Critical to any tractor purchase is the initial assessment. Start with its history, many tractors record the hours worked. Do they tally with its appearance? Is the clutch pedal worn? Does the machine look cared for? Are there signs the tractor is going to need repair or has been repaired – haphazard and sloppy repairs generally mean the previous owner did not look after the machine. Faded paintwork, perished rubber or cracked plastic fittings often indicate that the tractor was kept outside for its working life.

Before starting the engine unscrew the radiator cap a creamy white mess on its underside can indicate that exhaust gases are leaking into the cooling system. Look for signs of corrosion inside the radiator and for signs of repairs to the outside, made sure the radiator hoses are not brittle or split.

Start the tractor from cold, if it starts easily the battery is probably in good condition. Let the engine idle, does it run evenly without rumbling or knocking sounds. Look at the paint around the head gasket – is it original or has it been disturbed, if it is flaking above the head gasket the cylinder head gasket may have been recently replaced. A new gasket may indicate major engine problems, but try to find out why the cylinder head was removed. Be cautious if marks show a head removal but gasket edges are old and discoloured. Inspect the block for hairline cracks or signs of welding, is it the original engine, as collectors of classic tractors we have often raced to see a rare tractor only to find the original engine has been replaced with some vile lump of iron.

Check the body work and if re-sprayed was it to enhance the tractor or to cover poor bodywork. If the tractor has a cab make sure it is not rusted on the door sills. Many tractors had front end loaders fitted early in life, look for signs on the chassis frame, there will be marks where one was bolted on to it, loader tractors often have had their fronts damaged, the damage may look superficial but check that tractors, such as Nuffield’s, with the fuel tank fitted to the front have not had the tank distorted by a front end loader shunt. Over enthusiastic use of loaders can damage the clutch and lead to wear in the front axle. n Look where the tractor is standing, if there is a brown coloured deposit on the ground it is usually due to oil leakage, where is it in relation to the machine, if it is dark brown, feels thick and is under the oil pan it tends to come from the engine, look on the engine block is the line it has travelled down visible can it be traced back to something like the valve cover, if the oil is blackish/brown it needs changing and indicates neglect.

Check for leaks with the engine running, but stand clear, I was the victim of a pressurised leak spurting oil at me when I stood too close to a tractor’s engine at an auction. Most old tractors have some dusty oil film around hose connections but anything obviously seeping out will need attention.

Whitish coloured oil on the ground indicates water contamination, several factors cause this: the tractor not having been ran for long enough to warm up property causing condensation, leaking coolant, even a lack of weather protection, an old pan or kettle covering an open exhaust stack helps prevent water problems. An oil change and allowing the tractor to warm up properly often remedy this problem but if the engine has been running and definitely has water in the oil or it is foaming, unless you want a restoration project walk away.

Yellow fluid is usually caused by battery acid seeping out and corroding down the housing, often cured by a new battery. Green or blue puddles underneath are often antifreeze, due to a badly fitted or worn radiator cap or the core of the radiator being rotten, in which case the radiator will need either reconditioning or replacing. Check all the radiator hoses if they are brittle they will need renewing which is a relatively inexpensive operation.

n After the bodily fluids look at the exhaust smoke, white or black indicates an ignition or carburetion fault, sometimes because the timing is out. White smoke that the tractor is not properly warmed up or has a faulty thermostat, blue smoke is generally caused by excess lubricating oil in the combustion chamber and can indicate serious problems with pistons, rings or valve guides. n Also listen to the engine a gently ticking noise from the top often means a valve needs adjusting. While a deep thumping sound from the bottom or middle that is more pronounced under load usually indicates a serious and generally expensive problem.

Check the steering, with manual steering any movement of more than an inch or two to the left or right before the front wheels start to move points to excessive wear to the steering gears or pivot joints in the linkage. If the tractor has power steering the front wheel should begin to move smoothly when you rock the steering wheel from left to right with the engine running, jerky movements suggest worn or seized knuckle joints, bent hydraulic cylinder rods, poor lubrication or a lack of hydraulic fluid.

n Test the brakes, your life may depend on them, if the clutch is rough or vibrates it may need overhauling or replacing, many tractors need to be split to work on the clutch and replacing the clutch and the clutch disc, pressures plates and so on without the facilities or knowledge to do it yourself is a very costly enterprise, so if you suspect a serious clutch problem don’t just walk run away.

n If the tractor has hydraulics test them, preferably under load, at the very least raise the lift arms a few times. Engage the power take off (PTO) check it runs smoothly, if it wiggles from side to side there is usually a fault somewhere. The PTO is a potentially dangerous feature on all tractors and is particularly hazardous on older tractors which often lack shields, starter lockouts and other more modern safety features, it is easy to get clothing caught on them so afford a PTO the respect you would a chain saw.

Check the tyres, do they suit your needs, grassland tyres are pointless if you want to go ploughing, is there plenty of wear still left in them, replacing tractor tyres is expensive so check much a set of new types can add to the purchase price.

If the object of the exercise is to find a restoration project different criteria apply, restoring a tractor is a hungry pastime eating time and money and although it may prove personally rewarding painstakingly restoring a very common make of tractor can leave you with a machine worth less than it cost to get the work done. It is always advisable to check out what well restored models fetch on the open market before starting your own restoration as well as costing the work before starting. n Buying a rare tractor may appeal to the enthusiast but for regular use will have its own set of problems, many tractors are “rare” because they were no good in the first place so demand was low and they were quickly replaced by a better model. Parts are difficult if not impossible to find and may need to be machined which, although there are specialist restorers, can prove to be very expensive.

Happily there are numerous agricultural engineers in rural areas who are more than capable of keeping an older tractor running and many agricultural colleges offer short “tractor maintenance” courses which benefit the new tractor owner.

Finally don’t forget whilst agricultural tractors do not pay a licence fee they will need to be insured, registered and issued with a tax disk in order to be driven legally on the public highway. In addition whilst tractors driven on the road do not need an MOT type of inspection they must be in a road worthy condition, brakes working, no bald tyres, adequate lights as do trailers used for road work. Common sense really.