The only brake adjustment necessary between overhauls is that for normal lining wear indicated when pedal travel becomes excessive. The adjustment must be carried out with the drums cold.

1. Release the parking brakes and jack up each rear wheel in turn to adjust.
2. Slide back the adjusting slot cover on the brake back plate. Using a screwdriver, turn the notched adjuster wheel towards the rear of the tractor to expand the brake shoes in the drums, i.e. with the screwdriver engaged in the wheel as shown in Fig. 22 move the handle of the screwdriver towards the front of the tractor. Continue until the shoes are fully expanded.

Fig. 24 - Wheel bearing adjustment

Tyres have the all important job of converting engine power into traction. Correct tyre maintenance is essential from the point of view of efficiency in work and also because it will help prolong tyre life. The most important aspect is that of tyre pressures. The correct pressures are given in the specifications at the end of this manual and these should be checked weekly using an accurate gauge. If the tyres are waterballasted obtain a special water gauge which is corrosion resistant.

Fig. 25 - Detaching tyre from rim

Always replace the valve caps tightly; they act as a second air seal and also keep dirt out of the valve cores. Under-inflation will reduce tyre life by allowing excessive flexing of the tyre walls. Do not reduce pressures excessively to obtain improved wheel grip; adding wheel weights or liquid ballasting is more effective and will not impair tyre life. Over-inflation will impose heavy stresses on the tyre walls especially on hard stony ground, and will reduce wheel grip.

CAUTION: Care should be taken to ensure that the soft rubber lip on the inner edge of the tyre bead is not damaged by the tyre levers as such damage will subsequently tend to chafe the inner tube.

Fig. 27 - Replacing tyre on rim

It should be borne in mind that when installed on the tractor the "V" of the tread should always point forwards (viewed from above) and also that the offset lugs on the wheel rims should be symmetrically positioned facing inwards or outwards depending on the track setting. The wheel assemblies are therefore a pair and it is possible, unless due care is taken, to fit a tyre incorrectly on its rim.

Liquid ballast may be used to provide an alternative or an addition to wheel weights. If there is anv possibility of frost, calcium chloride should be added to the water to act as an anti-freeze otherwise ice may form inside the tube, become broken up when the tractor is used and cut the tube. When this solution is used 1 lb. of lime should be added to every 100 lb. of calcium chloride to prevent acidity.

CAUTION: Never mix the solution in the tyre; put the calcium chloride in water (NOT THE WATER ON CALCIUM CHLORIDE) in an open container and allow to cool.

Radiator anti-freeze must not be used in tyres or calcium chloride used in the radiator.

To obtain 100 per cent water ballast a special pump is necessary. It is however possible to fill 90 per cent of the tyre as described below using either a stirrup pump or a tank 6 to 8 ft. (2 meters) above the tyre, in conjunction with a special adapter obtainable from your authorised Dealer.

TO WATER BALLAST A REAR TYRE:

1. Jack up the wheel of the tractor and chock the wheel with the valve in its lowest position.
2. Secure the tyre valve to prevent it slipping inside the rim and then unscrew and remove the valve core.
3. Screw the adaptor onto the valve so that the plastic tube enters into the crown of the tyre.
4. Feed in the solution and as the tyre fills, slowly turn the wheel (to allow the air to escape) until the valve is at the top.
5. When the solution issues from the small pipe in the side of the adaptor in a steady stream, the solution has reached the correct level.
6. Remove the adaptor and replace the valve core.
7. Remove the jack and adjust the tyre pressure to 12 lb. per square inch with the valve at the top of the wheel.

The above table is correct for a solution of 2 lb. of commercial calcium chloride per gallon of water (0,2 kg per litre) which will protect the tyre against freezing down to a temperature of 18 oF (-8 oC), 4 lb. per gallon of water will give protection to -8 oF (-22 oC.) and 6 lb. per gallon to -44 oF (-42 oC).

The cast figures on the outer axle beams indicate the track width when both outer axle beams are symmetrically positioned (Fig. 28). Figures marked on the top of the flange of the outer axles indicate the track width when they line up with the innermost hole (Hole A) of the centre beam. Similarly the figures on the bottom flange indicate track width when lined up with the outermost hole (Hole B) of the centre beam.

There is provision for altering the rear wheel track between 48 and 76 in. in stages of 4 in. for rowcrop work. There are three separate methods of mounting the rear wheels and the full adjustment range of 28 in. is obtained by using various combinations of these three methods.

Firstly, each wheel disc is heavily dished and the track may be altered 16 in. by reversing the discs to face inwards or outwards on the hubs as required.

Secondly, the method of securing each wheel rim to its disc is by bolting to six lugs welded to the rim. A decrease in track of 4 in. is obtained by repositioning the rim jugs from the inside to the outside of the discs and vice versa.

Thirdly, the lugs being off-set from the centre of the rim, a track alteration of 8 in. is available by interchanging the right and left hand rims.

The complete range of adjustment is shown in Fig. 30. One wheel only is shown in this diagram, and it should be remembered that both wheels should always be reset to corresponding positions to obtain these settings. It will be seen that in four cases it is possible to reset the track simply by interchanging wheel assemblies. Always ensure that the wheels are fitted correctly with the "V" on the tyre tread pointing forwards at the top otherwise wheel grip will be affected. The wheel nuts should also be checked for tightness after a few working hours.

Power adjusted rear wheels are available as an optional extra and provide a rapid means of adjusting the rear track between 48 in. and 76 in. Engine power is used to alter the wheel settings and an adjustment range of 48 in. to 64 in. is obtainable with the wheel discs mounted on the rear hubs in the standard position i.e. dished inward from centre to rim. A further adjustment range of 60 in. to 76 in. may be obtained by interchanging wheel assemblies. Changing the track with a power adjusted wheel is similar to turning a bolt in a nut. The rim acts as the nut, with slotted channel bars which serve as threads. The wheel disc acts as a bolt having a helical shape with a 2 in. pitch. The different track widths available are shown in Fig. 31 and it will be seen that one complete revolution of each wheel makes a 2 in. alteration in the track. Both rear wheels should be adjusted to symmetric positions to obtain the settings indicated, but by placing the spacer clamp in other channels on the rim, spacings at half inch intervals can be made. It is not necessary to jack up the wheels clear of the ground and once the the desired setting has been determined each wheel should be adjusted separately as follows:

1. LOOSENING THE RIM FROM THE WHEEL
   • Remove the large nut on the spacer clamp, turn the spring loaded locating stud through 90 degrees and remove the clamp from the wheel.
   • Loosen the nut on each of the three rectangular locking clamps, slide the clamps towards the hub of the wheel and tighten the nuts to hold the clamps in position.
2. MOVING THE WHEEL DISC IN THE RIM
   NOTE: to increase the track (i.e. to move the wheels outwards) use low reverse gear for the left wheel and low forward gear for the right wheel. To decrease the track use low reverse gear for the right wheel and low forward gear for the left wheel.
   • The final track adjustment must always be made inward (providing the wheels are not reversed). If an increase in track is required it will be necessary to move the disc beyond the desired setting and then move it back onto the setting. Therefore with the engine at idling speed move the tire outward by engaging the clutch with the tractor in the correct gear and at the same time holding the opposite wheel with the brake so that the tractor rolls slowly. Disengage the clutch immediately when the wheel disc strikes the end stop. If it is required to move the wheel inward to decrease the track it is not necessary to move the disc back on to its stop before proceeding with the adjustment.
   • Place the spacer clamp in the channel thread bar for the desired settings as shown in Fig. 31. The oval foot of the spring loaded locating stud is inserted in the channel slot, then turned so that the bolt head is secured in the channel.

     
     Fig. 31 - Selecting the track width

   • Move the wheel inward by selecting the correct gear, engaging the clutch with the engine at idling speed, braking the opposite wheel to let the tractor creep while the wheel disc is revolving. Disengage the clutch immediately when the wheel disc strikes the spacer clamp, see Fig. 32.

     
     Fig. 32 - Wheel disc against spacer clamp

3. SECURING THE RIM IN POSMON
   • Remove the spacer clamp from the channel bar by turning the spring loaded locating stud through 90 degrees.
   • Use the spacer clamp as the fourth wheel locking clamp. Replace the clamp on its stud, locating the lug in the holding slot and engaging the spring loaded locating stud through the wheel disc. Install the large nut and washer and tighten the nut securely. The spacer clamp used as a driver clamp is shown in Fig. 33.

     
     Fig. 33 - Spacer clamp used as a driver clamp

   • Loosen the nuts on the three rectangular locking clamps and move them into the clamping position in the thread channel. Tighten all clamp nuts securely.
     NOTE:The clamp nuts should be tightened again after the tractor has been used for a short period.
4. CHANGING THE WHEEL DISCS
   When a track greater than 64 in. is required wheel spacings of 68, 72 or 76 in. can be obtained by setting the track at 48 in. for a 76 in. track, 52 in. for a 72 in. track and 56 in. for a 68 in. track then reversing the wheels on the tractor.
   • Loosen the eight nuts on the wheel studs at each rear hub.
   • Raise the rear of the tractor and be sure it is firmly supported.
   • Remove the nuts and interchange the wheels so that they dish outward from centre to rim. The arrow on the side wall of the tyre should always point in the direction of forward rotation of the wheel.
   • Replace the wheel nuts, lower the tractor and tighten the nuts securely.
     NOTE: with the wheels reversed (dished outward) it will be necessary to set the spacer clamp and locking clamps from the inside of each wheel when making adjustments. Disengage the spacer and locking clamps, move the tyre to its extreme "in" position and set the spacer clamp as desired. Use the tractor power to adjust the wheel to the desired width and, after adjusting, replace the spacer clamp and locking clamps and tighten them securely.

Fig. 34 - Topping up the battery

Distilled water only must be used for topping up and it should be stored in clean covered containers made of glass, china, or rubber. If the electrolyte level requires topping up at frequent intervals this may indicate that the charging rate is too high and the regulator should be checked for correct operation.This work should not be undertaken by unskilled personnel as it requires special equipment to achieve the correct setting of the regulator. The battery electrolyte has a low freezing point and the battery will not suffer damage in cold weather unless it is allowed to become discharged. The electrolyte will then freeze at an appreciably higher temperature. For the same reason in cold weather topping up should only be done during charging and preferably when the cells are gassing freely so that the water becomes mixed with the electrolyte and does not freeze. If electrolyte is spilled on the battery top, clean with a rag moistened with ammonia.

When fitting a battery to a tractor always connect the positive terminal to the earth strap. Keep the battery top clean and the connections tight and protect the terminals from corrosion by coating them with petroleum jelly. If the tractor is to be "laid up" for the winter the battery must be correctly prepared for storage or it will deteriorate. This work is best undertaken by your authorised dealer and should not be entrusted to inexperienced hands.

An indication of the battery state of charge may be obtained by checking the battery specific gravity using a hydrometer. From the following table it will be seen that the specific gravity reading drops as the battery becomes discharged. It should be noted that batteries supplied for use in tropical climates are initially filled with a lower specific gravity, as indicated in the right hand column.

Regular servicing will go a long way to eliminate irksome time-wasting troubles. If however there comes a time when you have difficulty when starting the engine, or if the engine does run but does not run correctly, then the charts on the following pages will enable you to approach the problem systematically.

Fault finding chart - Engine will not start (click to enlarge)

Fault finding chart - mechanical (click to enlarge)