
CONTENTS
Pecp
Cneprpn
I.-SrenTING
THE ENGINE
AND
Dnrvrwc
rnr Can 2r
Starting
the Engine-use
of
Starting
Handle-Automatic
Gear
changing-Tow
starting-Fuel
Feed-l.-uel
Gaug_e-chassis
Lubricaiion-Controllable-
Shock
Dampers-Battery
Charging-
Lighting
control and
switch-Accessories-Engine
Thermostat
ani Thlermometer-Coolant
Level
in
Radiator-Frost-Fitting
of
Snow
Chains.
Cseprnn
II.-PnnIoDrc
LurnrcerloN
AND
ATTENTIoN
27
Lubricants
Recommended-Capacities-Points
for
Regular
Atten-
tion according
to Use of
Car-Adjusting
Valve
Rocker
Clearances.
Cneprrn
III.-CnNTRALTsED
CHASSIS
LUBRIcATIoN
General-Foot-operated
Oil
Pump-Drip
Plugs.
35
Cneprnn
IV.-ENGINE
LusntcerloN
Svs:rcna
39
Filling
the System-Oil
Pump-Oit
Filter-Crankshaft
and
ConnJcting
Rods-Relief
Valves-Valve
Rockers,
Push
Rods
and
Tappets-tamshaft-Oil
Sump-Oil
Level
Indicator-Oil
Pressure.
Cneprrn V.-Tsn
FuBr
Svsrnu
The
Fuel
System-Fuel
Pumps-Faulty
Operation
of
Pumps-Fuel
Tank-Fuei
Filters-Fuel
Gauge-The
Carburetters
(Action)-
Automatic
Air
Valve-Throttle
eontrol-Automatic
Choke
Control
-Float
Feed
Mechanisms-Further
Dismantling
of
carburetter-
Adjustment
of
controls-setting
of
Idling-
Adjustments-Air
Cle-aner and
Silencer
(Standard
Type)-Air
Cleaner
and Silencer
(Oil
Bath Ttpe).
45
57
Cneprnn.VI.-Tur
BnexrNG SYsTEM
General
Description-Possible
Variations-Adjustments-A.djust-
ment of
Harid
Brake-Adiustment
of
Servo-Lubrication-
Bleeding
the Hydraulic System-Hydraulic
Master
Cylinder.
CnaprnR
VII.-GrARBox,
Pnopnr,ER
SHAFT
AND
REAn
AxrB...
The
Gearbox-Universal
Joints-
Rear Axle'
Cneprnn
VIII.-STEERIN6,
SnOcr
Deupnns,
Rortn
Srntucs,
WsBBr,s AND
TYREs
67
Steering
Box
and
Column-steering-Front
Suspension-lilarning,
Front
-suspension
Springs-steering
Arms-and-Joitlt:Front
Stabiliser-lRear
Hydiaulic Shock
pampqlg-Rear
Road
Spjings-
Wheels-Wheel Discs-Lubrication
of-
Wheel
Bearings-Tyres-
The
Jacking
System-Wheel
Changing-Fitting-
and
Removing
Tyre{-Inflatjon
of
Tvres-Balaucing
Road
Wheels.
6s

Contents-continucd.
Pecp
CgeprBn
IX.-EIIGINE
Coor,rxc
Sysrnu
...
...
..,
...
79
coolant-coolant
Pump
and Fan-Fan
Belt
Adjustment-ovor-
heating-Engine
Therniostat-Radiator
Mounting-Frost and
Anti
freeze Mixtures-Car
Heater.
Cneprrn
X.-Tlln
Er,BcrnrcAl-
SYsTEM
...
o..
85
.General-Dynamo-Fuse
Box-Output
Re_gulator and
cut-out-
Switchbox
--
Ammeter
-
Battery
-
First
Charge
-
Topping-Up-
Specific
Gravity
of
_Electrolyte-charging-_
charging
pattery
from
oirtside
sourc6-Maintenance-Ignition-Ignition
coil-Ignition
Timing-Firing
order
of cylinders-spark-ing
__Plugs- ltarter
Motor--starter
Motor
Switch-Micro-switch-use
of
starter
.
Motor-Electric
Fuel
Pumps
and
Gauge-Electric
Horns-De-
misting
Equipment-Electrical
Fault
-Location-Recommended
Lamp
-eulUi-Headlamps-Replacing
a.Headlamp
g"t-
4Igning
the
i{eadlamps-The
Si-de
Lamps-Radio-To
set
up
The Tuning
Push
Buttons.
Cneprrn
XI.-Tss
Bonv
AND
CoAcHwoRK
...
ro5
General-Windscreen
Washing-Washing
and
Polishing-Doors-
Seat
Slides-Upholstery
and
earpets-sliding
Roof-Luggage
and
Spare
Wheel Compartrnents-Tools.
CneprBn
XII.-SIoRAcE
AND REcoMMISsIoNINc
oF CARs
III
Cneprpn
XIII.-BENTLEY
Scnoor,
or
INSTRUcTToN
II3

8
Tue
'R'
TypB
BBNrrny.
Camshaft
Carburetter,
Action
of
Carburetter,
Adjustment
Carburetter,
Automatic
Air
Valve...
Carbnretter,
Float
Feed Mechanism
Carburetter,
Needle Valve
Centralised
Chassis
Lubrication
Chains
on Road
Wheels
Changing
Gear
.Changing
a
Wheel
Chassis,
Leading
Particulars
of
Chassis
Lubrication,
Centralised
Coil,
Ignition
Cold
Weather,
Water
in
Cooling
Condenser
of
Contact
Breaker
System
,,.26,
Connecting
Rcids
Contact
Bieaker
Control
Mechanism,
Lubrication
of
Coolant
Level
in
Radiator
...
..i
...25,
Coolant
Mixture
Coolant
Temperature
Crankshaft
Cut-out,
Automatic
Cylinders,
Firing
Order
of
Dampers,
Hydraulic
Shock
Pecn
42
48
52
30,
49
52
5o
35
z6
22
73
r7
35
93
8r
92
4r
92
3r
79
8r
8r
4r
87
95
Dampers,
Governor
for
Hydraulic
Shock
De-froster
arrd
De-mister,
Operating
Distributor,
fgnition
Doors
24,
32,
68, 69
7o
97
92
r07
3I
26,
8z
37
33,
86
86
86
87
85
48, 97
97
85
33,
Draining
Engine
Draining
Cooling
Crankcase
System
Drip
Plugs
Dynamo
Dynamo
Erushes
Dynamo
Connections
Dynamo
Output
Regulator
Earth
Connection
of Batterv
Electric
Fuel Gauge
Electric
Horns
Electric
Lighting,
Starting
and
Ignition
System
23'

INoBx.
Electrical
Fault
Location
Electrolyte,
Inspection
of
Engine
Cooling
System, Capacity
...
Engine Lubrication
System...
Engine,
Quantity
of Oil
in...
.;.
Engine,
Starting
the
Fan,
Engine
Cooling...
Fan
Belt
Adjustment ...
Filler Plug,
Gearbox
Filling
Rear
Axle
Casing
Pecs
g8
30,
90
z8
39
zB
2T
8o
8o
28,
30'34'
3r, 34,
64
65
40
47
95
52
8r
46
45
97
e7
47
47
87
87
98
87
87
63
27
z8
22
Filter,
Engine
Oil
...
30,
Filter,
Cleaning
Fuel
Firing
Order of
Cylinders
Float
Feed Mechanism,
Carburetter
Frost, Precautions
during
...25,
Fuel,
Failure
of
Supply
of
Fuel
Feed
System
...23,
Fuel Gauge
Fuel
Pumps
Fuel Filters
Fuel
Tank
Fuse
Box
Fuse Wire
23,
48,
Fuses,
Failure
of
Fuses, Replacing
Fuses,
Spare
Gearbox
27,
3c
,
34,
Gearbox,
Oil for
Gearbox,
Oil
Capacity
of
Gqar
Changing
Glycol
in
Cooling
System
...25,
Governor
Controlling
Hydraulic
Shock
Dampers
Greases,
Recommended
HeadlEmps
Headlamps,
Alignment
Headlamps,
Replacing
Bulb
Heater,
Car
Iforns,
Electric
I{ubs,
Wheel
79
7r
27
roo
t02
roo
8z
97
7r
6r
Hvdraulic
Brakes
Bleedin

IO
Tnn
'R'
TvpB Brurrny.
Hydraulic Shock Dam
Hydraulic Master Cyli
pers ...
24,
32,
nder ...
assrs
...27,
39
27,
30,
63
Prcp
68,
69
33,
62
92
27
34,
65
72
r09
99
Ignition,
Battery
Ignition Coil
93
Ignition
Plugs...
...
3r,
95
Ignition
Sv-itch
Ignition,
Timing
zt,
24,8g
Instruction
Class,
Bentley
Jack,
Portable
Wheel
'Joints,
Universal
...32,
64
Lamp
Bulbs,
Recommended
99
Lamps,
Head ...
roo
Lighting
Control
...24,
89
Lubricating
Oils and Greases
Recommended
27
Lubrication,
Centralised Ch
Lubrication,
Engine ...
Lubrication,
Gearbox
Lubrication,
Periodic
Lubrication,
Rear
Axle
35
28,
3T,
Lubrication,
Wheel
Bearings
Luggage
and Spare Wbeel ...
Missing
Fire
Motor,
Servo
6r
Motor,
Starter
...32,
95
Oil in
Engine,
Quantity
of ...
z8
Oil in
Gearbox and Back
Axle
z8
Oil Level Indicator,
Engine...
Oil Pressure
Oil
Relief
Valve
Oil
Relief Valve, Dismantling
Oil
Pump, Chassis
Oil
System,
Engine
Oils Recommended
for Bentley
Cars
Output
Regulator,
Dynamo...
Overheating
Pivots,
Steering
Plugs,
Standard
Settings lor
Propeller
Shaft Sliding
Joint
93
I13
72
43
43
4r
4r
37
39
27
87
8o
69
"'3r'
95
"'?2
64

IunBx.
IT
Pump,
Engine
Oil
Pumps,
Fuel
Pump,
Coolant
Radiator,
Draining
Radiator
Mounting
...
Radiator
Thermostat
Radiator,
Coolant
Level
in
"'
z5' 8t
Radio
Rear
Axle,
Quantity
of Oil
Replacing
a
Headlamp
Bulb
Road
Springs,
Lubrication
of
Road
Wheels,
Balancing
Rocker
Shaft ...
Rockers,
Valve
Seat
Slides
...
Service
Facilities
Servo
Motor,
Action
of
Servo Motor,
Adjustment
of
Slow Running..
Sliding Roof
Snow,
Use
of Chains
for Driving
on
Spare
Wheel
Compartment
...
Spark
Gaps,
Standard
Spring
Shackles,
Lubrication
of
Springs,
Road
Stabiliser,
Front
Starter
Motor
...
Starter Motor
Bearings
Starter
Motor
Brushes
Starter
Motor
Connections
...
Starter
Motor,
Failure of
Operation
of
Starter Motor
Lubrication
Starter Motor
Switch
Starter Motor,
Use
of
Starting,
Control Settings
{or
25'
Pear
40
46,
97
8o
26,
8z
8r
29,
79
r03
zB
IOO
7r
7s
42
42
ro8
r6
57
6r
I02
52
r09
z6
r09
3I,
95
36,
7r
7r
6g
32,
95
95
95
g6
q8
32,
96
96
g6
Shock
Dampers,
Hydraulic
...
24,
32,68,69
Side
Lamps
Starting
the
Engine
Steering
Box,
Oiling
Steering
Joints
29,
3t,
2l
2l
67
6g

INoBx
or IrrusrRATroNS.
r3
INDEX
OF ILLUSTRATIONS
Frc.
Pecp
No.
No.
Adjusting the Inlet
Valve Rocker
Clearances...
Air Cleaner-Standard
Type
Air Cleaner-Oil
Bath
Type
Axle
Casing, Rear
I3ox,
Fuse,
Output Regulator
and
Cut-out
Brakes,
Adjustment
of
Front
Brakes,
Adjustment
of
Rear
Braking
System, Diagram
of
Carburetters, in Position
on
Carburetter,
Exploded
View
Engine
Chassis Lubrication
System, Diagram
of
Chassis
Oil
Pump ...
Contact Breaker and
Distributor
Contact Breaker, Interior
View
Controls,
Driver's
Controls,
Radio
Crankcase Drain Plug
Damper, Rear Hydraulic
Shock
Diagram of Braking
System
Diagram, Electrical
Wiring
Door Hinges
Drain
Tap Cylinder
Jacket
Dynamo
Engine Lubrication
System
Engine Oil Filler
Cap and
Dipstick
Engine Oil, Relief
Valves.
Entered
Stud
at
Top
Fan
Belt
Adjustment
Filter, Rear
Fitting
Jack
to
Slide
Front
Brake
Adjustment
Front
Compartment Picnic
Table
Front
Hub and
Wheel,
Section
of
Fuel Pumps...
3
r5
r6
2+
42
r8
r9
t7
I3
I4
J
4
43
4+
I
5o
IO
27
r7
4o
53
38
4r
6
9
33
37
t2
z8
r8
s4
35
II
42
32
53
54
66
88
6o
6o
56
48
5o
36
35
93
94
20
r03
43
7o
56
85
ro8
8z
86
39
39
42
74
8o
47
73
6o
ro8
76
45
88
Fuse
Box, Output
Regulator
and
Cut-out

r4
TnB
'R'
Tvpn BBrstrnv.
Gearbox
Access
Points
Gearbox,
Underneath
View
Gear
Range Selector
Lever
Guide
to
Crewe Service Station
Guide
to Main Service Station
Headlamp, Changing
the
Heater Isolating Tap
Hydraulic Shock
Damper,
Front
Hydraulic Shock
Damper,
Rear
Elydraulic
Master Cylinder and
Bulb
58
rr5
57
IT4
47
IoI
3e
83
z6
68
27
20
+5
5
6
Frc.
No.
2T
22
2
Prcr
No
63
64
22
94
36
39
IIO
95
73
40
42
73
73
65
35
r03
6o
77
32
74
68
7o
6r
Lubrication System,
Lubrication
System,
Luggage and Spare
Ignition Coil
Chassis
Engine
Wheel Compartment
Motor,
Starter
Mounting
Rear Wheel
Oil
Filter
Oil
Relief Valves, Engine
Operating
Wheel
Jack
Positioning Rear
Wheel
Propeller
Shaft
Pump, Chassis Oil...
Radiomobile Controls ...
Rear
Brake
Adjustment ...
Rear Hub and Wheel,
Section of
Rockers, Adjusting Valve...
Rotating Front Wheel
Shock
Damper, Front Hydraulic
Shock
Damper, Rear Hydraulic
Reservoir
56
46
3o
8
9
29
3r.
23
4
5o
i9
36
3
32
z6
Side
Lamp
Side
Lamp
Starter
Motor
Steering
Column
Upholstery,
fnterior
Wheel
Balance
Weights
Windscrepn
Washing Equip,ment
Windscreen
Washer,
Reservoir
and Pump
Wiring
Diagram, Electrical
27
70
48
ro2
49
ro2
46
95
25
67
55
ro9
34
76
5r
ro5
52
ro6
40
85

LEADING PARTICULARS OF
CHASSIS
Engi ne,
Six
cylinGers,
3&"
(gzm/m.)
bore,
4t"
Fr4m/m.)
stroke,
4,566
c.c.,
cubic capacity.
Mono-bloc
casting, detachable cylinder head, overhead
inlet
valves,
side exhaust valves.
Aluminium alloy
pistons.
Engine Lubrication.
Pressure feed to all
crankshaft
and
connecting
rod
bearings.
Relief valve,
providing
positive
low-pressure supply to the valve
rocker shaft,
from
which
the
inlet
valves,
push
rods and tappets
are
lubricated.
Two-gallon
capacity
sump.
Ganburetten.
Two
special type
S.U.
Air intake silencer and air
cleaner.
Fuel
System.
Eighteen-gallon
tank at rear of chassis.
Supply
by
electric
pumps.
Fuel level
gauge
and
warning light on
instrument
board.
The
warning
light
indicates
when fuel is
low.
Cooling
Systotn.
By centrifugal
pump
circulation and fan.
Thermostatically
contrblled.
Coolant
temperature
thermometer
on
instrument
board.
Electrical Equipment,
Twelve-volt
system
with automatic
regulation
of
dynamo output.
Starter
motor
with reduction gear
and
pinion providing
gentle
engage-
ment. Battery of
55
ampere-hour capacity.

Geanbox,
Four forward
speeds and
reverse. Fully automatic
with over-
riding
hand and
"kick-down"
change
speed control.
Glear
Ratios.
Rear Axle rst
znd
3rd
4th
Speed.
Reverse.
Ratio.
Speed.
Speed. Speed.
(Direct.)
3,I3:r
14.23:r
g.8z:t
5.4:r 3.I3;r
t6.o4:r
Rear Axle.
Semi-floating type.
Hypoid
gears
with differential.
Torque and
brake reactions
taken
by
road
springs.
Rear
Suspeneion.
Semi-elliptic
springs in combination
with controllable
hydraulic
shock
dampers.
Fnont
Suspension.
Independent;
open
helical
springs
in
combination
with hydraulic
shock
dampers.
Steering.
Cam-and-roller
type.
Bnakes.
Hydraulic
operation
on front
wheels, mechanical
operation
on
rear
wheels assisted
by
mechanically driven
servo
motor.
Hand
brake
operates
on rear
wheels.
Chassie
Lubrioation.
Centralised
chassis
lubrication
system supplied by foot-operated
pump
and
reservoir
on
dashboard.
Road Wheele,
Detachable
steel
wheels, fitted
with 6.5o"
by
16' India
Super
Silent Rayon
tyres.
r8

Dimensions.
Total
length
overall,
Width
of
car ...
Wheelbase
Track-Front
...
Rear
Turning
circle...
Weight
(kerbside)
Overall
height
including bumpers ...
38$
cwts.
r6',
7t"
5'
r.o"'
ro' oo
4'
8+"
4'
Tot"
4T'
20
(approx.
).
5'
5f"
Ghassis
and Engine Numbers.
The chassis
number will be
found
on the
identification
plate
fixed
.to
the front of the dashboard
under the
bonnet, and
also
stamped on
the left-hand
side frame
member
just
in front of
the dashboard, under
the bonnet.
The
engine number is stamped
either on the
front left-hand
crankcase
lifting lug, or on
a boss on
the crankcase above
the front
left-hand
lifting lug.
r9

20
TsB
'R'
Typn
BsNruBy.
f3l4l
?o lB
19
2l
Fig.
1.-GENERAL
VIEW
OF
DRIVER'S
CONTROLS.
1.
Steering
wheel.
2. Gear
range
selector.
3.
Ride
control.
4.
Hand
brake.
5.
Side
scuttle
ventilator.
(Pull-open,
push-shut).
6, Accelerator
pedal.
7. Brake
pedal.
8. Dip-switch.
9.
Cigar
lighter.
(Push-in,
lighter
springs
up
when ready
for use.)
10.
Instrument
lights.
(Pull-on,
push-off.)
11. Screen
wiper
switch.
(Turn
clockwise,
first
position-normal,
second
position-fast.)
12.
Fuel
warning light.
(Steady
glow
at 2-3
gallons
reserve.)
13.
Oil level
indicator. (Press
button
and read
on fuel
gauge
dial.)
14.
Direction
indicator
warning
light
(when
fitted).
15.
Map lamp
switch.
(Push-on,
push-off.)
15. lgnition
warning
light.
17.
Trafficator. (Self-cancelling.)
18. De-mister
booster
fan.
(Turn
clockwise,
first
position-fast,
second
position-slow.)
19,
Fog
lamp.
(Pull-on,
push-off.)
20. Rear window
de-mister.
(Pull-on,
push-off.)
21
Heater.
Turn
clockwise,
first
position-fult
on,
second
position-medium.)

Srenrrwc
rnn
ENcTNE
AND Dnrvrxc rnn
Cen.
2l
CHAPTER
I
Starting
the
Bngine
and
Driving
the
Car
_,
Starting
the
Engine-Use
of
Starting Handl,e-Automatic
Gear
C h
an
ging
7-T
ou
S t
ar ting
-F
u
el,
F
e
ed-F
u eI G aug e-C
has
si s Lub
r i cati
o n
-c
ontr
ol,l,abl
e S
ho ck D
arnp er s-B
att ery C
har
ging-Li
ghting
C ontr
ol,
and
Suitck-Accessories-Engine
Thermostat
anA- Theirnomiter-Coolant
Leael,
in
Radiator-Frost-Fitting
of
Snoa Chains.
Starting
the Engine,
Switch
on the ignition
by turning
master
and ignition
switches
on
the instrument
board to On.
The
master
switch
controls all the
electrical
system, excepting
the
electric
clock, inspection
and
roof
lamps,
the latter
being left
always
available
for convenience
when
entering the
car in
the
dark.
A small red
warning light
on the instrument
board
will
be illumi-
nated
when the ignition
is
switched
on, but
will be
extinguished
when
the engine
speed is
sufficient
to
cause the
cut-out
contacts
to
close.
Ensure
that the
gear
lever
on
the steering column
is
in neutral,
quadrant gear
position
"N",
as
it is only
in this
position
that
the
starter
switch is
operable.
Before
starting
the
car
in
temperatures
aboae
freezing point,
f,rst
defress
the accel'erator
pedal,
slightl,y and
tken al,loa
it to
return
t6 its
norrnal
position.
This permits
the
throttle stop on
the carburetter
to
re-position
itself correctly
according
to
engine temperature.
-
Under v_ery cold
conditions,
in temperatures
of below
freezing
p-oint,
it
will be necessaly_
to
depress the accelerator pedal
slightlR
about a quarter
of its full
travel, and hold
it
depressed
while the
starter button
is
being
operated. Immediately
the
engine fires,
the
accelerator
pedal
should
be released.
Depress
the starter
button
firmly,
an appreciable
pause
must
be
made
between
the operatign;
of switching
on the
ignition
and,
depressing
tke starter button,
especially
uhen
making a
start
from
cold.
ÂThis
ii
necessary
in
order
to
give
the
pumps
time to fill
the float
chambers
of
the carburetters.
Use of
Starting
Handle.
,
It,is
imperatiae
uhen starting the
cngine
with the
starting
hand,l,e,
that tke
gear
leaer
must be at Neutral,.

SranrrNc
rnn ENcrNr aNp
DnrvING
rnp
Can. 23
It should
be noted that
although the
hand
control lever
may be
set
in
position
"3",
this
gear
ratio
will
not be
held
if
the
engine
revolutibns
are excessive. The
automatic
control
unit
will over-ride
this
setting
and the
gearbox
will automatically
change
up
to
4th
gear.
When
descending
very steep
gradients, the
gear
lever
should
be
placed
in the
and
position.
Onty
at prolonged
halts,
due
to traffrc
jams,
etc.,
is it
necessary
to engage
neutral; at all
ordinary traffic
controls,
the
gearbox may
be left
in
the
gear
range
then
in
use.
Reverse
can be engaged
while the
car
is
travelling
forward
at
any
speed
below
ro
miles
an
hour.
This
feature
can
be
used
to advantage
'should
the
car become
embedded in
deep
snow, when
by suitable
timing
of
the
engagement
of reverse
and second, the
car can be rocked
out of
the
rut.
When the engine
is
stationary,
a
parking lock
is
provided by
placing
the
hand control
lever in
"R".
The steering
column
control lever
moves through
a
"g*.e"
between
positions
"3"
and
"2";this
design
of
quadrant
allows changes
between
4th
and
3rd
speed
ranges to be
made
without
risk of
entering
the
znd
speed
range. Likewise,
changes between znd
speed
range ahd
reverse
when
"shunting"
are facilitated.
It
should
be noted that
when starting
the
car from
cold
the engine
will run at
a
"fast
idle", with
the consequent
build-up
of an operating
oil
pressure
in
the
gearbox. If when
parked in a confined space
it
is necessary
to engage
reverse
gear
from
neutral, thereby temporarily
engaging
the
forward speed
ranges,
care
must
be
taken
not
to
release
the
brakes
until the
gear
lever is
in
position
"R".
Tow
Starting.
If it
should
be
necessary to start the
car by towing, the
gear
lever
should be placed at
position.
"2".
When the
car speed
reaches about
zo
miles per hour,
the
engine
will start to
turn
over
and fire. The
lever
should
then
be
placed
in
the
neutral
position, and care
should
be
taken
not
to
have the throttle
too
wide
open or
the
car
may
accelerate
too rapidly and
overtake the towing
vehicle.
Fuel
Feed.
Fuel is
supplied
from
the
main
tank to the carburetter by
means
of a
dual
electric
pump
mounted
in
the
frame (see Fig.
11). The
total
cilpacity of the main tank
is
r8
gallons.
Fuel
Gaugo.
The electric
fuel
gauge
on the
instrument board
is graduated
to
register
the total
quantity
of
fuel in the'main, tank. The
gauge
is
inoperative
when the ignition
is
switched off.
Special contacts carried by the tank
unit cause the
green
warning
lamp
to light when only about three
gallons
of
fuel remain in the
tank.

SrenrrNc
rrru ENcTNE
AND DnrvrNc
rnp
Cen.
The
master
switch controls
the
head,
side
and tail
lamps, alternative
On positions
being
provided,
viz.:-
S and
T.-Side
and
Tail
lamps
on.
H,
S and
T.-Head,
Side
and
Tail
lamps on.
FL.-"Parking"
lights on,
e.g. Side
and Tail lamps on,
accessories
off.
In addition, a foot
operated
switch
is
provided,
by
means
of which
the beam
of the
driving
lights
is altered
to allow
anti-dazzle
precautions
to operate, thus extending
courtesy
and
safety to
passing
traffic.
Accessories.
'
Windscreen
wipers, washers and
de-misters
are
fitted,
also
direction
indicators and a car heater,
these being
operated as
under:-
The
windscieen wiper has
two speeds
controlled by a two-position
switch
(see Fig. 1).
Operate
by turning
switch
knob to
the
right:
the
first
position
gives
SLOW,
further
turning
to
the right to the
second
position
gives FAST.
Hard over to the left is OFF.
The
higher speed of
wiping
is intended
for
use during
heavy
rain.
It
should
not be used in heavy
snow or
with a dry or
drying wind-
screen,
i.e. when
the load
on
the
motor is in
excess of normal.
The
windscreen wiper motor is
fitted
with
an automatic
switch
which breaks the electrical circuit if the motor overheats; and this
may
occur if the high
speed
position
is
used when the windscreen
is
nearly
dry, causing a
high resistance to the blade movement.
When
the circuit breaks, the
wiridscreen wiper will stop
but
will restart
if
allowed
to cool
for
about
ro minutes, meanwhile the
switch should be
turned
to the slow speed
or
"off"
position
to
prevent
further over-
loading
unless the rain
is
heavy.
For
washing the windscreen, two small
jets
are arranged on
the
scuttle to squirt
fluid
on
to
the windscreens
within the traversing
arc
of the
wipers.
A press
button on the
facia
should
be
depressed when
required; on releasing,
two
jets
of fluid
will
be
directed
on to the
wind-
screen.
The
screen wipers should then be switched
on
to complete
the cleansing.
For
de-misting the windscreen, warm
air from
a special
heater
under the front
wing
is
taken
through
suitable ducting
to
vents
in the
capping
rail.
The forward motion of the car is normally sufficient to
ensure
adequate,
de-misting. Under severe
conditions, switch on the booster
motor
(18,
Fig.
1
)
.
The
raised arm trafficator type of indicator is
fitted,
and the
control
switch
is mounted on the
centre
of the capping
rail
as
shown
in Fig. r.
A
car heater is
fitted
in the
front
compartment
under
the seat.
A
push-pull
switch
on the facia
(3,
Fig.
2)
operates a
valve to
control the
water
supply
to the heater. A rheostat
switch
on the
facia board (21, Fig. 1
)
controls
the
fan
for
air circulation.

(To
be
inserted in
Bentl'ey
Handbook, No.XIV, to
face
page
27.)
AUTOMATIC GEARBOX.
SERVICE
AFTER
1,(x)O MILES RUNNING.
.
I m
poptant.
During the
early
life of the Automatic
Gearbox, a certain
amount
of initial
bedding-in of the
brake bands occurs. This
cannot
be
compensated for in
the
original factory adjustments, and
it
is
therefore
most
important
that
after the car has completed the first
r,ooo miles
running, it should be
taken to
the Bentley Retailer
in your territory
for the appropriate adjustments
to be carried out.
No charge
will
be made for
this service.
If it
is inconvenient
for you
to send the
car
to the
retailer from
whom
it
was
purchased,
any Bentley
Retailer will be
pleased
to
carry
out
this
adjustment.
Bnxrrrv Morons
(rgSr)
Lro.,
Lottpot*.
Leaflet
S.B.iSblSe.

Ppmoorc
LunnrcerroN
AND
ArrsNrtoN.
27
CHAPTER
II
Periodic
Lubrication
and
Attention
LUBRICANTS
RECOMMENDED
.Eng
i
ne,
For
normal
operation
of the car under
Temperate
climatic
con-
ditions,
Bentley
Motors
(tgfr) Ltd.
recommend
a
first quality
oil oJ
viscosity
S.A.E. zo
tor
the
engine
for
all-the-year-round
use, but,
if,
conditions
permit of long
journeys
of
maintained
high speeds,
a heavier
duty
oil of
S.A.E.
3o
grade
would
provide better
oil
mileages._
Also, it
would
be
advantageous
to use
an S.A.E.
3o
grade oil
when
the
car
is
normally
operated under Tropical
climatic
conditions.
On
the
other hand,
under extreme
Winter
conditions
of sub-zero
temperatures,
the use
of a lighter
grade oil
of
S.A.E.
ro viscosity
would
provide
easier
starting
and satisfactory
lubrication.
The
following oils
are recommended:-
Shell
X.roo-eo
X.roo-3o
Vacuum
Mobiloil Arctic Mobiloil
A.
Equivalent
oils to
the above
are also
marketed by:-Sternol
Ltd.,
Alexander
Duckham &
Co. Ltd.,
Esso Petroleum
Co.
Ltd.,
Gulf Oil
(Great Britain)
Ltd.,
and Dalton & Co.
Ltd.
In
the
instructions
which
follow,
reference
is made
to
oil
"A"
or
"8"
as
above,
i.e. viscosity
zo
or
30.
Gearbox.
The
automatic
gearbox should be
filled and topped
up
only
with
Automatic Transmission
Fluid,
Typ"
"
A",
having an Armour
qualifi-
cation
ttumber
prefixed by AQ/ATF.
Either
of the following
may be used:-
..Att
S.A.E.
zo
B.P.
Energol zo
Wakefield's
Castrolite
..Btt
S.A.tr.
3o
Energol
3o
X.L.
Typ"
AQlATF-ror
Type
AQlATF-ro3
Typ"
A9lATF-z6t
Type A8lATF-r56
Vacuum
Shell
B.P.
Wakefield's
...
General
Motors
Mobiloil Fluid zoo
Donax T.6
Energol Automatic
Transmission
Fluid.
Castrol TQ.
Hydra-Matic Fluid

r
28
Tnn
'R'
Tvps
BBNrrnv.
Rear
Axle.
Wakefield's
Special
Castrol
Hi-press S.C.
(If
this
is unobtainable,
use
a first
quality Hypoid oil of viscosity
S.A.E.
9o.
Do
not
mix these
oils; drain and
refill.)
Garbunetter
Air
Valve Damper,
Viscosity ro
oil;
any
of the following
may
be
used:-
B.P.
Wakefield's
Shell
Vacuum ...
Steering
Box-Ghassis
Oil
Contact Breaken Cam
Pad.
Viscosity
3o
oil, as under
"B"
above.
Hydraulic Shock
Dampens.
Viscosity
zo
oil,
as
under
"A"
above.
Propeller Shaft--Door
Hinges.
Vacuum
Mobilgrease
No.
a.
Distributor
Grease Gup.
High Melting Point
Grease.
Hydraulic
Brake Fluid.
Genuine
Lockheed Hydraulic
Brake
Fluid,
CAPACITIES
U.C.L.
oilit.
Donax
A.r.
Mobiloil
Arctic Special
Pump-Stanter
Motor
Geans-
Engine
Gearbox
Rear Axle
Chassis
Oil Pump
Cooling
System
Fuel
Tank
S.A.E.,
Spec.
70,
R.2.
pints Imp.
approx.
pints I*p.
,,
pints Imp.
,,
pints Imp.
,,
pints I-p.
,,
gallons
I*p.
,,
x6
20
rfr
2
32
r8
GENERAL
In addition to the
points
supplied
with
oil
by the
centralised
system, there
are
others-which, fof
various
reasons,
cannot
be
fed
in
this way
and
must,
therefore,
be
lubricated
by
hand.
In the
notes which follow,
these
poiirts
are classified
as
far
as
possible
under
mileages, or
according
to
the
usage
of the
car.
It
is important
that
careful
attention
should
be
given to
their
lubrication
3o
as to
reduce
wear
and
eliminate
mysterious
squeaks
and
rattles.
Further
notes
are
included covering
the
periodic operations
and
adjustments
which
are
necessary.

3o
TnB
'R'
Tvpr
Bpntrnv.
MONTHLY
7.-Battery.
Check
level of acid
in
each cell
and top
up with distilled
water
if
necessary. Check
more
frequently
when
big
mileages
are covered
or
when
the
car
is being run
during
hot weather.
(Access
door in
floor,
under driver's
seat.)
8.-Brakes.
See Chapter
VI
for
description.
The
brakes
should
be checked every
month
or every
2,5oo
miles,
whichever
is the
shorter.
'
To
check the adjustment,
rotate the
adjusters
in a clockwise
direction
until
obvious
resistance
is felt. This
resistance
should
be
equal
for all four
brakes, and
should
the last
"click" on
any
one adjuster
require noticeably
greater
force to
obtain,
this
adjuster
should
be
turned
back
to the
previous "click".
(See
page
59.)
9.-Gearbox.
Run
the
engine for three
minutes
and whilst
still
running
inspgct
the
fluid
level in
the
gearbox
by
means
of
the
dipstick.
(See
Fig.
21.)
If
necessary, repleniih with
one
of
the
recommended
Automatic
Transmissioh
Type
"A"
Fluids, to the
level
marked
on
the
dipstick.
(See
page
27.)
(Access, remove rubber bung. in
floor
in front
of front
passenger's
seat.)
10.-Garburettens.
Inspect oil
level in oil reservoir
of automatic
air valve
guide,
and
top
up
with
the recommended oil.
(See
page
28.)
11,*Oil Bath Air Gleaner.
Every
r,ooo
miles
the
oil
container
and
the
filter
element
should
be removed by
unscrewing the
long
bolt
(1,
Fig.
16)
which
passes
through
the
top of
the silencer.
The oil
container should be
emptied
and
carefully
cleaned,
the
filter
element
being thoroughly
washed
in
petrol
and
allowed
to dry.
Replace the element
and refill the
oil
container
with
oil
"A" to
the
indicated level, and
refix
in
position.
NorB.-The cleaner
should be serviced
at more
frequent
intervals
if
the car is
being
operated
under very dusty
conditions.
(See
page
54.)
Lubrication
and
Maintenance
EVERY
5,000
MILES
l.-Engine
Oil Filter.
Remove
felt element
and washers,
and
discard.
Replace
with
new
element
and
washers.
Refitl bowl with
oil,
re-assemble
and check
that
cover
joint
is oil
tight.
(See
page
4o.)
(Filter
on
right-hand side of engine
crankcase.)

Pnnroorc
LusRrcerroN
AND
ArmNnoN.
Before
commencing
to
adjust a
tappet,
it
should be
ascertained
that
the lower
tappet
operating
the
push
rod is
on the
base
circle
of
its
o_perating
cam.
This is best
don-e by
turning the crankshaft
by
hand
until the
valve
has opened
and closed,
and then cranking
round
balf a,,revolution
beyond
this
point.
The ball
ended
contact
screw (3)
is
screwed
into
the rocker
and
locked
with a
nut (4).
On
releasing,.the
nut the
screw can be
turned
by
means of
the
special spanner
provided.
The correct
clearance
for
the
inlet
rockers is
.oo6"
(.tyz
m/m.).
A feeler
gauge
is provided
in
the tool kit, and is
shown in
position
(6),
.
for
measuring
the
clearances.
As
each
contact
screw is
adjusted, its
locknut
should
be securely
tightened
up.
The correct
clearance
for
the exhaust
tappets
is
.ore'
(.3o5
m/m.|,
with
the engine
cold.
These
should
need no
attention between
dd-
carbonising
periods
of
the
engine.
5.-Air
Gleaner
(Standand
Type).
Remove
cleaner
element
lrom front
end
of silencer,
after unscrewing
the
wing-nut
and
taking off
end cover.
Carefully wash
element ii
petrol
or
paraffin
and
afterwards
oil
with
oil
"A".
Drain
off
excess
oil
before refitting.
It should
be
noted
that if
the
car
is
being
run
under
particul"tly
dSsty
conditions,
the element
may nped
cleaning
more
-frequently.
(See
page
53.)
$.-p69pg.
Oil lock bolts
and
hinges
with
oil
"A".
(See page
ro7.)
7.-Hydraulio
Mast6r
Gylinder.
Remove
the filler plug
(1
),
Fig. 20,
and check
the fluid level, top
up.if necessary
with
the
recommended
fluid
(see
page
z8) so
as
to
maintain
the level
at
one inch
below
the
filler
cap.
(Access
through
trap
door to battery.)
EVERY
20,000
MI.LE8
1.-Dynamo,
Inspect
brushes for
wear; to do
this, unscrew
securing screws
and
remove
cover
to
expose brushes.
(See page
86.)
If renewal
is necessary,
remove
dynamo, clean out
dust
and refit
new
brushes,
making
sure that they
are bedding
correctly
on
t[e
commutator.
Refit
dynamo.
c
33

CBNtneusED
Cnassrs
Lunnrc.A,tloN.
37
Foot-operated
Oil Pump.
The
chassis
oil
pump
is
shown
in
Fig.
4.
to
the system
is necessary
beyond filling of
correct oil
(see page
z8),
after
removal
of
Normally
no attention
the reservoir
with
the
the filling
plug
(2),
as
directed on
page
29.
It should
not be filled
above one
inch
cover.
fiom
the
top
of the filler
When
the
reservoir is
nearly empty it wil be
found
that
the
pedal
returns instantly
after depression,
due
to
the
presence
of air in
the
system.
On
the other hand,
if
the
pedal
takes
an abnormal
length
of time
to
return
to its raised
position,
this
may
indicate
that the felt
strainer
located at the bottom of
the
reservoir is
choked.
Under these
circum-
stances a new
felt
strainer must be fitted.
This
is
arranged
at
the
bottom
of the
resgrvoir,
and is
removed
by
disconnecting the two unions
(3),
and unscrewing
the
cap
(4).
An
aluminium
distance washer, the
felt
strainer
pad,
and
a
wire
ga:uze
support
can
then be taken out.
When
replacing the
parts,
the wire
gauze
support
should be refitted
in the cap
first, followed
by a new f.elt
pad
and, linally,
the
aluminium
distance washer
with
its
recessed
face
towards
the
felt fad,.
Packing
washers
are
provided
on either side of the aluminium
washer,
and it
should
be observed
that these
are in
position.
Normally,
the
felt
strainer
pad
should
be
discarded
and
a new
one
fitted
every
2o,ooo
miles, as directed on
page
34.
It
should never
be
necessary further
to'dismantle the
pump.
Dnip
Plugs.
The
drip
plugs
are non-adjustable
and non-demountable,
and are
lettered
and numbered to
indicate
their
shapes and
relative
rates
of
oil
emission
respectively, a higher number indicating
a
greater
rate.
The
drip
plugs
never require cleaning, and,
being
non-demountable,
no attempt
must
be
made
to take them
apart.
If one is
suspected
of
being defective,
it
should be
replaced
with a new plug
of the same
rating.
(See
Fig. 5.)

Tun
'R'
TypB BeNrrBy.
Oil Pump.
A
gear
type pump
mounted
in
the
lower
half of the crankcase is
driven
by means
of a vertically-mounted
shaft
and
skew
gears from
the centre of the
camshaft.
A coupled
extension
of
this shaft
also
drives the ignition distributor.
The oil
intake
from
the
sump is
of the floating gauze filter type,
ensuring
the
collection of
clean oil, free
from
sludge.-
Oil
is
drawn by
the
pump
through
the floating
intake and
delivered
direct to the
full-flow
fiIter.
oil Filter.
The
full-flow
filter
is fitted
on the right-hand
side
of
the crankcase
as shown in
Fig.
8,
and,
as
previously
stated,
oil is fed
direct
from the
pump
to the filter,
and, after passing
through
the filter, is
returned
via
the relief
valves
to the
main oil gallery,
d.s
shown in the diagram-
matic
illustration,
Fig.
6.
Every
5,ooo
miles,
as
directed on
page
3o,
the filter
element should be
discarded
and replaced with a
new
one.
It is not practicable
to clean
the
felt element, and no
attempt
must
be
made to
do so.
As this
operation entails a
certain amount of
dismantling,
it is
suggested
that
this
periodic
maintenance
should
be
undertaken
by
u
qualified
Service Station.
To
remove the
element,
first,
completelyslacken
off the
dynamo
adjustment.
Then
remove
lock
plate
securing
domed
nut
(1,
Fig.
8), unscrew
the
central
fixing bolt
to
release
the filter
bowl and
pass
the
bowl
forward and
upward
between
the
dynamo
and
valance
plate.
Remove
the
canister
from
the
bowl and dismantle by
un-
screwing
the
knurled
nut
from
the
bottom cover. Extract
the
felt element and
the two
felt
washers, discard and re-
place
with new
ones.
1.
2.
Fig.
8.-OlL FILTER.
Domed
nut
on
centre
bolt.
Filter
bowl.

ENcrNr
Lunnlceuon
SYsmu.
4r
Re-assemble
the
canister and
replace
in
bowl;
ensure that
the
rubber
washer
is
in
good condition.
Ititt
bowl
with
oil
and
replace
in
position.
Replace
wiring
clip
and
re-adjust
dynamo
belt.
On
next
running
the engine,
it
should
be
inspected
for oil
leaks
around the
filter
joint.
Grankshaft
and
Gonnecting
Rods.
The
filtered oil
is
conveyed
to the
relief
valves,
from
where
the
main
oil
supply,
controlled
lt approximately
z$
lbs.
per
square
inch,
.is
delivereaio
ine
main
oil
gallery incorporated
in the
crankcase
casting.
From there
it
is
fed
through
oilways
drilled
in the
crankcase
webs
to
each of the seven
crankshaft
main
bearings,
which
are
of
the
copper-
lead-indium
lined steel
shell
type.
The crankshaft
journals
and
crankpins
are
bored
for lightless
and
to act
as
oil
conduits,
the ends
of
the
holes
being
plugged with
steel
caps.
A11 the
main
bearings
have
circumferential
oil
grooves,
and
radial
holes are drilled
in the crank
journals
to
register with
these
grooves.
OiI
from the
main
bearings
passes to
the
bore
of each
journal
through the
radial transfer
holes
in the
crankshaft
and
then
to the
cranklins
through diagonal
ducts
drilled
in
the
crankshaft
webs,
and
so
thiough
radial
holcs to
each
crankpin
big-end
bearing,
these
bearings
-being
of a similar
type
and
material
to
that
of
the main
bearings.
Each connecting
rod
is
drilled
to
convey
oil
to the
gudgeon
pin
bearing,
the drilling
passing
through
the
big-end
bearing
shell.
Small
holes Jre
cross-drilled
into-this
oilway to
allow a
fine squirt
of
oil
to
lubricate the cylinder walls.
Two
radial holes in
the crankpin
ensure
communication,
twice
per
revolution, with
the oilway
up the
connecting
rod.
Thus,
all the
crank-
shaft
and
connecting
rod bearings
are supplied
with
oil
under
pressure.
Relief
Valves,
The
double
relief valve
unit
is
mounted
on
the
right-hand
side of
the crankcase.
(See Fig. 9.)
The two
valves are in
series,
and their
combined effect
is to
regulate
the
pressure
of the main
high-pressure
supply
to the crank-
shaft
and
connecting rod bearings to
approximately
zJ
lbs.
per
square
inch.
Oil
passing
the
high-pressure valve
(2,
Fig. 9) enters-
the
low-
pressure
chamber
and Jrom
there via
a
pipe
(a)
to
the inlet
rocker
shaft.
In
order
to
ensure a
supply
of oil
to the
low-pressure
system
under
all conditions
of
running,-small
slots
are cut
in
the'seating
of
the high-pressure
valve
(2).

42
TnB
'R'
Typr
BBNrr,nv.
If it is
suspected
that the
relief
valves are
not working
properly,
they can
be inspected
by removing
the
plugs
(3 and 2)
above
the low and
high-pressure
valves respectively.
In each case
the valve
spring
will be found retained
on the
plug,
and when
removed,
the
valves
may be lifted
out for
inspection and
cleaning
of
valves
and
seats.
No attempt
must
be nlade
to alter
the spring
settings by
interfering
with the
springs
themselves,
or by varying
the
number
of washers under
the
plugs.
Care must be taken
to replace
all
parts
in
a
perfectly
clean
state.
Valve
Rookers,
Push
Rods
and Tappets
The
low-pressure
oil
supply
from the
relief
valves is conveyed
Fie.
e.-RELIEF vALVEs.
vla a
pipg
ul$ oilway
through
'!r:
[:l'."t"J,?'J."
"",,.
the
cylinder
block
and head
to
s. L.p.
vatve.
the centre
pedestal
of the inlet
t'.
frti
f,":ffi:'lii
"onn".tion.
valverockershaft,whichisdrilled
,..
Reiurn
from filter.
longitudinally, and
also radially,
in
the
plane
of each rocker,
to lubricate
the rocker arm bearings.
The
rocker arms
are also
drilled, the
holes
running through the
bearing
bushes, to lubricate
the
push-rod
ball ends and
the
ends of the
valve
stems.
Each valve
stem is
provided
with
a
pac"king gland, held
in
position
by the inner
valve
spring, which
prevents excess oil
from
percolating
down the valve
guides.
Oil
is returned
from the.rocker
casing
to the
crankcas-e
through
the
push
rod tunnels.
Gamshaft.
The camshaft, driven
by
single helical
gears,
is
carried in
four
plain
bearings,
these being
lubricated
with
high-pressure
oil through
drillings in
the
crankcase
webs.
The
camshdft
driving
gears
are lubricated by
the
jet
in
the wheel-
case, from the
low-pressure
system.

ENcrnB LunnrcerroN
Svsrnu.
43
Fie. I0.-CRANKCASE DRAIN PLUG.
f.
Drain
plug.
2.
Oil
leyel
indicator float unit.
Oil $ump,
Under
normal cir-
cumstances,
and with
proper
attention, the oil
filter will maintain
the
oil in a clean
con<lition.
Owing
to the
risk of
clilution
of the
oil,
how-
ever,
it
is
advisable to
drain
the surnp
and re-
uew the
oil every
S,ooo
rniles, as directed
on
page
30.
To
drain
the oil, a
plug (1 , Fig.
1O) is
pro-
vided in the
crankcase
surnp,
which should
be
unscrewed
and the oil
allowed
to drain out when the engine is
warm.
On
replacing
the
plug,
ensure that the
joint
washer
is sound
and
in
position.
Oil Level lndicator.
In order
that
a quick
check
may
be obtained, the
petrol gauge
on the
instrument
panel
has been
so
arranged that
by
depressing
the switch
(see
Fig.
1), it
will register
the
approximate
quantity of oil
in
the engine suqp.
The
gauge
is
electrically
connected to
a float unit
fitted
into
the
right-hand
side
of
the
crankcase
sump
(2,
Fig.
10.)
The
reading
should be
taken when the
car
is
standing
as
nearly
level
as
possible.
The amount of oil should be
maintained
at
rtFullt',
this
corres-
ponding
with the
r'Maxtt
mark on
the
dipstick, and showing
that
there
is
approximately
16
pints
of oil
present. A red
line on the
gauge
indicates "minimum",
and
the engine should
never be run with
the
oil level below
this mark.
Oil
Pressure,
Unier normal
conditions of engine temperature and speed,
the
instrument
board
pressure gauge
should
read
approximately zg
lbs.
On
starting
the engine
from
cold, however, a higher oil
pressure
will be indicated,
but
this need
not
cause alarm, as the
pressure
will
fall
when
the
engine
becomes warmed up.
When
the engine
is idling
and
hot, the
pressure
may
fall
to 4 lbs.,
but
provided
that
it increases as the
engine
speed
increases,
this
is in
order.

TnB
FuBr Svsrru.
45
CHAPTER
V
The
Fuel
System
The
Fuel, System-Fuel,
Pumps-Faulty
Operation of Pil,mps-Fuel
Tank-Fuel'
Fil'ters-Fuel,
Gawge-The
Carburetters (Actioi)-Auto-
matic
Air Yal,ae--Throttl'e
Control,-Automatic
Choke
Control-Fl,oat
F
eed'
M
echanisms-Further
Dismantling
of
Carburetter-Adjustment
of
Control's-Setting
of
ldl'ing
Adjustments-Air
Cleaner
aid,
Silencir
(Standard
Type)-Air
Cleaner
and,
Silencer (Oil, Bath
Tyfe).
The
Fuel $ystem.
. -The
fuel
supply from
the
r8-gallon
tank
at
the
rear.of
the
chassis
ir Py
means
of a
double
electric pump
(1
and 2,
Fig. 11),
mounted
inside
the
right-hand
side
chassis
frame
member
below
the
rear
floor.
A
pipe is
arranged
along
the
right-hand
side frame
member
conveying fuel
from
the
tank to
the
pumps.
The
pipe
is
seen
at (a).
A
filter is provided
on
this pipe
line,
being
located
on the frame
cross
member
immediately
in front
of the
tank,
as
shown
in
Fig.
12.
Location of
a
filter
on
the suction
side
that
the latter,
as
well
as the
carburetter,
deleterious effects
of
dirt
or
sediment
in
the
of
are
fuel
the
pumps
ensures
protected
from
the
i.
Fuer
pump.
Fig'
11'-FUEL
PUMPS'.
Inret
oioe.
4.
Fuel
pump.
5. Outtei'pipe.
3.
Valve
caps.
6. Supprerldr
condenlers
From the filter
the
fuel
passes
to
the suction
side
of
the pumps,
and is
delivered
to
the carburetter
float
chamber
by
way
of a pipe
(6),'
and
another
filter
located
at
the float
charnber,

46
TnB
'R'
TypB
BBwrrBv.
Fuel Pumps.
The Juel pumps
(1
and
2,
Fig. 11)
are
of
the
electric,
solenoid-
operated,
djlph_1agT
type,
ald
comprise
two
independent
pumps
complete
ryith
diaphragms,
solenoids,
contact
trip
mtchanism!,
and
suction and
delivery
valves.
Fot\
pumps
deliver into
a common
chamber
and
are
simultaneously
rendered
operative
when
the
ignition
and
master switches
are
tronri.
Duplicate
puqps
?re
provided
primarily
to
ensure reliability.
They
also
ensure
that
there
shall
be no
starvation
of fuel
at
maximum
engine
demands.
If
it
should
ever
be necessary
to
disconnect
the
fuel pipes
at
the
pumps,
it
is important
first
to release
the cover
of
the iear
filter.
(See page
47.)
This
will
prevent
loss
of fuel
by
syphoning,
due to
the
location
of
the
pumps
below
the level
of
the inairi
tank.-
The current
supply
for
the pumps
is
taken
through
the ignition
fuse.
Faulty Opcration
of Pumps.
This would
_
cause-
failure,
or
shortage,
of
fuel
supply
to
the
carburetter,
and
may
be
due to
one
or
moie
of the
folowing"c"oter:-
r. Shortage
of
fwel
in-.the
tank.-This
should
have
caused
the
green
warning
lamp
to light,
but
if
the tank
has
been
allowed
to run
dry,-.the pumps
will
tick
continuously
and noisily.
On severe
gradients.
and
side
slopes,
these
symptoms
may
occur
before
the tank is
completely
empty,
due to
surging
of
firel in
the tank,
which
may
uncover
the
suction
pipe.
z.
Air
leak
on
the
suction
side.-Either
at
the
filter
or
on
the
pipe
lin_e.
A
slight air
leak
will
cause
the
pumps
to
work
rather.
faster
than
normal,
but
if _sufficiently
bad
to
tause
a
complete
air
lock,
the pumps
will
tick
continuously
and
noisily
as if
short
of
petrol.
t.
ruy-tf
aal,aes
not se.ating.-
Thg
delivery
valves
do
not give
any
easily
detectabl_e
signs
of
their
functioning.
If a
sucti5n
valvt
is
not
seating,
the pump
will
tick continuo-usly
when
the engine
is
switched
on
but
not
running.
I!
is pro6able
that
forEign
matter
is
lodged
under
one
of
tlie valves.
If the above
is
suspected,
remove
the
caps
,(3,
Fig.
11
),
the
valves
and
valve
cap assemblies
may
their
ni: titte?
oui
and
clgned.
4.
sl,uggish
operation
of
the
pumps,-check
that
the
electrical
connection
and
cont-act
-points
-are
clean
and in proper
order.
Jerify,.by-
alternately
disconnecting
the
pipes
"t
th"
unions,
that
it is the pump,
and
not
due
to a utoct<aee
in
the
pipe
line.
If with the pipes-disconnected
the
pumps
stfu
work
slufgishly,
the unit
should
be
removed
and
returned
to
Messrs.
E"entltiy
Motors
-(rggt)
Ltd.,
or
one
of their
"special
Retailers"
for
overhaul.

48
TnB
'R'
TypB BBNrrBv.
Fuel
Gauge.
T-rr: $.t
gauge
registers
when
the
master
and ignition
switches
are
rrOn".
As
mentioned
on
page
43,
this
gauge
also registers
the amount
of
oil
in
the
engine
sump,
when
the appropriate
sriitch is
depressed.
The
Ganburetters
(Action).
Two carburetters
of
the
conventional
S.U. type are
fitted
as
sfrown-in.Figs.
13
and
14,
one
being
shown
in
section to illustrate
the principal
parts.
This
lyp.
of
carburetter
automatically
adjusts both
its choke
and
jet
area
in
accordance
with the
demand-of tire
engine as
determined
bv
.th9
degree
of
throttle
opening,
the
engine
spted, and
the load
against
which
the
engine
is
-operating.
Fie.
I3.-CARBURETTERS
lN POSITION
ON
ENGINE.
1. Fuel inlet
and filter,
2. Air
valve
chamber.
3. Hydraulic
piston.
4, Soienoid.
5. ldle Adiustment
screw.
This is
effected
by
using
the
manifold depression
to levitate
a
piston
or
air valve
carrying
a tapered
needle
which
regulates
the
fuel
p-ass_age.
Tfre, uppgr
side
of the piston
is connected by passage
ways
to
the
base
of the piston
facing
the throttle
valves, and
is thus
subject
to the
$epression
in
the
thiottle
body.
As the
air flow
through
the carburetter increases,
so the
depression
b_etwe.en
the
piston
and
the
throttle valve increases, therebytausing
the_piston
to
rise
and
admit
more air, and
consequently
the
needle
to be
withdrawn
from
the
jet,
thus
allowing
inore
fuel
to
flow.
Similarly,
as
thg
air
flow
falla, due to
reduced engine
requirements,
so
the
piston
fallg, maintaining
a
state of
balance wherebythe
piston
keeps
at a
certain height,
dependent on
engine
speed
and
thlottle
opening.
An approximately
constant
air velocity,
and
hence
an

52
Tur
'R'
Tvpr BeNrrBY.
Float
Feed
Mechanisms.
These
are
of
the usual
"top
feed"
pattern,
whereby,
as
the level
of
the
petrol
rises in the
float chamber, a
lever bearing
on the
top
of
the
float
moves
the conical seat
"needle"
upwards
on to its
seating,
so shutting off
the supply.
If
it
is
required to dismantle
the
float chambers, it will
be
more
convenient
to remove
them bodily-after disconnecting
the fuel
pipes,
and the small air
bleed
pipe
to the
cover-by unscrewing
the hexagon
plugs
which secure
each to
their respective carburetter
bodies.
When
the
covers are
removed,
care must
be taken that
the fulcrum
pins
of the
levers
do
not fall out.
They
are normally
retained by
means
of the walls of the
float chambers.
The
chambers should
be
wiped out with
a
piece
of clean wash-
leather before being
refitted.
When
replacing
them,
care must
be
taken
to
see that
the
packing
washers
are in
position,
one
above and
one
below the
boss
which couples each
to
the
carburetter
body.
Furthen Dismantling of
Garbunetter.
It should
never be
necessary
to remove
any other
parts
of
the
carburetter
than
those referred
to in
the foregoing pages.
The
jet
assembly securing nut should not be
disturbed,
as the
refitting
of this requires special tools to
ensure
that the
jet
is
accurately
centralised
relative
to
the
taper
needle valve.
Adiustment of
Gontrols.
There
should be
no necessity for any variation of the
adjustments
as
fixed
by the
makers.
Great care is taken during
the
testing of the
car
to
secure
the best settings, and these should not under normal
circumstances
be altered.
There
are certain
external adjustments,
however,
which are dealt
with in
the following
paragraph.
Setting of
ldling
Adjustments.
r.
Jhe
quantity
of mixture for
slow
running
is determined by
means
of an adjustable screw
on the
front
carburetter
(5,
Fig.
13)
which
limits the closing
movement of the s5rnchronised
throttles.
The
strength
or
quality
of the
mixture
for slow
running
is set
by means
of an adjustable
screw
in
the base of each
carburetter
(11,
Fig.
14).
The screw
operates
to
raise
or
lower
the
jet.
Raising
the
jet
causes the taper
needle
to sink
farther
into the
orifice,
so
weakening the
mixture.
Conversely,
lowering
the
jet
enriches
the
mixture.

Tsn BneKrNG
Sysrnu.
57
CHAPTER
VI
The
Braking
System
General
Description-Possible V
ariations-Adjustments-Adjustment
of Hand
Brake-Adjustment
of Seruo-I.ubrication-Bleei,ing
the
Hydraulic System-Hydrawlic
Master Cylinder.
Generat Description.
The
Bentley four-wheel
braking
system
is
of the
Servo assisted
type,
and comprises a
mechanically driven
servo
motor
of
the dry
disc-brake
type,
which
is
equally effective for
either forward
or
backward
movement
of the
car. Further,
even should
the servo be
out of
action,
the
rod
operated
rear
brakes
are still directly
coupled
to
the
pedal.
Pressure on the
pedal
applies the rear brakes
direct
in
the usual
manner,
and also
engages the servo, but
the front brakes
which are
of
the
hydraulically
operated
type are actuated
entirely by the
servo
acting through the
medium of a balance lever and hydraulic
master
cylinder.
The
servo effect is
distributed between
the front and
rear
brakes,
being
added therefore
to the direct pedal
effect
in
the case of
the
rear brakes.
With the leverages provided,
this results in about
55
per
cent. of the
total braking
being
imposed
on
the front
wheels, which
allows for the
fact that greater
weight is
thrown
upon
the front wheels
during
braking.
The
proportioning
of the servo
pull
to the front and rear brakes
respectively is
effected by a balancing
lever. A separate
equaliser
is
provided
for
the two rea.r
brakes, which,
with the
hydraulic
operation
of
the frqpt
brakes,
ensures
even
braking
on either
side
of
the car.
The
hand
brake
lever
operates the rear brakes
only and uses
the
same linkage
as the foot
pedal.
A diagrammatic
representation
of the whole system is
shown
in
Fig.
17.
A
pull
rod
(1,
Fig. l7), operated by
the
pedal, is
coupled
to a
lever
(2),
on
the servo
motor shaft,
the
motor
itself (3)
being mounted
on the
off-side
of
the
gearbox,
and
driven
at approximately.one-tenth
of
the
propeller
shaft speed.

58
TnB
'R'
Tvpe BBnruBv.
The
lever
(2) has
inclined cams
formed
on the
face of
its boss,
these
cams
engaging,
through
the
medium
of steel
balls, similar cams
formed
on the
boss
of
another lever
(4). From
the latter
a
rod (5)
directly
actuates the
rear brakes
through
the
medium
of the
levers
{6)
and
(7),
which are
pivoted on
a bracket
bolted
to the
"X"
member
of the
frame, and
finally,
through the
rear
equaliser
(8)
mounted
on
a
bracket
suspended
from the
axle.
The
output
from the servo
is
taken
by one
of
the
two
rods (9),
according
to
whether the
car
is moving forwards
or backwards, to
the
lever
(1O). This
lever carries,
in
turn,
a balance
lever
(1 1), the lower
end
of
wtrich
is connected,by
the
rod (12) to
the rear brake
lever (7),
thus
augmenting
the direct
pedal
effort, while
its upper end
is
coupled
to the master
cylinder
(13), which
actuates the
front brakes.
'flic
dashboard
hand brake
(14),
is
mounted
under the
facia board,
convenient
to
the driver's
right hand.
The
ratchet
release is
so
arranged
that
should
it be inadvertently
knocked
or
pressed, the brakes
will not
be
released. In
order to
release the brakes,
the
trigger
must
be
fully
depressed
and held
in
this
position.
The
hand
brake
is
then
pulled,
"rif
"pplying
the
brakes, arid this
action frees
the
ratchet
permitting
the
brakes to
be
released,
provided
that
the trigger
is
still
held.
This
device
is particularly useful
in preventing accidental
release of the
brakes
when
the car
is parked.
To
obtain
this action,
the trigger
is not directly
connected
to the
ratchet
pawl, but
cornpresses
a
spring.
This
spring,
in
turn,
operates
the
pawl, but
is
only strong
enough to
move
it out of engagement
when
the
load has
been removed
by pulling on the
hand brake.
The
hand
brake
is
connected
by an enclosed
cable
(15),to a hori-
zontal lever
(16),
mounted on the
"X"
section
of the
frame which
provides the
required
leverage, and
is
in
turn
coupled
to
the rear
brakes,
through
the levers (7)
and (17)
and
the
rear equaliser.
The
same
rear brake-shoes
are used, therefore,
as for
the
pedal operation,
and the
application and
release of the
hand
brake
can
be
lightened
accordingly
by simultaneous
application
of the
foot brake.
Poseible
Variations.
As
already mentioned, the leverages
are
so
proportioned
that
the
total
braking
effort is distributed
in a
predetermined
ratio between
the front
and
rear brakes.
This
distribution will
be upset if the servo
brakes
are
allowed
to
become badly
out
of
adjustment, or
if
the
seivo,
for any
reason, fails
to
give its correct
output.
A less likely cause
would
be
oil or
grease
on
the brake linings.
The
need for
adjustment of the
rear brakes
will be
indicated
by
excessive travel
of
the hand
brake lever,
whereas
the front
brakes,
which
are
operated
by
the
servo
motor
only,
will
not affect
the hand
brake
or pedal
travel.

6o
Trn
'R'
TypB
BBNrrBy.
It
is
not
necessary
to
jack
up
the
car to adjust
the brakes, as
the
adjusters
are
so
designed
to
give
the correct-shoe
clearances
auto-
matically.
-
If, after
long
service,
the brake
linings
require
renewal,
this will
be apparent
by the
adjusters
coming
to the
eird
of their
travel, and
will
have
a solid
feel quite
distinct
flom
the resistance
felt
when
the
brake
shoes are
correctly
adjusted.
Fig. 18.-FRONT
BRAKE
ADJUSTMENT.
a
1, Adiuster
screw.
2, Hydraulic
pipe.
3. Bleeder
connection.
Fig.
i9.-REAR BRAKE ADJUSTMENT.
. 1. Brake drum..
2. Adiuster screw.
Adjustment
of Hand Brake.
Adjustment
of the rear
brakes
takes up both the
pedal
and
hand
brake
clearance in
the same
operation. No other
adjustment is required.

Tun
BneKrNG
Sysrnu.
Adjustment of
the
Servo.
The
servo
is
of
the
dry disc-brake
type, and
is
shown
in
Fig.
17.
An adjustment
is
provided
for the initial
setting and
wear
of the
friction
surfaces,
but
once correctly
set, should
require
no further
attention for
a considerable
period,
as very little
wear
occurs.
As
the
operation
is
of a
delicate
nature
it is
advised that
this adjustment
should be
effected by
Messrs.
Bentley
Motors
(r9Sr)
Ltd., or
one
of
their
"Special
Retailers".
Lubrication.
The
need for hand lubrication
of various
parts
of the
mechanism
has been reduced
to a minimum,
by
the
use
of selflubricating bearing
bushes
at the fulcrum of
practically
all levers.
The
only
points
that
require attention are
the
jaws
and pins
of the
pull
rods and intermediate
levers
(6, 7
and 17, Fig. 17).
Oil
should be
applied
to these
points
every
5,ooo
miles,
as directed
on
page
3r.
The
ball bearing cams
which
actuate
the servo
(as
described earlier
in
this chapter) are filled with lubricant upon
initial build,
and require
no attention
between overhauls of the chassis.
6r
1.
2.
Fic.
20.-THE
HYDRAULIC
MASTER
CYLINDER
AND RESERVOIR.
Filler
plug.
3. Pin.
Master
cylinder and
reservoir.
4,
Support bracket.
Bleeding
the
Hydraulic System.
Bleeding, that
is
to
say expelling
air from
the system, should
only
be necessary when comÂpletely
recharging the
system with
fluid fol-
lowing the
removal
of
a
component
or
the
disconnection
of a
pipe
joint.
Undernormalcon-
ditions
air
does
not
enter
the system
as a result
of brake application.
To
bleed
the system,
proceed as
follows:-
r.
Attach a clean
rub-
ber
drain
tube to
one
front brake
bleeder
screw
(3,
Fig.
18),
and
immerse the
other
end
in
a clean
glass
j"t
in which
there
is sufficient
hydraulic
brake fluid
to submerge the end
of
the
tube.

64
TnB
'R'
TypB
BpNrrBy.
___. Eor_
topping
up,
the following
procedure
should be adopted:-
With the
control
lever
in
neutral,
the engine should be allowed
to
run
for about
three minutes
before
the
fluid level
is checked.
This
should
be
done
while
the engine
is
still
running.
Fluid
should then
be added
until
the
level
reaches
the
mark
on
the dipstick, taking care
that
the
box
is not
overfull.
Every
zo,ooo miles,
the oil
should be
drained
from
the
gearbox
and
fluid
coupling.
The
drain
plug
on
the
fluid
coupling can-be reached
by remoyitg
the
lower
cover
of
the betl housing (3, Fig.
22),
and
turning
the
engine
by means
of
the starter
motor-until
the
ptug is at
the bottom
position.
The
gearbox
can be
drained
by
the
plug in
the
sump
shown
in 2,
Fig. 22.
After
draining,
both
plugs
should
be replaced.
Fig.
22.-GEARBOX,
UNDERNEATH VIEW.
t. Gearbox
sump.
2.
Drain
plug.
3. Lower bell-housing cover.
4.
Timing inspection
hole cover.
To
refill, first
add
14 pints
of
the recommended
fluid.
With the
lrand
brake
on, start
the
lngine
and let it run for
several minutes.
Then
add
5
or 6 more
pints
of
fluid.
Ailow the
engine to run
for a
short
while and
then check
the
level by
means
of
the dipstick.

Gpansox,
PnopBtr,sn
SneFT AND
Rren
Axrn.
65
Univensal
Joints.
The
propeller
shaft
universal
joints
are fitted with needle roller
bearings,
and each
joint
is
provided
with a
grease-gun
lubricator
(3, Fig.
23),
located
at the centre
of
the
cross-piece.
1. sriding
joint.
z. o,".lt;il;i:L"'fft":::
sHAFr'
Grease nippre universarjoint.
The driven
portion
of
the centre
joint
is provided
with serrations
which
engage similar serrations within
the
propeller
shaft
to
permit
the necessary degree
of
telescoping
movement.
This sliding
joint
is
also lubricated by means
of a
grease-gun
lubricator, shown at (2,
Fig.
23). Every
ro,ooo miles, as directed
on
page
32,
the correct
grease
should be injected
by means of the
grease-gun into all
the
four
lubricators.
Rear
Axle.
The rear axle is
of the
semi-floating type.
The
final
drive
is
by offset
hypoid bevel
gears,
which
possess
the
advantages
of being silent in
running,
and,
owing to the offset
disposition
of
the
pinion,
of enabling a lower
body position
to
be
obtained without
decreasing
the
ground
clearance.
It
i9
important that no other
oil
than that
recontmended
shou,ld be
used
in the rear
axle.
(See
page
28.)
Every
5,ooo
miles, as directed
on
page
3r,
the level
of
the oil
should
be inspected,
and
topped-up if necessary.
Every
za,ooo miles,
as directed
on
page
34,
the casing
must
be
drained,
and refilled
with
fresh oil
to the correct
level.
The drain plug
(2,
Fig.
24)
should be
removed,
with the special
spanner provided,
preferably
when
the casing is warm; and
all
the
oil
allowed
to
drain out.

SrBonrNC,
SuOCx
Deupcns, ROap
SrRlNcs,
WnBnrs
eNn
TvnnS.
67
CHAPTER VIII
Steering,
Shock
Dampers,
Road
Springs,
Wheels
and Tyres
Steering
Box
and Column-Steering-Front
Suspension-Warning,
Front Swspension,
Springs-Steering
Arms and
Joints-Front
Stabiliser
-Rear
Hydraulic
Shock Dampers-Rear
Road
Springs-Wheels-
Wheel
Discs-Lwbrication
rf Wheel
Bearings-Tyres-The
Jacking
System-Wheel
Changing-Fitting
and
Removing Tyres-Inf'ation
of
Tyres-Balancing
Road, Wheels.
Steering
Box and Column.
The
steering
mechanism is of the
cam-and-roller
type, and requires
no attention
beyond
inspection
of the
oil
level.
The
cover of
the
box is
provided with
a filling
plug (2, Fig. 25).
Every
5,ooo
miles, as
directed
on page
3r,
this
plug should
be
removed,
preferably
when the box is warm,
and the
level of the oil inspected.
If
necessary,
oil
should be
poured
in until
it is on the
point
of
over-
flowing
from
the
plug
orifice.
F'or
correct oils,
see
page
zB.
1.
2.
3,
Steering
column.
Oil
filler
plug.
Gear
change
contrqf.
Fie. ZS.-STEERING
COLUMN.
4. Micro-switch.
5. Reverse light switch.

6B Tsn
'R'
TvpB
BrNrr.Bv.
Steering.
Experience
has shown
that
too
much importance cannot
be
attached to
proper
balance
of
the
front
wheels
and tyres.
As it is only
possible
to
balance the
wheels
and tyres statically,
this
does
not
eliminate the effect of slight
out-of-balance forces which
can only be
detected dynamically. Such a
condition
may
be
caused
by
the
normal
wear of the tyres on the
front
wheels; as
is inevitable
*itn
independent
front su,sfension, tyre wear
will be slightly less
regular than on the rear wheels.
Therefore, it is recommended
that
the front wheels should
be
periodically
changed
to the
rear
and vice versa to
even out the wear
of
the tyres.
Front Suspension.
Each wheel is indeperldently
sprung,
the
suspension consisting
of the two upper
and two lower radius arms
of different
lengths
set
at a leading
angle, between
which a vertical
yoke
is
carried,
and
on
this
the
stub
axles are pivoted.
The
upper radius
arms are
connected to and operate the special
Bentley
shock
damper,
which
eff ectively dampens excessive
spring
action.
The main helical
coil spring
is
mounted between
the
forward
lower
radius
arm and a
seat formed as an integral part of the chassis frame.
The
ball
joints
and
the
steering
pivot
bearings are lubri-
cated
from
the
central
chassis
system.
(See
Fig. 5.)
The
shock
damper
consists of
two
pistons
operatingin
cylinders
full of oil, the
oil being
dis-
placed from
one cylinder to the
other
through
drilled
passages,
the degree
of damping being
controlled
by spring - loaded
valves.
'
Until
it is obvious
that the
eflectiveness of
the
shock damper
has
become
reduced,
or undue
leakage
is apparent, no attention
whatever will
be necessary
for
ro,ooo miles, when the level of
the oil
in
the
shock
damper
should
be
inspected,
as directed
on
page
32.
It
is of vital
importance
that
only
perfectly clean
oil
of the
correct
grade
should be
used, and
Iine
gauze
before
using.
Fig.
26.-FRONT
SHOCK
DAMPER.
1. Shock
Damper.
2. Filler
Plug.
3. Hydraulic
Brake Pipe,
this
should
be strained through a

StnBRrNc,
Suocx
Deuprns,
RoAn SrnlNcs,
Wsnrrs
eNo Tvnrs.
69
Straining
is facilitated
if the oil
be first warmed to
about
75"C.
The
importance of the
above cannot
be
over-emphasised, as a
very
small
particle of
foreign matter
in
the
oil
may lodge under one of the
valves and
impair
the
effectiveness
of the shock
damper.
WARNING.
Front Suspension
Springs.
No
attempt
must
be
made
to remove the coil
springs
of the
front
suspenslon.
Special appliances are
required because the
powerful
springs
are
compressed
even
when
in
the
rebound
position.
Any
necessary
dismantling
or
adjustment of the suspension
must
be
effected
by
Messrs.
Bentley Motors
(rgEr) Ltd., or one
of
their
"Special
Retailers".
(See page 16.)
Steering
Arms and
Joints,
The steering
gear
should
be examined occasionally to see
that
all bolts are
tight and
joints
well lubricated.
If
any
of the nuts are found loose,
and only
retained by
their
split
pins,
the
latter
should
be
removed,
the
nuts
screwed
up
tightly
and
new split
pins
fitted.
The
ball
joints
of the cross
and
side
steering tubes are
lubricated
from the
centralised
chassis
system,
as
illustrated in
Fig. 5.
The
bearing
pads of all
joints
are
spring-loaded,
being self-adjusting
for wear. They
should
not
normally
require
attention
except
when
the
car
is
undergoing
a
general'overhaul.
Front Stabiliser.
In
order
to
check
any tendency of the car
to
"rol1"
on
corners,
a steel torsion-rod stabiliser
is provided at
the
front end of the
chassis.
The stabiliser
is
carried
in rubber bearings, and
is
coupled to
the
wheel
mountings
by links
with
rubber pads.
No attention
is necessary.
-
Rear
Hydraulic
Shock
Dampers.
Hydraulic shock dampers
of Bentley design
and
manufacture
are fitted to the
rear
axle, one
of the dampers
being
shown
in
Fig.27.
Unless
it is
obvious that
the effectiveness of the shock
damper
has
become reduced, or undue
leakage of
oil
is apparent,
no attention
will
be necessary for
ro,ooo
miles of
running.
After ro,ooo
miles,
it is
necessary to
inspect
the
oil level
in
the
shock dampers as
directed
on
page
32.

SrnrnrXC,
SttocK
DaMpens,
ROlo Srntncs,
WnBnrs
aNo TvnES.
7I
The
plug
(1)
can then be
removed
with a box-spanner,
and
the
oil
level-restored,
if
necessary, to the
bottom
of
the
plug hole,
the
oil
being
poured in very
slowly to
avoid entrapping
bubbles
of air.
It
will
be
-found
most
convenient
to
add
oil by
means
of small
syringe
provided
in the tool
kit. When
replacing the
plug, care
must be
taken
that
its
washer
is
in
position.
The
shock damper
consists
of a piston assembly
operating in a
cylinder
which
is
maintained
full
of oil, the
latter being displaced
fiom one
end
of
the
cylinder
to the
other, past spring-loaded
valves.
The
loading
of these valves,
and
hence the degree
of damping,
is
controllable
through
the
rJRide
Control"
lever by
means of
a
small
pump carried in a
casing
bolted to
the
gearbox,
which
maintains
a
pressure
of oil in a
system of
piping. This
pressure
is
variable,
and
is
cohtrolled
through
a relief valve,
operated
by the aforementioned
lever.
The
pump
is charged with
oil
from the
gearbox. It must be
observed
that
oil
is not actually
pumped into
the dampers,
and
there
should be
no wastage
of
oil from the
pump
unit
or pipe
line.
Such
wastage
or
leakage
will
impair the
functioning
of the
control.
As it
is of such
importance
that
the
shock dampers,
and also the
pump
and
pipe line,
should be
maintained
full of oil, evidence
of
undue
leakage
should
be
at
once reported
to
Messrs. Bentley
Motors
(rqSr) Ltd.,
or one of their
"Special
Retailers".
(See page 16.)
Rear
Road
Spnings.
The
forward ends
of
the
rear springs
are
pivoted
to
the
frame by
means of
steel bushes.
The
shackle
pins
at the
front and
rear
ends
are
of the
threaded
type,
and
both bushes
and shackle
pins are
lubricated
from the
centralised
chassis system.
The
advantage
of threaded
bearing
pins is
that
they do
not
develop
end-play
as the
result
of wear.
The
springs
themselves
are encased
in leather
gaiters
and,
b5r
means
of a special
arrangement
of oil holes and
grooves
in the
leaves,
the ends
of
the
three
longest leaves
of each
spring
are
lubricated
by
surplus
oil
from
the
eye
of
the
master
leaf.
Owing
to this
arrangement,
in
combination
with absorbent
material
inside the
gaiter,
the
springs
are entirely
self-lubricating
and remain
free from squeaks.
Wheels.
All wheels are
of
heavy
gauge
pressed steel,
with
16"
by
5"
well-base
rims, and
are
secured
with five
nuts.
The securing nuts
for the
"off-side" or
R.H. wheels
have right-
hand
threads,
and
those
for
the
"near-side" or
L.H. have
left-hand
threads.
The
nuts must be tightened,
with
the wheel-brace
provided,
rlvenly
and securely,
and the threads
must be
kept clean and
greased.

Srrrnrwc,
Sttocx
DaupBns,
RoAn
Srnlltcs,
WHrBrs
eNn
TvnEs.
73
Fie.
28.-FITTING JACK
TO
SLIDE. Fie. 29.*OPERATING
JACK.
Wheel Changing,
No
difficulty
should be experienced
in wheel changing;
the
spare
wheel
can be
put on the rear or front hub
with rzery
little effort
as
follows:-
Rean.-Having
jacked
up the car,
applied
the
hand
brake
and
removed the
rear wheel:-
r.
Roll the spare
wheel
under the
hub, the top of
the wheel
being
inclined outwards, then
with a foot at the
bottom
of the
wheel,
lift
by
the
rim
on to the
hub
extension,
as
shown
in
Fig.
30.
2. One
of the five wheel studs will
be found to
be nearly
on the
horizontal halfway line, either
to
the
front or
rear. Rotate
and
tilt the wheel
until
this stud
probudes
through
the
nearest
stud hole.
Fig.
3O.-MOUNTING
REAR
WHEEL.
Fie. 31.-POSITIONING
REAR
WHEEL.

SrnrnrNc,
Snocr
Deuprns,
RoAo SnntNGs, Wnnnrs
exo
Tynrs.
77
(ii) If a hub on a bench
is not available, make
sure
that the
front hub on the car is
quite
free to
rotate and not restricted
by
too close
adjustment of
the
brakes.
(iii)
Remove
all balance weights, bolts
and nuts.
(iv)
Reverse
the
bolts
in
the wheel, this
will
allow
the operation
of balancing to be
performed
more
easily, as the balance
weights may then
be fitted externally.
(")
Refit the wheel to the
hub. Allow to swing
and
note
the
tight
point.
Put
one
weight here.
Allow the wheel
to
swing
again.
If the wheel
is in balance, space
the other 3 weights
evenly round the wheel.
("i) If the light
point
is unchanged
in
position, add a second
weight,
using one
of
the
adjacent
holes. If
this corrects
the balance,
add
the other z
weights
opposite
each other.
1.
2
Fig.
35.-SECTION
OF
Well
base rim.
Wheel
disc.
REAR HUB
AND WHEEL.
3. Wheel securing nut.
4. Balance weight.

?8
THE
'R'
Tvpr BBNrtBv.
(vii) If
z
weights together are too much,
try
moving
them away
from
each other.
Go
one
hole
at a time and move each
weight alternately.
When
balance
has been achieved
add
the z weights opposite each other.
(viii) If
z
weights together are insufficient,
add a
third,
using
an adjacent
hole.
If this balances
the wheel,
remove the
centre
weight and refit it 4 holes to one side. Fit
the
4th
weight
4
holes to the
other side.
(i") If
3
weights are insufficient,
add the
4th,
and if this is too
much, start separating
the outer
z
weights as in (vi) above.
(")
Remove
the
wheel and reverse the
bolts so as to return
the
balance
weights
to their correct
position, on the inside of
the wheel.
("i) Refit
the wheel and
the
wheel
disc
assembly.
The
correct
tension
on
the disc is attained by
giving
the
nut one com-
plete
turn, with
the
special
spanner
provided, after
the disc
has
been felt
to
be
in contact with the
rubber stops on
the
wheel centre.

EncrNB
CoorrNc SysrBna.
79
CHAPTBR
IX
Engine
Cooling System
Coolant-Coolant
Pump
and,
Fan-Fan
Belt Adjwstment-Oaerheating
-Engine
Thermostat-Radiator
Mounting-Frost
and Anti-freeze
Mixtures-Car
Heater.
Goolant.
The cooling system
is filled
with a
zS
per
cent. mixture
of inhibited
ethylene
glycol
and water
before
the
chassis leaves
the
factory,
and it
is strongly
recommended
that
this,
or a similar
anti-freeze
mixture,
is
used
all
the
year
round,
both summer
and winter.
The
purpose
of
this is not
only to provide protection
against
frost
during the
cold
weather,
but also to prevent
any corrosion of
the
coolant
passages
and subsequent
deterioration
in
the
standard
of
cooling,
If
there is
any abnormal loss
of coolant,
the cause should
be
ascer-
tained and rectified,
and
the system topped
up with
the correct
anti-freeze
mixture
to
maintain
the
level
to
the bottom
edge
of
the
filling
orifice.
If
either of
the
recommended
compounds (see page
Bz) are
not
available,
plain,
preferably
soft, water
may
be
used
when there is
no
danger of
frost.
The radiator filler
is
located
under the
left-hand
side of
the bonnet.
A
warning notice is
embossed on
the
cap
to
the
effect
that it
must
not
be
removed
when the engine
is
running.
Hot
coolant
is likely
to
be
forced out in
such
circumstances.
A drain
tap
is
situated on
the
pipe connecting
the pump
with
the
bottom
of
the
radiator.
It is in the
"off"'position
when
the handle
is
pointing
downwards.
On
no account
must
any
strong
alhaline
compound
be wsed
to clean
out
the
coolant system.
Seaeral
swch
compounds
are aaailable,
but
their
use
must be
carefully
auoided, owing
to theiact that they
haae a
d.etrimental
chcmical,
action on
al,uminium.
It
is very
important
that a glycerine.base
compound
should
not be
mixed
with
a
glycol
base
compound,.

ExcrNB CoorrNc
Svsrnu.
8r
(c) There
may
be a shortage
of coolant
in the
system.
(d) Detonation
and
poor
grade
of
fuel.
(.) Radiator
matrix
blocked
with flies
or dirt,
etc.
Engino
Thermostat.
The
thermostat
which
controls
the
flow through
the
radiator
to
suit
the
engine
cooling
requirements
is
contained
within
a casing
(6,
Fig.
37).
It
is
arranged
to
maintain
a minimum
coolant temperature
of
approximately
78"C.
Reference
to
the
instrument-board
thermometer
will
indicate
that
the thermostat
is operating
correctly
and that
there
is no shortage
of coolant.
An
unusually
and
consistently
low
temperature,
after the engine
has
been
well
warmed
up,
indicates
failure
of the thermostat.
A
by*pass
pipe acts to short
circuit
the
radiator when the
thermoslal
valve
is
closed
or only
partly open. This
arrangement
ensures
a
quick supply
of
heat to
the
induction
pipes a-fter
sta_rting
from
cold
as
well
as a
rapid warming
up of the engine
coolant
jacket.
Radiator
Mounting.
The
radiator
comprises
two
main
units, namely, the
outer shell
and
the
matrix
itself, the
complete
assembly
being
mounted
on a single
central
rubber
support.
The
shell
is
diagonally
braced
and
is bolted
to the
wings
and
valance
plates.
The
radiator
matrix
is
secured
in
the
shell
at
tfiree
points, which
are arranged
to
proVide freedom
for
expansion
under
heat.
The
object
of
this special
construction
is to avoid sidewaVf move-
ment
of
the
radiator
assembly
due to
road shocks,
and to
isolate
the
matrix
from such
shocks.
No
lubrication
or
attention
is necessary
in
connection
with
the
mounting.
Frost
and
Anti-Freeze
Mixtures.
As
long
as
the original coolant
is
maintained
in
the
system,
no
precautions
need
be taken
against frost.
If, for
any
reason,
the original
coolant has
been replaced with
water,
then the
system
must
be drained
if
the
car
is
to
be
left
exposed
to
temperatures
below
3zo
F

8z
TnB
'R'
Tvpe
BBurrrY.
Fig.
38.-CYLINDER
JACKET
DRAIN TAP.
1,
Drain tap.
Draining
is accomplished
by
opening
three
drain
taps,
one
situated
on
the
pump
inlet
pipe,
one
on the
right-hand
side
of
the
cylinder
block,
(1
,
Fig.
38),
a1d
one
on
the
car
heater
return
pipe.
The
filler
cap
must
also be
released
a
few
turns.
Also, before
attemPting
to
turn
the
crankshaft
for starting
after
exposure
to
frost,
hot
water
showld,
be
poured,
ouer
the
coolant
fwmf
to
thaw any
particles.
of
ice whiCh
may
be
present
in
the
casing,
and which
would
probably damage
the
impeller.
A
suitable
anti-freeze
mixture
is
made
by
mixing soft
water
with
either
Inhibited
Ethylene
Glycol
or
"Bluecol",
in
pro-
porfions
dependent
on the degree
of
frost
likely to
be encountered.
The following table
gives
an
approximate
indication
of the
amount
of frost
protection
ensured by different
strengths
of
mixture.
Freezing
point
Degrees of frost
r,z"
F.
zo"
F.
2"
F.
300
F.
ro
pts.
ro
pts.
-30
F.
35"
F.
r.
Inhibited
z.
"Bluecol"
Ethvlene Glvcol
...
6f
pts.
6f
pts.
rr
pts.
rr
pts.
When
changing from
water
to anti-freeze,
the
radiator
system
must
be drained. New
anti-freeze oI
the
required
amount
should
be
mixed
with
an equal quantity
of soft water
before
being
poured
into the
radiator, the radiator being
finally topped
up
with
soft water.
The
engine should then
be run until
normal
operating
temperature
is reached,
to ensure uniform distribution
of
the
anti-freeze
throughout
the system.
The
rubber connections must
be
carefully
examined
and
replaced
if trnsound,
as any
leakage
will
necessitate
replenishment
with
anti-
I
reez-e mixture.
\il
hen using
an anti-f reeze
mixture
as
described,
a similar
mixture
should
be used for topping-up
purposes
Gan Heaten.
A
hot
water
heater
is
warm
air being
circulated
the
heater.
fitted under
the
front
Passenger's
bv
an electric
fan which
is integral
seat,
with

THe ErncrRrcAl
Sysrru.
85
CHAPTER
X
The
Electrical
System
G
ener
al-Dynamo-F
us e B
o
x-O wtpwt Regul,ator
and
C wt-Oi
ut-switch-
b o x- A mm et er
-B
att er
y
-F
ir
st C h ar g
e-T o
p
p
i ng-
U
p
-
S p e cif.c
G:r au ity
of
Electrol,yte-charging-charging-
BatteVy
fVoni
owisid,i
so%rce-
M ai nt en
qn
c e-1.
gniti
o
n- I
gniti
o n- C o iI-
I
gniti o n T
imi ng-F
ir i ng o r
d er
of
Cylinders-Sparking
Pl,ugs-starter
Motor-starter
Motor
Suitch-
Micro-Switch-Use
of Starter
Motor-Electric
Fuel,
Pumps
and Gauge-
Electric Horns-De-misting
Eqwipment-Electrical
Fiwk
Locati1n-
Recornmended
L!*!
BwIbs-H
eadlamps-Replacing
a H eadlamp
Butb-
Aligning_the leadlamps-The
side- Lamps-Radio-To
sei up
the
Tuning
Push Bwttons.
General.
The equipment
comprises_a
dynamo,
fuse
box,
automatic
output
regulator
a_nd
cut-out,
switchbox,
ammeter,
a
rz-volt,
approximately
ss-amperq-h9ur
battery, a
starter
motor
with
relay-opeiated
switch,
two
electric
horns
with push-button
switch
at head
of
steering
column,
!ead,
side,
rear
and interior
lights,
windscreen
wiper,
trlfficators,
de-froster,
de-mister,
car heater,
radio,
electric
fuel pumps
and
gauge,
and battery
ignition,
consisting
of coil
with
com-bined
low-t6nsiin
contact
breaker
and
high-tension
distributor,
and
the
necessary
wiring.
Incorporated
in
the
distributor is a governor,
which
effects
automatic
control
of
the ignition
timing.
The wiring
diagram
(Fig.
40),
shows
the units
urith
their
electrical
connectiorp,
the various
wires being
indicated
in
colours
to
correspond
with
those
of
their actual
coverings.
The
electrical
system is-earthe4
or.
the
positive
side
of the
battery
to the
chassis
frame,
and
all
switching is
done
in
the negative
leads.
-
Before
doing any
work
on a chassis
which is
likely
to involve
the
electrical
system, it is
advisable
to remove
the
chassis
fiame
connection
f.]roq
the p-ositive
battery
terminal,
and
so
render
the
whole
system
9ead,
but
do not
disconnect
whilst
any
charge
or
discharge
current
is passing.

THn ETBCTRTcAL
SysrBnr. 87
Messrs.
Bentley Motors
(t93t)
Ltd., or one of their
"Special
Retailers".
Emphasis
is
laid
on
this
point,
as cases have arisen of faulty
operation
of the dynamo,
due to
inexpert
fitting
of brushes.
When
it
is necessary
to disconnect
the wires to the
dynamo, care
must be
taken
to ensure their
correct
replacement.
Fuse Box.
The
large
fuse
box
(2, Fig. 42)
carries
the
circuit
{uses. Each
circuit
fuse
is
one strand of
No.
3z
S.W.G. tinned copper
wire.
The small
fuse box
(1
)
carries
the main
fuse; this is
three
strands
of No.
Sz
S.W.G. tinned copper
wire.
Spare
fuse
wire
of
this
gauge
is
provided
in
a special holder within
the
large fuse
box.
Special care must
their holders,
and that
Output Regulator
and Gut-Out.
The output
regulator
and cut-out
are mounted on the front
of the
dashboard,
and are shown
(5,
Fig.
a2).
The
output
regulator
operates
to
control
the
dynamo
output
by
varying
the field
excitation
in
accordance with the load on
the
battery
and
its
state of
charge.
The
operation
of
the regulator
depends upon
the fact
that the
voltage
of a battery
varies between certain
fixed limits
according
to
the
state of charge
of the battery,
the voltage being,
of
course,
a
maximum
when the battery is
fully charged,
and a
minimum
when the
battery is fully
discharged.
The regulator
is combined
structurally
with
the cut-out.
The
regulator
and cut-out
are,
however,
electrically separate, employing
separate
armatures,
though
they possess field
systems which are
common
over
a portion
of
the
magnetic
path.
The cut-out
is operated
when
the
dynamo
speed rises high
enough
for
the
dynamo
to
charge
the battery by means of its
shunt
coil
connected
across
the main
terminals
of
the
dynamo. This closes
the cut-out
contacts
and so connects
the
dynamo with the battery,
via
thp regulator
and ammeter,
as
shown in
the wiring
diagram
Fig.
ao).
The series coil
is so connected
that, when carrying
the
charging
current,
it
assists
the
shunt coil
in holding
the
contacts firmly
together.
When
the
dynamo
slows
down, and
its
voltage
falls
below
that of
the
battery,
the current
reverses
through
the
seri"es coil,
and the effect
of
the shunt
wrnding
becomes neutralised,
which results
in
the
contacts
falling
apart.
be taken that
all
fuses
are
gripped
firmly
in
the contacts
are clean and
bright.

B8
Tsn
'R'
TypB BBxrunv.
Fis, 42.-F!JSE
BOX, OUTPUT
REGULATOR
AND
CUT'OUT.
Main
fuse
box.
3. Cover,
fuse
box.
5. Output
regulator
and
cut-out.
Circuit fuse box.
4.
Joint
box.
6.
Spare
fuse
wire holder.
The output
regulator
and
cut-out
requires
no
attention;
it is a
sealed
unit,
and no
adjustment
of any kind
must
be attempted.
If any
defects
in operation
should
develop, as
described
under
"Electrical
Fault
Localion"
(p"g.
98),
which are traceable
to
the
regulator,
it
must
be
detached
bodily and
returned, uith the
seel
unbroken,
to
Messrs.
Bentley Motors
(tggt) Ltd. or one of their
"Special
Retailers",
for
correction.

Tnn
ErrcrRrcAl
Sysrru.
89
Switchbox,
Mounted on the instrument panel,
this
unit
includes:-
(a)
Master
switch and lamp
switch
combined.
(b)
Ignition
switch.
(c)
Push-button switch for
the starter
motor.
(d)
A
lock which
can be locked
and the key
withdrawn
either:-
r.
When the
master
switch is in
the
rlOfftt
position;
or,
z.
When
the
master
switch is in
the
r(P.L."
(parking
lights)
position.
No
attempt
must be
made
to lock
the
switch in
other
positions.
With
the
master
switch in
the
rrOfitt
position,
all
accessories
and
liglrting circuits,
with the
exception
of
the
roof
lamp,
are rendered
inoperative.
l\{ovement
of this
master
switch
to
the
rrOnt,
position
renders these accessories
available.
The
various
combinations
controlled
are
clearlv
indicated,
as
follows:-
Ofr.-All
circuits
off
except
for
roof
lamp.
On.-Accessories
available.
S. and T,-Side
and tail
lamps
on and
accessories available"
H.,
S. and
T.-Head,
side and
tail lamps on
and accessories
available.
P,L.-((Parl<ing
Lights", side,
tail and roof lamps
on. (No reading
is
shown on
the
ammeter
and all
other accessories are
"off
".)
A
separate switch is provided
for
the
ignition,
marked
trOnt'
and
t'Off".
Normally,
this switch can be
left
in
the
ttOnt'
position,
and
the
switching to
start the engine
can be
carried out on the
master
switch.
No independent
charge
position
is
provided
owing
to the
presence
of
the output regulator.
Whenever the
master
switch
is
on, connections
are
made
which
cause
the dynamo
to charge
the
battery
through
the
regulator,
as
previously
described.
Operation
of
the
push-button
switch for the starter
motor
completes
a
relay
circuit,
which
in
turn
causes the main
starter switch to
close.
Amm'eter.
The ammeter
is
an
instrument
with
a central zero
and
3o-ampere
range,
a
needle deflection indicating
Charge
or Discharge.
As
already explained
]rnder
"Outpu!
Iegulator",
th9 charge
rate
varies
in accordance
with the
state
of the battery.
Consequently,
no
alarm
need
be felt
if
the
charge
indicated
on the ammeter
is quite
small,
especially
after a considerable
period
of running with no
extra
consuming
apparatus,
such
as
lamps,
in
use.

9o
TsB
'R'
TypB Bnrqrrpv.
This
will probably
indicate
that the battery is well charged.
Under
these circumstances,
switching
on
the
headlamps may
cause
a
discharge reading
to
be
shown,
but this
will
only occur
ior
a
short
time,
as
the
dynamo will
quickly respond
to the slightest
drop in
battery
voltage,
due
to the
discharge, and re-adjust
the output
accordingly.
An
unnoticed
reversal
of
the ammeter connections
causes
the
charge
and
discharge indications
to be
reversed.
Battery.
The battery recommended
and specified for
this car, is
as follows:-
Battery Maker's
Type Designation.
Normal
Charging
Current.
P. & R.
Dagenite.
Exide.
6
H,ZP7-S
6 MXP9-R
5
amperes.
The full
title should
be
given
when
ordering
a replacement
battery
or spare
parts.
First
Charge.
If the battery.
i,s
received
in
a
dry
condition,
it
will
be
necessary
to
fill
the cells
with
acid
solution
of
the
correct
specific
gravity
and
charge
the battery,
before
it
is put
into
use.
In such
cases,
it is
strongly
recommended
that
the
necessary
charging
should
be undertaken
by
. properly
equipped
service station,
as
urilesi
the
initial
charge
is correct
the
battbry
will
never give
satisfactory
servtce.
Topping-Up.
.
In
the majority
of
cases,
however,
the
battery
will have
already
been
charged
and
the cells
filled
with
acid
solution.
Under normal
op.erating
conditions
the level
of
the
solution
will
gradually
fall in
each
cell, mainly
owing
to- evaporation
losses.
A regular
inspection
should
be
made,
as
directed
on
page
3o,
to
see
thai the
level of
the
acid.
solution
has not
fallen
to
such
an
extent
that the
tops of
the separators
and plates
are
exposed.
I1 this case,
the battery
should
be
"topped-up",
by removing
the
vent'Pl"g.in
the centre
of
each
cetl
lid
^"ita
utiaing"distilled
water
to each cell;
until
the level
of
the
solution is
approximately
f-"
above
the
tops of
the
separators.
It is
difficult.to-lay
down
a
hard
and fast
rule
as
to
how frequently
"topping-up"
qilt
.be.required,
because
this
varies
so
much,
according
to the
use
to which
the car
is
put,
and also
the temperature
in
whic6
it operates.
It must
be
remembered
that
"topiing-up"
will
be
necessary more
frequently
in
hot
weather
than in Cold.
- -

TnB
ErBcrRrcAL
SYsrru.
Normally
it
should never
be
necessary
to add sulphuric
acid
to the
cells,
unless
it is
definitely
known
that
some
of
the
acid has
been
lost
owing
to
slopping or spilling.
The addition
of
acid
to
the battery
should
only
be done
by an experienced
battery
man,
who
at the
same
time
will
carry
out any adjustments to
the acid
gravity.
Specific
Gravity of
Electrolyte.
Various
acid specific
gravity
figures are
given
for
reference in
the
following table,
and
they
apply to both makes of
batteries.
Acid
gravity
figures are
taken by
means
of
an hydrometer.
Specific
Gravity
of
Sulphuric Acid
Solution.
(Corrected
to
7o'
F.).
9r
Filling
in
for
First
Charge.
F ully
Charged.
Climate.
Temperate
Tropical
(i.".
where the
temperature is frequently
9oo
F. or over).
6 HZP1-S
6 MXP9R
r.z6o
r.r90
t.z8o
(r.z7o-r.285\
T.2TO
(t.zoo-r.zr5)
Charg ing.
The
output of the dynamo
on
the
car is controlled
so as to vary
with
the state
of charge
of
the
battery.
Overcharging
the
battery is
thus
automatically
avoided. The dynamo will, under
ordinary running
conditions,
provide
enough
current to ensure
re-charging of
the
battery,
but
in special cases,
e.9.,
when the
car is frequently standing with the
lights
on
and daylight
running
is of short
duration,
it
may
be
necessary
to take
the
battery off the car
from
time to time
for a
bench
re-charge.
This re-charge
can be done
by any well-equipped service
station.
-
Ghanging Battery
from an
outside
source,
It is possible
to
charge the
battery from a trickle
charger
whilst
in position on
the
car,
making
use of a
flexible lead and the special
two-pin
plug supplied,
which
fits
the
charging
plug
socket on the facia
board
arranged
just
above the
steering column.
Be certain that the direction
of
current
is correct, the socket
holes
are marked * and
respectively, and,
in
addition,
are
made
of
different
sizes
in
order to
clearly
distinguish
them.

TnB
'R'
TvpB BrNrrny.
Maintenanco.
The
battery must be
well
secured in its box so
that
it
cannot
move.
The cable terminals should be well coated
with lanolin
or
pure
vaseline (not
grease),
before putting
the battery
into
service.
The top of the battery
should always
be kept
clean,
and as
far
as
possible,
dry; attention
should be
given immediately to the
least sign
of
corrosion occurring on
the terminals.
Keep the terminals and
connectors
well covered
with
lanolin or
pure
vaseline,
all
contact surfaces clean and firmly screwed
op, but do
not
use abrasives for
cleaning.
To
remove corrosion,
use a
solution
of
ammonium
carbonate,
applying with a
rag.
Do
not inspect
the battery with the
aid of
a naked
light, and on
no account disconnect
anv of
the
batterv terminals
or connections
when a charge
or dischar["
"urr.nt
is
passing.
The battery
must
never
be allowed to
remain
in
a discharged
condition. A battery not in
service should
be kept
in condition by
fully
charging
it and
then
giving
it a freshening
charge at
least once
every two months.
It
should
be given a thorough
charge
before being
put back into
service.
Care should be taken
to avoid an
inadvertent
discharge
of the
battery.
Such a discharge
may
occur
if
there
is
an earth
in the
wiring
system,
instruments
or
fittings,
or
if
the
ignition
switch
be left on
in
error, and the engine
happens
to come to
rest
with the
low-tension
contacts
in
engagement.
Provision is
made
for
the latter
contingency
by
the
red
warning
lamp,
which rvill
remain
illuminated
until the
ignition
switch is
turned off.
It should be
made
a practice,
when leaving
the
car,
always to
observe
that
the warning
lamp
is not illuminated,
and no switches
are
left on, and
that no
discharge
is
shown
on
the ammeter.
lgnition.
The
battery
ignition
contact breaker and
distributor
are shown
in
Fig.43, an internal
view
of
the contact
breaker
being
given
in
Fig.
44.
A
condenser (4,
Fig.
aB)
is connected
across
the
contact
points.
In setting the points,
the
gap
opening
should
be .or9"
(.+8g
m/m.)
to
.o2r'(.SSS
m/m.), adjustment
being effected
byloosening
the
locking
screws
(3
and 4,
Fig.
44) and turning
the
adjusting
screws
(5
and 6)
to
obtain the
correct gaps,
measured
with
a
feeler
gauge.
Make
sure
that the locking
screws
are
correctly tightened
aftef
adjustment.
The
screws
(7
and
8)
must
not
be disturbed,
as this
would
upset
the
synchronism
of
the two
contact
breaker
arrns.
Every
5,ooo
miles, as
directed
on
page
3r,
the
rocker
arm
pirrgt
pins
(9
and 1O)
should
be
lubricated
with one
or
two drops
of
'oil
"4";
at
the
same time
apply
one
or two
drops
of
oil
"8" to
the
cam
lubri-
cator
pad.
Also remove
the
rotor
and
apply
a
few
drops
of
oil
"A"
to
the
felt
wick (12),
to lubricate
the automatic
timing conhol.

TnB
ErBcrRrcAL
SvsrEM.
93
The
lubricator
(3,
Fig.
43;
should be
given a turn
every rrooo miles, and
when
empty,
refilled with
the
correct
grease,
as specified
on
page
28.
The
rotor
incorporates a
small
carbon
resistance
sup-
pressor,
to
comply with
reg-
ulations
governing
telcvision
interference.
The
high-tension
distrib-
utor
requires no
attention
beyond an occasional
rviping
of
the
interior and
exterior
with
a clean, dry
rag.
lgnition Coil.
The
high-tension
ignition
coil
is mounted
on
the,front
of
the
engine,
as
illustrated
in
Fig.
45.
Connected
to
the
terminal
marked S.W.
(switch
wire)
is a
r mfd. condenser
to
reduce
electrical
interference
to
the
radio from the
ignition
system.
Care
must be taken
that
in
the
event
of a replace-
ment
coil being
fitted, that
the
condenser
is
correctly
connected
to the terminal
marked S.W.
and
not
to the output (C.8.)
terminal
of
the
coil.
The
outside
of
the
coil
casing should
be
kept clean;
misfiring is
occasionally caused
by an accumulation
of
dirt
around the terminals.
lgnition Timing.
If the
ignition
timing has been
deranged, it
can be
reset by reference
to
the
markings
on
the engine flywheel.
To
carry out
this
operation,
the crankshaft should
be rotated until
the
mark
'rlGN.
TDC.''
on
the flywheel registers urith the
small
pointer
_attached
to the
lower
bell-housing cover,
'when
No. r
piston
is
at
thb top
of its
firing stroke.
The
car
should be run up on a
ramp
or over
a
pit.
Examination
of
the lower
bell-housing cover (3,
Fig. 22)
will show the
small inspection
hole
on the side.
The
preferable method
is
to note
the
position
of the
pointer
and
then
to remove the cover.
Operate
the starter
motor
to
approximately
line up
the
flywheel marking;
replace
the cover for a temporary
check.
Remove
the cov_er an{
prise
the flywheel
round into correct
position,
then permanently
replace
the cover.
Fts.
43.-IONTACT BREAKER
AND DISTRIBUTOR.
1. Distributor.
4.
Condensen
2.
Contact breaker
5. Spare condenser
3. Lubricator.

94
Tue
'R'
TvpB BBurrBv.
Another
method is
to
use the
starting
handle to turn
the en-
gine,
which
obviates the
need for
removing the
bell-housing
cover. It
must be
remembered
that
the
starting
handle
operates
through the
friction
damped
spring
drive
unit,
and
there-
fore
allowance
must
be
made
for
the wind-up
of
the
spring drive unit.
If
it is
decided
to use
this
method,
the timing
should
be set .3oo"
late
of the
lGN.
TDC.
Fie. 44.-INTERIOR
OF
CONTACT
BREAKER.
1 and
2.
Rocker
Arms.
7
and 8.
Synchronising Adjustment.
3 and 4. Locking
Screws.
9 and 10.
Pivot Pins.
5
and 6.
Adjusting
Screws.
11. Cam.
12. Felt
Wick.
mark
on
the
periphery
of
the
flywheel.
The contact
breaker
should
now
be
adjusted
by
rotating
in
an anti-clockwise
direction,
so
that the
cam is
just
on
the point
of causing
the contact
break
when
revolving in
the normal
direction, while
at
the same
time the high-tension
rotor
is opposite
No.
r
distributor
contact,
the rotor
being
in
the fully retarded
position.
A convenient
method
of
determining
precisely
when
the
break
takes place
is
by
reference
to the
ammeter.
With
the ignition
switched
on,
and someone
watching
the
ammetei,
the engine
shoutd
be rotated
until
the
required
cam
just
breaks
the
contacts,
as indicated
by
the reading
of the ammeter.
The distributor
head
se-
curing screw should
then be
securely
tightened.
Fie.
45.-lGNlTlON ColL.
f. Coil.
2.
Suppressor condenser.

Tnn ErrcrRrcAl Svsrnu.
95
Ignition
timing
variation during
running is entirely controlled
by
the
centrifugal
governor
incorporated in the distributor,
no
hand
control
being
provided.
Firing
Order
of Cylinders.
The
firing order
of
the engine
is,
r,
4,
z, 6,
3,
5,
No.
front
cylinder.
Sparking
Plugs.
Alternative
plugs are
Champion
Type N8, or Lodge
4
m/m.
non-detachable. Every
5,ooo
miles, as
directed
they
should
be removed and
cleaned.
The
width of the
be checked,
and, if necessary,
reset
to .o3o"
(.262
m/m.).
r being
the
Typ" CLN,
on
page
3r,
gaps
should
Starten
Motor.
The
starter
motor
is
shown
in
Fig.46. A small
planetary
reduction
gear
is
arranged
in
a casing behind
the
motor,
the effect
of which
is
to
provide a total reduction gear ratio between motor and
crankshaft
of
16.o :
r.
A
plug
in the
front
cover of the gear
casr-"g..sl*la.
P.
removed.
every
ro,ooo
miles,
as
directed
on
page
32,
and
oil
"B"
injected until
it is
level
with the orifice.
This oil
also
lubricates
the
driving
end
bearing of the armature
shaft.
Fie. 46.-THE STARTER MOTOR.-UNDERNEATH
VIEW
1.
Oiling
plug.