The battery is carried under the bonnet on the right of the engine.
The electrolyte level should be checked at intervals of 1,000 miles (1.500 Km.) in the following manner:- Remove the filler plug from each cell of the battery and examine the level of the electrolyte in each cell. If necessary, add sufficient distilled water to bring the electrolyte level with the tops of the separators. A hydrometer will be found useful for topping up as' it prevents the distilled water from being spilled on top of the battery. Do not use tap water and do not use a naked light when examining the condition of the cells. Examine the terminals and if they are corroded, scrape them clean and coat with petroleum jelly.

Fig. 27. Topping-up battery, using a hydrometer.

Wipe away all dirt and moisture from the top of the battery and make sure that the connections are clean and tight.
NOTE : -In hot climates it will be necessary to top-up the battery at more frequent intervals.
In very cold weather it is essential that the vehicle be used immediately after topping-up, to ensure that the distilled water is thoroughly mixed with the electrolyte. Neglect of this precaution may result in the distilled water freezing and causing damage to the battery.

Occasionally check the condition of the battery by taking hydrometer readings of the specific gravity of the electrolyte 'in each of the cells. Readings should not be taken immediately after "topping-up" the cells. The specific gravity readings and their indications are as follows -
1.280-1.300 (320-340 Baumé) Battery fully charged.
About 1.210 (250 Baumé) Battery about half discharged.
Below 1.150 (190 Baumé) Battery fully discharged.

These figures are given assuming the temperature of the solution is 600F. (15.5C.). If the electrolyte temperature exceeds this, .002 must be added to hydrometer readings for each ST. (3C.) rise to give the true specific gravity at 600F. (15.5C.). Similarly .002 must be subtracted from hydrometer readings for every 50F. (3C.) below 600F. (15.5C.).
The readings for all cells should be approximately the same. If one cell gives a reading very different from the rest, it may be that acid has been spilled or has leaked from this particular cell or there may be a short circuit between the plates. In this case the battery should be examined by a Lucas Service Depot or Agent.

Fig. 28. Taking hydrometer readings.

A-Hold tube vertical.
B-Take readings at eye level.
C-Float must be free.
D-Do not draw in too much electrolyte.

When taking specific gravity readings, examine the condition of the electrolyte in the hydrometer; it should be fairly clear. It is very dirty, it is possible that the plates are in a bad condition and the battery should be sent to a Lucas Service Depot or Agent for overhaul.
NOTE -If the vehicle is to be left in the open in very cold weather, care must be taken to ensure that the battery is in a good state of charge, otherwise there is danger of the electrolyte freezing and consequent damage to the battery.

The dynamo is of the compensated voltage type and operates in conjunction with the regulator unit which is housed along with the cut-out in the control box.
The regulator causes the dynamo to give an output which varies according to the load on the battery and its state of charge. When the battery is discharged, the dynamo gives a high output so that the battery receives a quick recharge which brings it back to its normal state in the minimum possible time.
On the other hand, if the battery is fully charged, the dynamo is arranged to give only a trickle charge which is sufficient to keep it in good condition without any possibility of causing damage to the battery by overcharging.
The regulator also causes the dynamo to give a controlled boosting charge at the beginning of a run which quickly restores to the battery the energy taken from it when starting. After about 30 minutes running, the output of the dynamo falls to a steady rate, best suited to the particular state of charge of the battery.
At about every 18,000 miles (30.000 Km.) or 500 hours, unscrew the lubricator at the end of the dynamo, lift out the felt pad and spring and about half fill the lubricator with high melting-point grease. Replace the spring and felt pad.
When the vehicle is under-going a general overhaul, say after about 50,000 miles (80.000 Km.), it is advisable to have the dynamo checked for brush or commutator wear by a Lucas Service Depot or Agent.
Occasionally inspect the dynamo driving belt and adjust if necessary to take up any undue slackness by turning the dynamo on its mounting (see "FAN BELT"). Care should be taken to avoid over-tightening the belt and to see that the machine is properly aligned, otherwise undue strain will be thrown on the dynamo bearings.

Ammeter Readings. When noting ammeter readings, it must be remembered that during daytime running when the battery is in good condition, the dynamo gives a trickle charge, so that the charge reading will seldom be more than three or four amperes.

A discharge reading may be given immediately after switching on the headlamps. This usually happens after a long run, when the voltage of the battery is high. After a short time, the battery voltage will fall, and the regulator will respond, causing the dynamo output to balance the load.

When starting from cold, the cha~ging current will rise until it reaches a steady maximum at a speed of say, 20 m.p.h. (35 k.p.h.) after which it will remain fairly high for about 10 minutes and then fall to a steady charge which is most suitable for the particular state of charge of the battery.
It will be noticed from the ammeter readings that the dynamo does not charge at very low engine speeds. This is because it is not rotating fast enough to generate sufficient energy to charge the battery. The cut-out, which is an automatic switch connected between the dynamo and the battery, allows the flow of current from the dynamo to the battery only. It closes when the dynamo is running fast enough to charge the battery and opens when the speed is low or the engine is stationary, thus preventing current flowing from the battery through the dynamo windings.

This unit is mounted on the scuttle and houses the cut-out, dynamo voltage regulator and fuses.
The cut-out and regulator are accurately set before leaving the works and they must not be tampered with. The cover protecting them is sealed.

The fuse marked "AUX~' protects the accessories which are connected so that they operate irrespective of whether the ignition is on or off.
The fuse marked AUX IGN " protects the accessories which are connected so that they operate only when the ignition is switched on.
A blown fuse is indicated by the failure of all the units protected by it, and is confirmed by examination of the fuse, which can easily be withdrawn from the spring clips in which it fits. If it has blown, the broken ends of the wire will be visible inside the glass tube.
Before replacing a blown fuse, inspect the wiring of the units that have failed for evidence of a short circuit or other fault which may have caused the fuse to blow and remedy the cause of the trouble first.
Spare fuses are carried on the control box cover and it is important to use replacements of the correct value; the fusing value is marked on a coloured paper slip inside the glass tube of the fuse.

Fig. 29 Blown fuse

If the new fuse blows immediately and the cause of the trouble cannot be found, have the equipment examined at a Lucas Service Depot.

When starting, observe the following points: --
1. See that the controls are properly set.
2. Operate the starter switch firmly and release it as soon as the engine fires.
3. Do not operate the starter when the engine is running. If the engine will not fire at once, allow it to come to rest before operating the switch again.
4. Do not run the battery down by keeping the starter on when the engine will not start.

In the event of the starter pinion becoming jammed in mesh with the flywheel, it can usually be freed by turning the starter armature by means of a spanner applied to the shaft extension at the commutator end. This is accessible by pulling off the small cap which is secured by two screws.

If any difficulty is experienced with the starter not meshing correctly with the flywheel, it is probable that the presence of dirt on the starter drive is preventing the free movement of the pinion on its sleeve and the sleeve and pinion should be washed with paraffin. Alternatively, the drive may have been damaged owing to mis-use.
As in the case of the dynamo, the starter brushgear and commutator will not normally require attention by the owner, but should be checked by a Lucas Service Depot or Agent when the car is undergoing a general overhaul.

The coil requires no attention beyond keeping its exterior clean, particularly between the terminals, and occasionally checking that the terminal connections are quite tight.

The contact breaker clearance should be checked and adjusted in the following manner: -Remove the moulded distributor cap and turn over the engine by hand until the contacts in the distributor are fully opened. Check the gap with the gauge on the screwdriver supplied in the tool kit. This gauge has a thickness of .012 in. (0,30 mm.) and if the setting is correct the gauge should be a sliding fit. If the gap varies appreciably from the gauge the contact breaker must be adjusted. To adjust, keep the engine in position to give the maximum opening of the contacts and slacken the two screws which secure the contact plate. Move the plate until the gap is set to the thickness of the gauge and then fully tighten the locking screws.

Fig. 30. Contact breaker

B-Octane selector.
D-Contact breaker pivot.
E-Diaphragm housing.
H-Screws securing contact plate.

The distributor should be thoroughly cleaned at intervals.

Wipe the inside and the outside of the moulded distributor cap with a soft, dry cloth, paying particular attention to the space between the metal electrodes. See that the small carbon brush on the inside of the moulding works freely in its holder.

Fig. 31. Cleaning contacts, with moving contact removed.

Examine the contact breaker. The contacts must be free from grease or oil. If they are burned or blackened, clean them with a fine carborundum stone or with very fine emery cloth. Afterwards wipe away any trace of dirt or metal dust with a petrol-moistened cloth. Cleaning of the contacts is made easier if the contact breaker lever carrying the moving contact is removed. To do this, slacken the nut on the terminal post and lift off the end of the contact breaker spring which is slotted to facilitate removal. The lever can then be lifted off its pivot pin. After cleaning and replacing, check the contact breaker setting.

If the contacts are badly burned, they should be replaced. Replacement contacts must only be fitted in pairs. To remove the moving contact, follow the procedure outlined in the previous paragraph. To remove the plate carrying the fixed contact take out the two screws complete with spring and plain washers. Fit the replacement contacts by reversing these instructions and set the contact breaker gap to .012 in. (0,30 mm.) by means of the gauge supplied in the tool kit.

The high tension cables are those connecting the coil to the distributor and the distributor to the sparking plugs. When these cables show signs of perishing or cracking they must be replaced by 7 mm. rubber-covered ignition cable.

The method of connecting H.T. cable to the coil is to thread the knurled moulded nut over the cable, bare the end of the cable for about 0.25 in. (7 mm.), thread the wire through the washer removed from the end of the original cable and bend back the wire strands. Screw the nut into its terminal.

Fig. 32. Fitting H.T. cable to ignition coil

A-H.T. cable.
C-Cable strands.
D-Moulded terminal.

To connect cables to the distributor, unscrew the pointed fixing screws on the inside of the moulding and push the cables, which should not be bared but cut off flush to the required length, well home into their respective terminals and tighten the fixing screws. The screw securing the centre cable is accessible when the carbon brush is removed.
Fig. 33. Connecting H.T. cable to distributor.

A-Carbon brush.
B-Screws securing cable.
Instructions for replacing most of the bulbs listed here are given in the following pages; in other cases your dealer will be able to help you.


Home models, R.H. headlamp
Home models, L.H. headlamp
R.H.D. Export models
L.H.D. Export models . (Except North American vehicles).
Sidelamps (except North American vehicles).
Sidelamps (North American vehicles)
Stop / tail lamps (except North American vehicles).
Stop! tail lamps (North American vehicles).
Instrument panel lights
Ignition and mixture control Warning lights
Oil pressure and headlamp warning lights
Rear number plate lamp

Lucas No.

No. 162
No. 300
No. 300
No. 301
No. 989
No. 207
No. 353
No. 207
No. 970
No. 987
No. 989





To remove the light unit for bulb replacement, first slacken the securing screw and lift off the rim. Remove the dust-excluding rubber, when three spring-loaded adjustment screws will be visible. Press in the light unit against the tension of the screw springs and turn it in an anti-clockwise direction until the heads of the screws can be disengaged through the slotted holes in the light unit rim. Twist the back shell in an anti-clockwise direction and pull it off; the bulb can then be removed.
Fig. 34. Headlamp bulb replacement.

Fit the replacement bulb in the holder, taking care to locate it correctly and replace the back shell. Position the light unit so that the heads of the adjusting screws protrude through the slotted holes in the flange, press the unit in and turn in a clockwise direction. Replace the dust excluder and front rim.
The headlamps should be set so that the main driving beams are parallel with the road surface. If adjustment is required, remove the rim as described above. The vertical setting may then be made by turning the screw at the top of the lamp and horizontal adjustment can be altered by the screw at each side of the light unit.


SIDE LAMPS (Except North American vehicles).
Slacken the screw at the top of the lamp locating it in the scuttle panel and turn the lamp in a clockwise direction until the tongue at the bottom is disengaged from the scuttle. The lamp front and reflector can then be withdrawn.
The bulb is accessible when the holder which is clipped to the back of the reflector is turned to the left and pulled off.
When refitting the front and reflector, locate the tongue on the lamp in the slot in the scuttle and turn the lamp in an anti-clockwise direction. Finally secure by means of the locating screw.

SIDE LAMPS (North American vehicles only).
The side lamp rim and glass are secured to the lamp body by means of a rubber bead. To gain access to the bulb, lever the rubber ring away from the lamp and remove the glass from the bottom of the lamp. When refitting, move the rubber bead aside, locate the rim at the top of the lamp and press it into position; finally position the rubber ring so that it fits snugly round the lamp rim.

STOP/TAIL LAMPS (Except North American vehicles).
To effect bulb replacement, slacken the securing screw and swing open the cover; the bulbs are then accessible in the lamp body.

STOP/TAIL LAMPS (North American vehicles only).
Bulb replacement is effected in a similar described for the manner to that sidelamps.

REAR NUMBER PLATE LAMP (North American vehicles only).
To effect bulb replacement, slacken the securing screw and swing open the cover; the bulbs are then accessible in the lamp body.


All horns before being passed out of the Works are adjusted to give their best performance and will give a long period of service without any attention; no subsequent adjustment is required.

"If the horn becomes
uncertain in its action"

If the horn fails or becomes uncertain in its action, it does not follow that the horn has broken down. First ascertain that the trouble is not due to some outside source, e.g., a loose connection, short circuit in the wiring of the horn, discharged battery or blown fuse. Lithe fuse has blown, examine the wiring for the fault and then replace the fuse.

It is also possible that the performance of a horn may be upset by the fixing bolt working loose, or by some component near the horn being loose. If after carrying out the above examination the trouble is not rectified, do not attempt to dismantle the horn, but return it to a Lucas Service Depot or Agent.

The reflectors are protected by a transparent and colourless covering which enables any accidental finger marks to be removed with chamois leather or a soft cloth without affecting the surface of the reflector, metal polish must not be used for cleaning reflectors.

To start the wiper, pull out the handle to disengage it from the switch. Then move the switch lever to the left to the "on" position.

To stop the unit, move the switch downwards to the " off position, pull out the handle and turn the end into the top of the switch control.
No adjustment or lubrication is necessary, as the gears are fully lubricated before leaving the Works.

To remove the arm and blade assembly, slacken the fixing nut and tap sharply to release the collet which clamps the arm on to the spindle. Then remove the complete assembly.
When fitting the replacement arm and blade, slacken the securing nut and push the arm fixing brush over the end of the spindle as far as it will go. Secure by tightening the nut.

To fit a new blade only, take out the rubber bush securing the old blade to the arm. Insert the tongue on the replacement blade through the slot in the arm and secure it by fitting the rubber bush through the hole in the tongue.

The ignition switch, besides forming a means of stopping the engine, is provided for the purpose of preventing the battery being discharged by the current flowing through the coil windings when the engine is stopped. A red warning light on the instrument panel appears when the ignition is switched on and the engine is running very slowly or is stationary.
Should the warning lamp bulb burn out, this will not in any way affect the ignition system, but it should be replaced as soon as possible in order to safeguard the battery.

The appearance of the amber mixture control warning light on the instrument panel indicates that the "COLD START" control has been left out inadvertently and must be pushed right in at once.
If the warning lamp bulb burns out, it will not affect the operation of the mixture control, but it should be replaced as soon as possible to ensure that the control is pushed " home " at the earliest possible moment, and so safeguard against unconscious driving with the mixture control in an intermediate position, with consequent high petrol consumption and dilution of the engine oil.

The oil pressure warning light on the instrument panel glows when, for any reason, the engine oil pressure drops below 10 to 12 lb. per sq. in.' (0,7 to 0,8 Kg. /cm2.). It will, therefore, light up when the engine is stationary and will go out when the engine has started and the oil pressure has built up to exceed this figure. Should the warning light appear at any time during normal vehicle operation, the engine must be stopped immediately and the cause ascertained usually it will be due to low oil level in the sump.
Should the warning lamp bulb burn out, it should be replaced as soon as possible to safeguard the engine.