1 9 7 3
VOLVO
142 144 145

pg. 33 TECHNICAL DESCRIPTION


ENGINE COMPARTMENT
1 Radiator
2 Expansion tank
3 Charging relay
4 Air cleaner
5 Pressure sensor
6 Relay for fuel pump
7 Main relay for fuel injection
8 Foam plastic filter, evaporative control system
9 Vacuum container for heating system
10 Windshield wiper motor
11 Inlet duct
12 Alternator
13 Auxiliary air regulator
14 Pressure regulator
15 Injector
16 Temperature sensor, coolant
17 Oil filler cap
18 Windshield fluid container
19 Data plate
20 Ignition coil
21 Distributor
22 Dipstick
23 Brake fluid container
24 Fusebox
25 Step relay, fullbeam-dipped headlights
26 Battery
27 Steering box

pg. 34 TECHNICAL DESCRIPTION


ENGINE
The engine is a four-cylinder, water-cooled unit with overhead valves.
The cylinder block is made of special alloy cast iron and is cast in a single unit. The cylinder liners, which are surrounded by cooling jackets, are machined directly in the block. The cylinder head has separate inlet and exhaust ports, one for each valve.

Lubricating system
Engine lubrication is taken care of by a gear pump located under the crankshaft in the sump. The pump is driven by a gear from the camshaft.
From the pump the oil is forced through the oil filter and then along oilways to the various lubricating points. A relief valve is built into the oil filter and prevents the oil pressure from reaching excessively high values. The oil filter is of the full-flow type, that is, all the oil passes through the filter before continuing on to the engine lubricating points.

pg. 35 TECHNICAL DESCRIPTION

Fuel system
The engine is fitted with an electronic fuel injection system.
This system includes an electronic control unit (7) which converts the impulses from the various sensors in the engine to control signals which regulate the four solenoid-actuated fuel injectors (15). The control signals influence the opening times of the injectors and thereby the amount of fuel injected.
The mixture of fuel and air is modified the whole time according to the conditions under which the engine is running. Engine speed is governed by the triggering contacts (13) in the distributor, the operating temperature by the sensor (18) for the coolant, the temperature of the induced air by the sensor (1) and the engine load by the pressure sensor (6) which is connected to the inlet duct. In addition, the control unit is provided with information concerning the position of the throttle valve by means of the throttle valve switch (3). This information is "computerized" in the control unit and re-transmitted in the form of control impulses to the injectors.
Fuel is injected into the inlet ports in the cylinder head just before the intake valves. The fuel is delivered to the injectors via an electric fuel pump (11) which maintains a constant pressure of 30 psi (2 kp/cm2) in the fuel line with the help of a pressure regulator (14).
The car is fitted with a system to check fuel evaporation from the fuel tank.

Principle of operation, fuel injection system
1. Temperature sensor for induction air
2. Air cleaner
3. Throttle valve switch
4. Cold start valve
5. Inlet duct
6. Pressure sensor
7. Control unit (electronic)
8. Battery
9. Fuel tank
10. Fuel filter, suction side
11. Fuel pump
12. Fuel filter, discharge side
13. Triggering contacts in distributor
14. Pressure regulator
15. Injectors
16. Thermal timer contact
17. Idling adjusting screw
18. Temperature sensor for coolant
19. Auxiliary air regulator

pg. 36 TECHNICAL DESCRIPTION


Exhaust emission control
Your Volvo is equipped with exhaust emission control, that is, a system which as a result of better mixing and distributing of fuel and air provides a more complete combustion and thereby cleaner exhaust gases.
The exhaust emission control is provided by the fuel injection system.

Cooling system
The cooling system is of the sealed pressure type and incorporates a circulation pump. An expansion tank prevents air from circulating with the coolant as this would cause corrosion in the cooling system.
The fan is driven via a slip coupling which permits a max. fan speed of approx. 2,500 rpm, resulting in a lower noise level.

POWER TRANSMISSION
Clutch

The function of the clutch is to transmit power from the engine to the transmission. The clutch is of the single dry plate type. Pressure on the pressure plate is obtained from a diaphragm spring which in its turn is controlled by the clutch pedal via the throw-out yoke.

pg. 37 TECHNICAL DESCRIPTION


Transmission
The transmission has synchromesh on all forward gears. Since it is fitted with helical gears and the gear lever is rubber-insulated, good sound insulation is obtained.

Automatic transmission
As an alternative, your Volvo can be fitted with a BW 35 automatic transmission. In principle it consists of two main components - a hydraulic torque converter and a hydraulically operated epicyclic gearbox with a control system. The converter serves as a clutch and as an extra gear between engine and transmission.

Overdrive
As an alternative the Volvo 142 can be fitted with an overdrive. With the overdrive, it is possible to reduce engine speed while maintaining road speed. This is less wearing on the engine and reduces fuel consumption at the same time.

pg. 38 TECHNICAL DESCRIPTION


Final drive
Engine torque is transmitted via the propeller shaft to the rear wheels through the final drive. The final drive is of the hypoid type, that is, the drive pinion lies below the center line of the drive shafts.

Limited slip
A limited slip differential can be obtained as extra equipment. A rear axle with a limited slip automatically transmits the tractive power to the wheel having the best road grip when a wheel begins to spin. Except for the differential, the rear axle is similar in design to a conventional rear axle.
Do not rotate a jacked-up rear wheel if the other rear wheel is still on the ground. Due to the differential, there is still drive on the wheel in contact with the ground. Rotating the jacked-up rear wheel would thus move the other rear wheel and may cause the car to topple off the jack.

Rear axle
The rear axle is carried on two support arms the front ends of which are bolted to the body. The rear axle casing is secured to the trailing arms by means of levers. Two torque rods are journalled on the casing and the body. A "Panhard" rod prevents lateral movement of the body and rear axle in relation to each other.

pg. 39 TECHNICAL DESCRIPTION


FRONT END AND STEERING
Front end

The front suspension units are mounted on a strong box member. The member is bolted firmly to the front section of the body. The front wheels are journaled in tapered roller bearings. The front springs consist of coil springs in which telescopic shock absorbers are fitted. The car is provided with stabilizers secured to the lower control arms and to the body.

Steering
The steering is of the cam-and-roller type. Movements of the steering wheel are transmitted via the worm on the steering column to the roller on the pitman shaft, which in turn operates the wheels through a linkage system.

HEATING SYSTEM
The heating system is a combined warm and fresh air system. The incoming fresh air is blown by a fan through the cell system of the element into the vehicle. By means of the various ventilation controls, the fresh air can be warmed up and directed to suitable places in the car.
From there the air passes out of the car through a number of extractor vents under the rear window. This system provides good ventilation in the vehicle as well as effective demisting of the tailgate window and side windows.

pg. 40 TECHNICAL DESCRIPTION

ELECTRICAL SYSTEM
The electrical system is of the 12-volt type and is fitted with a voltage-regulated alternator. The starter motor is operated by means of the ignition switch. This switch is also the main switch for the rest of the electrical system. The headlights, parking lights and interior lighting, however, are not wired via the ignition switch so they can be switched on and off without the ignition key being in position.

Lighting
The front lighting on the vehicle consists of two headlights (full and dipped beam) together with two turn signals and a parking light. At the rear, the lighting consists of two tail lights, turn signals, brake warning lights and reversing lights. There are also two lights for the rear license plate.
The car is also fitted with marker lights mounted on the side of the fenders.
The interior lighting consists of a roof light and one in the glove compartment.
Concerning replacement of bulbs, see pages 58, 59, 60 and 61.

Wiring diagram, 142, 144
1. Battery, 12V, 60 Ah
2. Connection box
3. Ignition switch
4. Ignition coil
5. Distributor, firing order 1-3-4-2
6. Starter motor
7. Alternator
8. Charging regulator
9. Fusebox
10. Lighting switch
11. Step relay for fullbeam and dipped headlights also headlight flasher
12. Fullbeams
13. Dipped headlights
14. Parking lights, 5W
15. Tail lights. 5W
16. Side marking lights, 5W
17. License plate light, 2x5 W
18. Brake light contact
19. Brake stop lights, 32 cp
20. Connection at instrument
21. Contact on gearbox. M 40, M 41
22. Reversing lights, 32 cp
23. Flasher unit
24. Turn signal switch
25. Switch for emergency warning flashers
26. Flashers, 32 cp
27. Part of 6-pole connection panel
28. Rev counter
29. Temperature gauge
30. Fuel gauge
31. Voltage stabilizer
32. Warning light for flasher, 1.2 W
33. Diode
34. Warning light for headlight fullbeams, 1.2 W
35. Warning light for battery charging, 1.2W
36. Warning light for parking brakes, 1.2 W
37. Warning light for choke, 1.2W
38. Warning light for oil pressure, 1.2 W
39. Warning light for brake failure, 1.2W
40. Warning light, vacant, 1.2 W
41. Brake warning contact
42. Choke control contact
43. Temperature sensor
44. Oil pressure sensor
45. Brake warning contact
46. Fuel level sender
47. Horn
48. Horn pad
49. Lever for windshield wipers/washer
50. Windshield wipers
51. Windshield washer
52. Switch, fan
53. Fan
54. Switch for electrically heated rear window
55. Electrically heated rear window
56. Clock
57. Cigarette lighter
58. Rheostat for instrument panel lighting
59. Instrument panel lighting, 3X2 W
60. Control panel lighting, 3X1.2 W
61. Shift positions light, 1.2W
62. Glove locker contact
63. Glove locker light, 2 W
64. Interior light, 10 W
65. Door contact, left
66. Door contact, right
67. Warning buzzer, ignition key
68. Connector
69. Connection at instrument
70. Passenger seat contact
71. Buzzer reminder for seat belt
72. Seat belt reminder light, 1.2 W
73. Contact for seat belt
74. Switch for overdrive
75. Switch for overdrive, on transmission
76. Solenoid for overdrive
77. Warning lamp for overdrive, 1.2W
78. Switch on transmission BW 35
79. Reminder buzzer for mainbeams
80. Control unit
81. Throttle valve switch
82. Pressure sensor
83. Relay for fuel pump
84. Main relay for fuel injection
85. Thermal timer contact
86. Cold start valve
87. Temperature sensor I
88. Temperature sensor II
89. Injection valves
90. Triggering contacts
91. Spark plugs
92. Fusebox
93. Fuel pump
94. Connection at instrument
95. Connection at Instrument

Colour code:
SB = Black R = Red
Y = Yellow GN = Green
BL = Blue W-R = White-red
BL-Y = Blue-yellow W = White
BL-R = Blue-red BR = Brown
GN-R= Green-red GR = Gray

pg. 41 TECHNICAL DESCRIPTION


pg. 42 TECHNICAL DESCRIPTION

Wiring diagram, 145
1. Battery, 12V, 60 Ah
2. Connection box
3. Ignition switch
4. Ignition coil
5. Distributor, firing order 1-3-4-2
6. Starter motor
7. Alternator
8. Charging regulator
9. Fusebox
10. Lighting switch
11. Step relay for fullbeam and dipped headlights also headlight flasher
12. Fullbeams
13. Dipped headlights
14. Parking lights, 5 W
15. Tall lights, 5W
16. Side marking lights, 5W
17. License plate light, 2x5 W
18. Brake light contact
19. Brake stop lights, 32 cp
20. Connection at instrument
21. Contact on gearbox, M 40, M 41
22. Reversing lights, 32 cp
23. Flasher unit
24. Turn signal switch
25. Switch for emergency warning flashers
26. Flashers, 32 cp
27. Part of 6-pole connection panel
28. Rev counter
29. Temperature gauge
30. Fuel gauge
31. Voltage stabilizer
32. Warning light for flasher, 1.2 W
33. Diode
34. Warning light for headlight fullbeams, 1.2 W
35. Warning light for battery charging, 1.2 W
36. Warning light for parking brakes, 1.2 W
37. Warning light for choke, 1.2 W
38. Warning light for oil pressure, 1.2 W
39. Warning light for brake failure, 1.2 W
40. Warning light, vacant, 1.2 W
41. Brake warning contact
42. Choke control contact
43. Temperature sensor
44. Oil pressure sensor
45. Brake warning contact
46. Fuel level sender
47. Horn
48 Horn pad
49. Lever for windshield wipers/washer
50. Windshield wipers
51. Windshield washer
52. Switch, fan
53. Fan
54. Switch for electrically heated rear window
55. Electrically heated rear window
56. Clock
57. Cigarette lighter
58. Rheostat for instrument panel lighting
59. Instrument panel lighting, 3X2 W
60. Control panel lighting, 3X1.2 W
61. Shift positions light, 1.2 W
62. Glove locker contact
63. Glove locker light, 2W
64. Interior light, 10 W
65. Door contact, left
66. Door contact, right
67. Warning buzzer, ignition key
68. Connector
69. Connection at instrument
70. Passenger seat contact
71. Buzzer reminder for seat belt
72. Seat belt reminder light, 1.2 W
73. Contact for seat belt
74. Switch for overdrive
75. Switch for overdrive, on transmission
76. Solenoid for overdrive
77. Warning lamp for overdrive, 1.2W
78. Switch on transmission BW35
79. Reminder buzzer for mainbeams
80. Switch for tailgate window wiper/washer
81. Tailgate wiper
82. Tailgate washer
83. Interior light, rear (145)
84. Control unit
85. Throttle valve switch
86. Pressure sensor
87. Relay for fuel pump
88. Main relay for fuel injection
89. Thermal timer contact
90. Cold start valve
91. Temperature sensor I
92. Temperature sensor II
93. Injection valves
94. Triggering contacts
95. Spark plugs
96. Fusebox
97. Fuel pump
98. Connection at instrument
99. Connection at instrument

Colour code:

SB = Black
Y = Yellow
BL = Blue
BL-Y = Blue-yellow
BL-R = Blue-red
GN-R= Green-red
R = Red
GN = Green
W-R = White-red
BR = Brown
W = White
GR = Gray

pg. 43 TECHNICAL DESCRIPTION


pg. 44 TECHNICAL DESCRIPTION


BRAKES
The brake system is of the two-circuit type with disc brakes all round. The system is provided with a tandem-type master cylinder and a directly-operating booster cylinder. When the brake pedal is depressed, the master cylinder is operated mechanically via the booster cylinder, this increasing the pedal force about three times. The brake pressure is transmitted hydraulically from the master cylinder through the brake to the wheel cylinders. The pistons in these are then pressed outwards and apply the brake pads. The pressure lines to the rear wheel brakes are provided with a reducer valve which prevents locking of the rear wheels. The principle of the two-circuit system is that both the front wheels are connected to one rear wheel, that is, should there be a failure in one of the circuits, there is always braking power on both front wheels and the other rear wheel. So at normal pedal pressure the braking effect of one of the circuits is 50 %, but when pedal pressure is increased, about 80% of the full braking power can be obtained in the one circuit. This provides maximum safety and prevents lateral dragging and rear-end lurching. With the engine stopped, the booster assists the braking a further two or three times after which the pedal pressure must be increased about three times as much in order to obtain a braking power corresponding to the braking power available with the engine running. The parking brake operates the rear wheels mechanically as the brake discs have also been designed as brake drums in order to incorporate the shoes for the parking brake.


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