.
CCaliperThe non-rotating part of a disc-brake
assembly that straddles the disc and carries
the brake pads. The caliper also contains the
hydraulic components that cause the pads to
pinch the disc when the brakes are applied. A
caliper is also a measuring tool that can be set
to measure inside or outside dimensions of an
object.
Brake bleeding
Bearing
Axle assembly
Anti-seize compound
Alternator (exploded view)
Air filter

Glossary of Technical Terms REF•21
REF
CamshaftA rotating shaft on which a series
of cam lobes operate the valve mechanisms.
The camshaft may be driven by gears, by
sprockets and chain or by sprockets and a
belt.
CanisterA container in an evaporative
emission control system; contains activated
charcoal granules to trap vapours from the
fuel system.
CarburettorA device which mixes fuel with
air in the proper proportions to provide a
desired power output from a spark ignition
internal combustion engine.
CastellatedResembling the parapets along
the top of a castle wall. For example, a
castellated balljoint stud nut.
CastorIn wheel alignment, the backward or
forward tilt of the steering axis. Castor is
positive when the steering axis is inclined
rearward at the top.Catalytic converterA silencer-like device in
the exhaust system which converts certain
pollutants in the exhaust gases into less
harmful substances.
CirclipA ring-shaped clip used to prevent
endwise movement of cylindrical parts and
shafts. An internal circlip is installed in a
groove in a housing; an external circlip fits into
a groove on the outside of a cylindrical piece
such as a shaft.
ClearanceThe amount of space between
two parts. For example, between a piston and
a cylinder, between a bearing and a journal,
etc.
Coil springA spiral of elastic steel found in
various sizes throughout a vehicle, for
example as a springing medium in the
suspension and in the valve train.
CompressionReduction in volume, and
increase in pressure and temperature, of a
gas, caused by squeezing it into a smaller
space.
Compression ratioThe relationship between
cylinder volume when the piston is at top
dead centre and cylinder volume when the
piston is at bottom dead centre.
Constant velocity (CV) jointA type of
universal joint that cancels out vibrations
caused by driving power being transmitted
through an angle.
Core plugA disc or cup-shaped metal device
inserted in a hole in a casting through which
core was removed when the casting was
formed. Also known as a freeze plug or
expansion plug.
CrankcaseThe lower part of the engine
block in which the crankshaft rotates.
CrankshaftThe main rotating member, or
shaft, running the length of the crankcase,
with offset “throws” to which the connecting
rods are attached.Crocodile clipSee Alligator clip
DDiagnostic codeCode numbers obtained by
accessing the diagnostic mode of an engine
management computer. This code can be
used to determine the area in the system
where a malfunction may be located.
Disc brakeA brake design incorporating a
rotating disc onto which brake pads are
squeezed. The resulting friction converts the
energy of a moving vehicle into heat.
Double-overhead cam (DOHC)An engine
that uses two overhead camshafts, usually
one for the intake valves and one for the
exhaust valves.
Drivebelt(s)The belt(s) used to drive
accessories such as the alternator, water
pump, power steering pump, air conditioning
compressor, etc. off the crankshaft pulley.
DriveshaftAny shaft used to transmit
motion. Commonly used when referring to the
axleshafts on a front wheel drive vehicle.
Drum brakeA type of brake using a drum-
shaped metal cylinder attached to the inner
surface of the wheel. When the brake pedal is
pressed, curved brake shoes with friction
linings press against the inside of the drum to
slow or stop the vehicle.
Castellated nut
Catalytic converter
Crankshaft assembly
Carburettor
Canister
Drum brake assembly
Accessory drivebelts
Driveshaft

Glossary of Technical Terms REF•23
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
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