MG MGB - THE ELECTRICAL SYSTEM; DIAGRAM 11 (Refer to page Nb.2 for the key)

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THE

ELECTRICAL SYSTEM

DIAGRAM 11

(Refer

page

Nb.2

for the key)

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MGB.

Issue

2. 86842

Main Page

Contents2
General Data9
18G, 18Ga9
18Gb18
The Engine36
Table of Contents36
General Description38
Oil Pressure38
Lubrication38
Engine Oil Filter38
Oil Pressure Relief Valve39
Water Pump39
Rocker Assembly39
Manifolds39
Cylinder Head Assembly40
Refitting Rocker Bushes40
The Cylinder Head Components41
Key to the Cylinder Head Components42
Valve Gear and Valves43
Refitting the Cylinder Head43
Removing and Replacing Valves43
Removing and Replacing Valve Guides43
Grinding and Testing Valves and Seatings44
Checking Valve Timing44
Adjusting Valve Rocker Clearances44
The Cylinder Block Components45
Tappets47
Decarbonizing47
Timing Chain Cover48
Timing Chain48
Timing Chain Tensioner49
The Chain Tensioner Components49
Sump and Strainer50
Oil Pump50
Main and Big-End Bearings51
Big—End Bearings51
Main Bearings51
Pistons and Connecting Rods52
Pistons and Gudgeon Pins (18G/18GA)52
Piston Rings52
The Engine Internal Components53
Examination55
Piston Sizes and Cylinder Bored55
Checking the Piston Ring to Groove Clearance55
Checking a Piston Ring Gap55
Renewing the Camshaft Bearings56
Removing the Front and Rear Liners56
Removing the Centre Liner56
Replacing the Front and Rear Liners56
Replacing the Centre Liner57
Reaming the Liners57
Reaming the Centre Liner57
Reaming the Front and Rear Liners57
Removing and Replacing the Crankshaft58
Removing and Replacing the Flywheel58
Fitting Flywheel Starter Rings58
Removing and Refitting the Engine and Power Unit58
The Engine Mountings59
Key to the Engine Mountings60
Engine Controls61
Removing the Power Unit61
Exhaust System62
Closed-Circuit Breathing System62
Distributor Driving Spindle63
Piston and Connecting Rod63
Pistons and Connecting Rods64
18Gb64
Press Fit Gudgeon Pin64
Valve Seat Inserts67
Ignition Timing Indicator67
Valve Seat Machining Dimensions67
Valve Gear68
Front Cover and Oil Seal68
Later Engines68
Single Valve Spring68
Timing Chain and Tensioner69
Timing Chain Tensioner Assembly70
Engine Restraint72
The Ignition System73
Distributor74
Cam Bearing74
Cam74
Automatic Timing Control74
Servicing the Distributor75
Contact Breaker Points75
Vacuum Advance75
Centrifugal Advance75
Removing and Replacing the Distributor76
Dismantling the Distributor76
The Distributor Components76
Examining the Distributor77
Assembling the Distributor77
Static Ignition Timing77
Tassembling77
Texamining77
High-Tension Cables78
The Vernier Adjustment Nut78
The Correct Method of Connecting High-Tension Leads78
Ignition Coil78
Sparking Plugs79
Locating the Cause of Uneven Firing79
Testing the Low-Tension Circuit79
Locating a Low-Tension Circuit Fault80
Renewing Contact Breaker Points80
Removing a Contact Breaker Set—Lucas 45D480
Contact Breaker Gap—Checking—Adjusting81
Distributor Cap81
Distributor Dwell Angle81
Refitting the Drive Dog (Lucas Type 45D4)82
Refitting the Base Plate (Early Cars)(Lucas Type 45D4)82
The Cooling System84
Thermostat88
Temperature Gauge88
Draining, Flushing and Refilling the Cooling System88
Removing the Filler Cap88
The Fan and Water Pump Component89
Key to the Fan and Water Pump Components90
Fan Belt91
Radiator and Diaphragm91
Filling the Cooling System91
Cold Weather Precautions93
Pump with Later-Type Seal,Thrower Deleted93
Draining and Refilling the Cooling System94
Radiator94
Fan Motor94
Fan Motor Test95
Radiator Fan Motor Components95
The Fuel System97
The auf 300 and HP Fuel Pump Components99
Body and Valves100
Type HP100
Pedestal and Rocker101
Diaphragm Assembly101
Body Components101
Contact Blade103
Contact Gap Settings103
Modified Rocker Assemblies103
Earlier-Type Rocker Assemblies103
Priming104
Air Leak Check104
Valve Seat Check104
Delivery Check104
Faulty Diaphragm Action105
Noisy Pump105
Pump Operates Without Delivering Fuel105
The Carburetor Components106
Key to the Carburetor Components107
Carbuterrors108
Slow-Running Adjustments and Synchronization108
Checking the Nylon Float Level108
Jet-Centring109
Float-Chamber109
Float-Chamber Flooding109
Float Needle Sticking109
Air Cleaners110
Needles110
Piston Sticking110
Filter Replacement110
Carburetter Tuning (S.U. HIF4)111
Carburetter Installation (S.U. HIF4)112
Suction Chamber Timing Check (S.U. H11)113
The S.U. Type HIF Carburetter Components114
Throttle Pedal116
Throttle Cable116
Fuel Pump116
Fuel Tank118
Vapour Separator Tank118
Leak Testing118
The Clutch119
The Clutch Components120
Clutch Assembly121
A Section through the Clutch121
Servicing the Clutch122
Master Cylinder122
Tolerances122
Condition of Clutch Facings in Service122
Slave Cylinder123
The Clutch Control Components124
Key to the Clutch Control Components125
Bleeding the Clutch System126
Bleeding the Clutch Hydraulic System at the Slavecylinder126
The Gearbox127
The Gearbox Components128
Key to the Gearbox Components129
Removing the Gearbox130
Dismantling the Gearbox130
Dismantling and Assembling the Control Timer131
Dismantling and Assembling the Rear Extension131
Dismantling and Assembling the First Motion Shaft132
Dismantling and Assembling the Laygear132
Dismantling the Third Motion Shaft132
Examination of Components132
Assembling the Third Motion Shaft133
Assembling the Gearbox133
Fitting Replacement Bushes134
Reverse Gear134
Clutch Withdrawal Fork134
Fitting the Gearbox Front Cover135
Third Motion Shaft Bushes135
The Overdrive136
The Overdrive Components137
Key to the Overdrive Components138
Direct Drive139
Overdrive Engaged139
Guide to Service Diagnosis140
Hydraulic System—Direct Drive140
Hydraulic System —Overdrive140
Pump Non-Return Valve142
Relief Valve142
Hydraulic Lever Setting142
Overdrive Does Not Release142
Operating Valve143
Testing Oil Pressure143
Reassembling the Unit144
Drive Shaft Bearings and Seal146
Overdrive Relay System146
Cable Colour Code146
Gearbox Assembly148
Rear Extension148
Front Cover149
Selector Rods and Forks150
First Motion Shaft150
Reverse Idler Gear150
Third Motion Shaft151
Fault Diagnosis161
Overdrive Does Not Engage161
Overdrive Does Not Disengage161
Overdrive Slips When Engaged161
Filters162
Relief and Low Pressure Valve162
Solenoid Valve162
Pump and Non-Return Valve163
Overdrive Assembly163
Overdrive Unit163
Overdrive Adaptor163
Using the Bridge-Pieces to Remove the Thrust Rods164
Fitting the Rear Bearing Using Tool 18G 186164
The164
Fitting the Rear Oil Sealusing Tool 18G 177166
Using Tool 18G 185 to Align the Splines166
The Automatic Gearbox168
Selector178
The Selector Rod Adjuster178
Dipstick and Filler Tube178
Road Test Procedure179
Topping up Fluid179
Refilling after Draining179
Towing for Recovery179
Converter Fault Diagnosis180
Stall Test180
Air Pressure Test183
Down-Shift and Throttle Valve Cable183
Front Clutch and Governor Feed183
Front Brake Band183
Transmission Assembly184
Torque Converter184
Governor Assembly and Speedometer Drive184
Rear Clutch184
Valve Bodies Assembly185
Governor and Speedometer Drive Gear185
The Governor Components185
The Valve Bodies Separated186
The Check Valves in the Lower Valve Body186
Location of the Oil Tubes186
The Lower Valve Body187
Location of the Pump and Converter Oil Tubes187
Front Servo188
Rear Servo188
The Upper Valve Body188
Pump189
Withdrawing the Pump Assembly189
Using Tool 18G 674 to Check the Gear Train End-Float189
Front Clutch190
Fitting Order for the Thrust Washer Sand Front Clutch191
The Rear Clutch Components191
Centre Support and Planet Gears192
Forward Sun Gear Components192
Using Tool 18G 702 to Refit the Rear Clutch Piston192
Fitting the Rear Clutch and Forward Sun Gear192
Driven Shaft and Ring Gear193
The Gear Train Components193
The Drive Shaft193
Manual Valve Shaft and Lever194
The Propeller Shaft195
The Propeller Shaft Components196
Key to the Propeller Shaft Components197
Removing and Replacing the Propeller Shaft198
Dismantling the Propeller Shaft198
Examining the Propeller Shaft199
Assembling the Propeller Shaft199
Propeller Shaft - Sealed Type200
The Rear Axle and Suspension201
The Rear Axle Components202
Key to the Rear Axle Components203
Removing and Replacing a Brake-Drum and Axle Shaft204
Removing and Replacing a Hub204
Renewing the Pinion Oil Seal205
Removing the Differential Pinions205
Replacing the Differential Pinions205
Dismantling the Crown Wheel and Pinion206
Assembling and Setting the Crown Wheel and Pinion206
Setting the Pinion Position206
Adjusting Pinion Bearing Preload208
Setting the Crown Wheel Position208
Table of Washer and Shim Thicknesses208
Removing and Refitting the Axle210
Crown Wheel and Pinion Markings210
Measuring the Crown Wheel Backlash210
Rear Road Springs211
Dismantling and Assembling a Rear Spring211
To Refit a Rear Spring211
The Rear Suspension Components212
Key to the Rear Suspension Components213
The Rear Axle and Rear Suspension214
Axle Unit215
Hub and Axle Shaft215
Pinion Bearing Preload219
Available Washers for Pinion Position219
Available Spacers for Differential Assembly220
Adjusting the Backlash221
Road Springs221
Rear Anti-Roll Bar Components222
Rear Anti-Roll Bar Locator Dimension223
The Steering Gear224
The Steering Gear Components225
Key to the Steering Gear Components226
Front Wheel Alignment227
Steering Wheel227
Steering Column227
Steering Column Universal Joint228
Steering Gear228
The Assembly of a Tie-Rod Ball Joint228
Rack and Pinion229
Examining for Wear229
Steering Column Alignment230
Steering Lock Ignition Switch230
Nylon-Seated Ball Joints230
Steering Lock and Ignition Starter Switch231
Rack Assembly233
Steering Alignment234
The Front Suspension235
Front Hubs236
Removing a Hub236
Coil Spring237
Swivel Axles237
Refitting a Hub237
The Front Suspension Cross-Member and the Suspension Units237
The Front Suspension Components238
Key to the Front Suspension Components239
Removing and Refitting Bushes240
Front Suspension Unit240
Swivel Axle Bushes240
Additional Swivel Pin Graease Nipple241
Anti-Roll Bar Components242
Anti-Roll Bar243
Front Anti-Roll Bar Components243
Front Anti-Roll Bar Locator Dimension244
Hydraulic Dampers245
The Rear Hydraulic Damper246
Maintenance247
Removing and Replacing the Dampers247
Testing the Dampers247
The Braking System249
Brake Pedal250
Brake Adjustment250
Hand Brake251
Bleeding the Brake System251
The Brake Master Cylinder252
Disc Brake Units253
Removing a Calliper Unit253
Removing the Disc Friction Pads253
Friction Pad Retaining Pins and Bleed Screw Location253
The Disc Brake Components254
Removing the Calliper Pistons255
A Disc Brake in Section255
Brake Discs256
Flexible Hoses256
Rear Brake Assembly256
The Rear Brake Components257
Relining the Brake-Shoes258
Rear Brake Backplate258
Servo Unit259
The Air Valve Assembly Components and Piston259
Servo Cylinder Assembly260
Slave Cylinder Assembly260
Vacuum Servo Components261
Air Valve Assembly262
Pedal Free Movement265
Tandem Master Cylinder265
Pressure Failure Switch Assembly266
A Section through the Master Cylinder266
The Electrical System268
Battery269
Fast Charging269
Adjustments in the Vehicle269
Preparing Dry-Charged Batteries for Service270
Preparing New Unfilled, Unchanged Batteries for Service270
Recharging from an External Source270
Putting into Use270
Dynamo271
Initial Charge271
Testing on Vehicle When Dynamo Is Not Charging271
The C40/1 Type Dynamo272
Brushes272
Commutator272
Field Coils273
Armature273
Bearings273
Fitting the Commutator End Bracket273
Control Box Model RB340274
Expanding the Pole-Shoesin the Yoke274
Preliminary Checking of Charging Circuit275
Cut-Out Relay275
Cut-In Adjustment275
Voltage Regulator (Open Circuit)275
Starter276
Current Regulator276
Adjustment of Air Gap Settings276
Cleaning Contacts276
The Starter Motor Components277
Key to the Starter Motor Components278
Examination of Commutator and Brush Gear279
Drive279
Windshield Wiper281
Wiper Takes no Current281
Regulator and Fuse Block281
Resetting the Limit Switch281
Wiper Takes Abnormally Low Current282
Wiper Takes Abnormally High Current282
Removing the Motor, Gearbox, and Wheelboxes282
Wiper Arm Fixing Details282
The Windshield Wiper Components283
Key to the Windshield Wiper Components284
Armature Bearings285
Dismantling the Motor285
Dismantling the Gearbox Unit285
Light Unit Retaining Screws285
Headlamps286
Removing a Light Unit286
Bulb Replacement286
Refitting a Light Unit286
Side and Direction Indicator Lamps287
Tail and Stop and Direction Indicator Lamps287
Number-Plate Lamps287
Panel, Map and Warning Lights287
Horn288
Flasher Unit288
Removing the Horn288
A Rear Number-Plate Lamp (Early Cars)288
The Switches289
Key to the Switches290
Switches291
Location and Remedy of Faults291
Functions of Warning Lamp291
Checking Faulty Operation291
Charging Circuit292
Starter Motor292
Lighting Circuit292
Bi-Metal Resistance Instrumentation292
Battery Voltage293
Wiring293
Voltage Stabilizer293
Gauges293
Electrically Heated Back Light294
Cigar Lighter294
Charging System294
Alternator295
The 16AC Alternator Components295
16AC Alternator Outpu Test Circuit295
Slip - Rings297
Rotor297
Stator297
Diodes297
Testing in Position298
Charging Circuit Resistance Test298
Removing the Regulator298
Windshield Wipers - Two Speed299
Motor and Gearbox Assembly299
Wheelboxes299
The Two-Speed Windshield Wiper Motor Components299
Brush Gear301
Commutator End Bracket302
Drive Clutch302
Light Running Test303
Torque Test303
Heater, Wiper and Lighting Switches303
Console Switches303
Ignition Switch304
Direction Indicator/Headlight Flasher/Low-High Beam Switch304
The Starter Motor—Lucas Type 2M100 Pre-Engaged305
Starter Motor Relay306
Solenoid - Coil306
Solenoid Contacts306
Brake Warning Switch307
Light Switch307
Ignition Starter Switch and Steering Lock307
Fascia Switches307
Panel Lamp Rheostat Switch308
Direction Indicator/Main Beam/Horn Control Switch308
Instruments and Switches311
Tachometer311
Oil Pressure Gauge311
Speedometer311
Windshield Wiper/Washer and Overdrive Switch312
Direction Indicator; Horn and Headlamp Flasher Switch312
Hazard Warning Switch312
Map Light Switch312
Windshield Washer Motor313
Lamps313
Hazard Warning Flasher Unit and Audible Warning Buzzer313
Switches, Warning Lamps and Controls313
Heater Blower Switch314
Seat Belt Warning Lamp314
Hazard Warning Lamp314
Temperature Rotary Control314
Air Flow Rotary Control315
Lighting Switch315
Seat Belt Warning Lamp and Buzzer - Seat Belt Switch316
Seat Belt Warning Lamp and Buzzer - Gearbox Switch316
Sequential Seat Belt System Control Unit316
Sequential Seat Belt System Circuit Wiring Diagram318
Cable Color Code318
Wiring Diagrams321
Key to the Wiring Diagrams322
The Wheels and Tyres342
Jacking up the Gear343
Tyre Replacement343
The Side-Lift Jack343
Removing the Hub Cap (Disc Wheels)343
Removing and Replacing Road Wheels344
Valves344
Tyre Removal344
Inspection of Wheels and Tyres344
Repair of Tyres and Tubes345
Fitting Tyres and Tubes345
Wire Wheels345
Tyres345
Wheel and Tyre Balance346
Factors Affecting Tyre Life346
Balancemarks on Tyre and Tube346
Effect of Temperature347
Climatic Conditions347
Road Surface347
Impact Fractures347
High-Speed Tyre Pressure Conditions348
The Body350
Front Grille351
Bonnet and Bonnet Lock351
Windscreen351
A Section through a Windscreen Pillar351
Door Trim Pad352
Door Glass352
The Door Assembly(Early Tourer Models)352
Door Glass Regulators353
Window Regulators and Interior Door Handles353
Strikes353
Door Locks353
Door Lock Remote Control Unit354
Outer Door Handles354
Private Lock354
Seats355
Luggage Compartment Lock355
Luggage Compartment Lid355
Rear Quarter-Light355
Windscreen and Back-Light Glasses356
Fascia Panel, Instruments and Controls356
Body Alignment357
Paint Refinishing Instructions359
The Door Components363
Key to the Door Components364
The Window Components365
Key to the Window Components366
The Fascia Panel Components367
Key to the Fascia Panel Components368
The Heater Components369
Key to the Heater Components370
Bodywork371
Bumpers371
Coachwork371
Carpets371
Eelctrically Heated Back-Light372
Seat Belts372
Rear Wheel Arch372
Drive Shaft Tunnel372
Heater373
Door Lock Adjustment373
Interior Door Handles and Trim Pad373
Outside Door Handles374
Remote Control Unit374
Latch Unit374
Exploded View of Door Lock Mechanism375
Front Bumper Assembly377
The Front Bumper Components377
Rear Bumper Assembly377
Fascia378
Console378
Vertical Alignment Check380
The Fascia Components381
Key to the Fascia Components382
Heater Fan Motor384
Heater Water Valve384
Heater Matrix384
Heater Air Flow Control Cable384
Heater Controls385
Heater Temperature Control Cable385
Glovebox and Lid388
Face-Level Vents388
Short Belt389
Long Belt and Reel389
Anti-Burst Door Units390
The Front Bumper and Over-Riders390
The Front Bumper Assembly391
The Rear Bumper Assembly392
Service Tools394
Serviec Lubricants417

MG MGB - THE ELECTRICAL SYSTEM; DIAGRAM 11 (Refer to page Nb.2 for the key)

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