differential FORD GRANADA 1985 Service Repair Manual

Models covered in this Manual have disc
brakes fitted all round. The footbrake operates
hydraulically on all four wheels, and the
handbrake operates mechanically on the rear
wheels. Both footbrake and handbrake are
self-adjusting in use.
Ford’s anti-lock braking system (ABS) is
fitted to all models. The system monitors the
rotational speed of each roadwheel. When a
wheel begins to lock under heavy braking, the
ABS reduces the hydraulic pressure to that
wheel, so preventing it from locking. When this
happens a pulsating effect will be noticed at
the brake pedal. On some road surfaces the
tyres may squeal when braking hard even
though the wheels are not locked.
The main components of the system are the
hydraulic unit, the calipers, pads and discs,
the wheel sensors and the “brain” or control
module. The hydraulic unit contains the
elements of a traditional master cylinder, plus
an electric motor and pump, a pressure
accumulator and control valves. The pump is
the source of pressure for the system and
does away with the need for a vacuum servo.
The hydraulic circuit is split front and rear,
as is normal practice with rear-wheel drive
vehicles. In the event that the hydraulic pump
fails, unassisted braking effort is still available
on the front calipers only.
Warning lights inform the driver of low brake
fluid level, ABS failure and (on some models)
brake pad wear. The low fluid level light
doubles as a “handbrake on” light; if it
illuminates at the same time as the ABS
warning light, it warns of low hydraulic
pressure.
ABS cannot overturn the laws of physics:
stopping distances will inevitably be greater on
loose or slippery surfaces. However, the system
should allow even inexperienced drivers to
retain directional control under panic braking.
From August 1986 the following
modifications were made to the braking
system.
a)The relays differ from earlier versions.b)The hydraulic pump is constructed of iron
rather than alloy.
c)A new pressure warning switch is used.
d)The earlier high pressure rubber hose is
replaced by a steel pipe.
To overcome the problem of excessive rear
brake pad wear, Ford introduced a differential
valve which is screwed into the ABS valve
block.The valve limits the pressure applied to
the rear brake calipers and so reduces brake
pad wear. From 1988 onwards, the valve has
been fitted during production. The differential
valve can also be fitted to earlier models. Refer
to your Ford dealer for further information.
From April 1992 onwards, the models
covered in this Manual were equipped with a
new Teves MK IV anti-lock braking system
instead of the Teves MK II system fitted to the
earlier models.
The Teves MK IV system differs from the
earlier MK II system in the following ways.
a)The source of hydraulic pressure for the
system is a conventional master cylinder
and vacuum servo assembly.
b)A valve block and pump assembly is used
instead of the hydraulic control unit. The
block contains the inlet and outlet
solenoid valves that control the hydraulic
system. There are three pairs of valves,
one for each brake circuit (paragraph c).
c)The hydraulic braking system consists of
three separate circuits; one for each front
brake (which are totally independent of
each other), and a joint circuit which
operates both rear brakes.
d)A G (gravity) switch is incorporated in the
system. This is an inertia type switch and
informs the control module when the
vehicle is decelerating rapidly.
e)A Pedal Travel Sensor (PTS) is fitted to the
vacuum servo unit. The PTS informs the
control module of the position of the brake
pedal when the anti-lock sequence starts
and ensures that a constant pedal height
is maintained during the sequence.
The MK IV system operates as follows.
During normal operation the system
functions in the same way as a non-ABS
system would. During this time the three inlet
valves in the valve block are open and theoutlet valves are closed, allowing full hydraulic
pressure present in the master cylinder to act
on the main braking circuit. If the control
module receives a signal from one of the
wheel sensors and senses that a wheel is
about to lock, it closes the relevant inlet valve
in the valve block which then isolates the
brake caliper on the wheel which is about to
lock from the master cylinder, effectively
sealing in the hydraulic pressure. If the speed
of rotation of the wheel continues to decrease
at an abnormal rate, the control module will
then open the relevant outlet valve in the valve
block; this allows the fluid from the relevant
hydraulic circuit to return to the master
cylinder reservoir, releasing pressure on the
brake caliper so that the brake is released. The
pump in the valve block also operates to assist
in the quick release of pressure. Once the
speed of rotation of the wheel returns to an
acceptable rate the pump stops, the outlet
valve closes and the inlet valve is opened,
allowing the hydraulic master cylinder
pressure to return to the caliper which then
reapplies the brake. This cycle can be carried
many times a second. The solenoid valves
connected to the front calipers operate
independently, but the valve connected to the
rear calipers operates both calipers
simultaneously.
The operation of the ABS system is entirely
dependent on electrical signals. To prevent
the system responding to any inaccurate
signals, a built-in safety circuit monitors all
signals received by the control module. If an
inaccurate signal or low battery voltage is
detected, the ABS system is automatically
shut down and the warning lamp on the
instrument cluster is illuminated to inform the
driver that the ABS system is not operational.
Whilst in this state the system functions in the
same way as a non-ABS system would. If a
fault does develop in the ABS system, the car
must be taken to a Ford dealer for fault
diagnosis and repair. The system is equipped
with a diagnostic plug into which a special
diagnostic (STAR) tester can be plugged. This
allows faults to be easily traced.
1General information
10•2Braking system
Torque wrench settingsNmlbf ft
Front caliper:
To stub axle carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 to 6138 to 45
Slide bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Rear caliper:
Bracket to carrier plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 to 6138 to 45
Slide bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 to 3523 to 26
Hydraulic unit to bulkhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 to 5130 to 38
Accumulator to pump body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 to 4526 to 33
Pump mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 to 95 to 7
High pressure hose banjo bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 to 2412 to 18
Reservoir mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 to 63 to 4
Wheel sensor fixing bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
Vacuum servo unit retaining nuts (Teves MK IV) . . . . . . . . . . . . . . . . . .35 to 4526 to 33
Master cylinder retaining nuts (Teves MK IV) . . . . . . . . . . . . . . . . . . . . .20 to 2515 to 18
Valve block and pump assembly mounting nuts (Teves MK IV) . . . . . . .21 to 2815 to 21
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REF•12Glossary 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 that
would 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.
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.
Canister
Brake bleeding
Bearing
Air filter
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REF•14Glossary of Technical Terms
GGapThe distance the spark must travel in
jumping from the centre electrode to the side
electrode in a spark plug. Also refers to the
spacing between the points in a contact
breaker assembly in a conventional points-
type ignition, or to the distance between the
reluctor or rotor and the pickup coil in an
electronic ignition.
GasketAny thin, soft material - usually cork,
cardboard, asbestos or soft metal - installed
between two metal surfaces to ensure a good
seal. For instance, the cylinder head gasket
seals the joint between the block and the
cylinder head.
GaugeAn instrument panel display used to
monitor engine conditions. A gauge with a
movable pointer on a dial or a fixed scale is an
analogue gauge. A gauge with a numerical
readout is called a digital gauge.
HHalfshaftA rotating shaft that transmits
power from the final drive unit to a drive
wheel, usually when referring to a live rear
axle.
Harmonic balancerA device designed to
reduce torsion or twisting vibration in the
crankshaft. May be incorporated in the
crankshaft pulley. Also known as a vibration
damper.
HoneAn abrasive tool for correcting small
irregularities or differences in diameter in an
engine cylinder, brake cylinder, etc.
Hydraulic tappetA tappet that utilises
hydraulic pressure from the engine’s
lubrication system to maintain zero clearance
(constant contact with both camshaft and
valve stem). Automatically adjusts to variation
in valve stem length. Hydraulic tappets also
reduce valve noise.
IIgnition timingThe moment at which the
spark plug fires, usually expressed in the
number of crankshaft degrees before the
piston reaches the top of its stroke.
Inlet manifoldA tube or housing with
passages through which flows the air-fuel
mixture (carburettor vehicles and vehicles with
throttle body injection) or air only (port fuel-
injected vehicles) to the port openings in the
cylinder head.
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 to
the 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.
Adjusting spark plug gap
Plastigage
Gasket
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