This checklist can save you from a lot of grief when buying a used tractor
The escalating cost of a new tractor has forced many farmers into considering the purchase of a used tractor. But the road to a successful purchase is fraught with danger. The overriding principle in making such a purchase, is the old Roman dictum, caveat emptor – let the buyer beware. The onus is on the buyer to ensure that the used tractor he purchases is free from hidden problems. This means that the farmer must examine his needs, the seller and the used tractor carefully before committing to the purchase.
Assess the needs
Before the farmer even begins looking at used tractor models, he should know what he is looking for. He should carefully examine his needs, so that the model he buys will be able to function as required, both in terms of tasks and power output. He should also determine whether he can afford the model he is considering, not only regarding purchase price, but also maintenance.
Assess the seller
The next element in the purchasing chain is the seller, and here the farmer has a number of options. He may buy from a reputable dealer, or from a trusted friend. He may buy from some other farmer, or at an auction. However, he should always remember, caveat emptor. If the farmer is inexperienced, the first option is probably the better one. The dealer may even give him some form of guarantee, as well as pre- and after-sales service. Also, a friend is not likely to lie about the history of the tractor.
Assess the tractor
And that is where the farmer should begin his assessment of the tractor – with its history. Start with the tractor’s age, model and hours worked. Ensure that the claimed hours tally with the overall appearance of the tractor and the work that it has been doing. Is the tractor sufficiently reliable and affordable considering the expected costs of repairs and maintenance? What follows is a checklist the farmer may use in evaluating whether a tractor is worth the money and possible trouble involved.
Overall visual impressions
The first clues to the worth of a tractor lie in the visual appearance. Does the machine look as if it has been cared for? Here the farmer should look for signs that the tractor is going to need repair, or has been repaired, but in a sloppy manner. Makeshift repairs often indicate that the previous owner did not care for the machine. Perished rubber or plastic components, as well as faded paintwork may indicate that the machine was stored outside.
Take advantage of your sense of touch. Lubricants collect dirt and metal chips and retain them, making it easy to detect extreme neglect. Evidence of grease in an area does not necessarily mean that the tractor has been properly cared for. Remove the grease fitting and examine the interior. The grease should be shiny, tacky and clean. If the grease well looks dry, or the grease is lumpy, the unit has not been greased properly. If a component is loose and can be wiggled, excessive wear has taken place.
Seals and bearings
While on the topic of grease, check the seals and bearings. A collar of grease on the wheel bearing will indicate either a failing wheel bearing, or one that needs to be properly seated by tightening the spindle nut. The collar is formed by lateral movement of the hub, which ploughs excess grease into a ring or collar. Usually, these collars mean bearing assemblies and seals need to be replaced because the lateral shifting has introduced dirt, grit and water past the seal into the bearing. A simple test to determine whether the wheel bearings are not properly seated, or are worn, is to bump the tyre with your knee. Even the slightest clunk indicates that there is a possible problem.
Examine the engine
A bad front or rear main bearing can cause a loss of oil and gives an idea of the age of the vehicle. Look for oil spots on the ground near machinery. Also look under the tractor, both in front of, and behind, the oil pan. Scattered fresh oil will indicate that the seals are probably worn out. Coincidentally, if the seals are worn, then the crankshaft bearings may also be worn, because they, too, have been in the engine since it was bought. Replacement of seals and bearings may be expensive.
If the tractor is water-cooled, examine the radiator fill area while the engine is cold, as this will provide a number of clues to the engine, not just the radiator. A creamy white deposit on the underside of the cap indicates that exhaust gases may be leaking into the coolant system. This could be caused by a leak in either the cylinder head gasket or water jacket.
Discoloured or flaking paint around the cap may indicate that the engine was overheated. Possible causes of this could be a lack of coolant, or that the thermostat or radiator has become plugged, or that there is a collapsed hose, a faulty water pump, or a major head gasket leak.
Look inside the radiator for signs of corrosion. Severe corrosion means that the radiator may need to be replaced. Also examine the outside of the radiator for damaged fins or signs of repairs. Stains along the fins usually indicate a leak. Squeeze the radiator hoses to see if they are cracked and brittle.
A healthy engine will have a negligible amount of water in its oil. Examine the dipstick. In both petrol and diesel engines, creamy white droplets or accumulations near the top of the dipstick indicate an oil-water emulsion. This water may have come from a leaking coolant system, outside storage, or vapour from fuel accumulating in the oil sump. Also, check the breather tube outlet for caked oil or an obvious flow of exhaust gases, which signal that the piston rings may be worn.
If the occasion allows, take small samples of both the hydraulic and engine oil by tapping off the bottom of the reservoir. It is a messy operation, but it does allow you to check for water, which will flow out first. A few drops of water may be tolerated and is no cause for alarm. However, a thick gooey sludge is an indicator of poor maintenance. If metal chips are present, or the oil has a silver grey sheen, move onto the next machine or sale.
Brakes and clutches
Depress the left and right brakes independently. If the movement is not similar, the brakes may need some attention. Run the engine at a high idle with both brakes locked together and the transmission in a mid-range gear. Gently further out the clutch while depressing the brakes. This will check the clutch, the brakes and the responsiveness of the engine governor. The governor should gently increase the engine speed as the engine struggles to move the tractor forward. You should be able to stall, or nearly stall the engine with the brakes.
Check whether the clutch engagement is smooth and positive, or whether it seems to slip. Slippage indicates that adjustment or repair may be necessary. If the machine pulls left of right, the brakes may be poorly adjusted or faulty. If the tractor has a mechanical clutch which is not hydraulically assisted, a pending clutch problem may sometimes be detected by manually disengaging the clutch pedal.
With the brakes set, the transmission in neutral and the engine running, slowly depress the clutch and feel for smooth movement in the linkage. Once the pedal is down, listen and feel for a noisy, rough clutch release (throw out) bearing.
If you feel vibrations, or the clutch pedal movement is rough, there is a good chance that the clutch may need to be overhauled. Although replacing the release bearing may seem a simple enough task, it often entails splitting the tractor, and once you have gone that far, it is best to replace the clutch disc, pressure plates, etc. In short, it could cost you more than the tractor is worth.
Engine and battery
Check how easily the engine starts. If it starts easily, the battery is probably in good condition. Let the engine idle and listen to the tone of the engine. The engine should run evenly without any rumbling or knocking sounds. Check the paintwork around the head gasket of the tractor to see if it is the original paint. If oil and dirt streaks have been altered, typically above the head gasket, the cylinder head gasket may have been replaced recently.
While a new gasket may not be indicative of major problems with the engine, you should ask the seller why the cylinder head was removed. Some owners remove heads but unknowingly re-use the old gasket. Be wary if marks show a head removal, but the gasket edges are old and stained.
Hydraulic couplers that are capped and clean are a good sign. If the couplers are capped, removal of the caps should reveal shiny metal and droplets of clean hydraulic oil. Uncapped, dirty couplers are often a clue to the fact that dirt or water may have entered the system, while rusty retainer balls indicate that couplers have been exposed to the weather.
The hydraulic control valves, also called spool valves, should be inspected to get an idea of how much use they have endured. Control levers which flop around and have poorly defined strokes have had plenty of use. Worn pivot pins are an indication that a valve has seen many cycles.
Fully extend the spools and check for longitudinal score marks, wiggle them a bit to see if hydraulic oil seeps out. If it is possible, run the engine, bring the hydraulic system up to operating pressure and check for leaks. A valve under pressure should be capable of slowly and surely directing pressurised fluid to do work. If motors or cylinders chatter or operate erratically, internal valve problems may exist.
Very few of the older used tractors are supplied with external hydraulics. The following simple tests may be done to evaluate the hydraulic system:
- Hitch a fairly heavy implement, lift it up and switch the tractor off. The implement should stay in the up position.
- Operate the lift a couple of times. The implement should go up and down smoothly.
- Change the speed of the hydraulic system from fast to slow and see if there is any response.
In dry air filtration systems, remove the filter element from the canister and look for a dusty spot along the flexible gasket where the elements may have been bent or not properly seated in the canister. This would mean that dust has found a path of least resistance, has passed the element and flowed into the engine, causing unnecessary wear. Crumpled filter elements also seal poorly and may be fractured, causing gaps between the pleats and the end caps.
Dust unloader valves collect and store dirt which settles from dry air filter elements. If the rubber is dried, cracked or torn, a vacuum created by the engine can suck air and dirt into the flawed valve, bypassing the designed dirty air flow path into the filtration system. Excessive dirt then collects in localised areas of the filter, causing restrictions and plugged elements.
If the tractor has power steering, rock the steering wheel left and right while the engine is running. The front wheel should begin to move smoothly without any squeals from the relief valves. Rough movement of the wheels may indicate bent hydraulic cylinder rods, worn or seized knuckle joints, due to a lack of lubrication, or too little hydraulic fluid.
With manual steering, a hand movement more than a few centimetres left or right, before the front wheels start to move, may indicate worn steering gears (backlash), or worn pivot joints in the linkage.
Check the gearbox for lubricant leaks around the output shaft seals. Restricted steering wheel movement may indicate bent or twisted linkages or control arms, or poorly lubricated, binding joints.
If the engine can be run, examine the exhaust smoke. At constant engine speed, black smoke may mean improper fuel, a faulty fuel injection system, incorrect engine timing, or a badly adjusted carburettor. White smoke at a constant engine speed could be due to a low engine temperature because the tractor was not warmed up or has a faulty thermostat, incorrect engine timing, or a coolant leak into the engine combustion chamber.
Even experts are fooled by exhaust smoke systems. Generally, continuous black smoke in diesels is an injection-related problem. If white smoke persists, allow the radiator to cool and remove the radiator cap. Then, while the engine is running again, check for gas bubbles in the radiator which would be indicative of a coolant leak.
Blue smoke comes mainly from an excess of lubricating oil in the combustion chamber, resulting from deterioration of piston ring sealing or valve guide wear, indicating the need for a mechanical overhaul.
Use this checklist as a guide in examining a used tractor, and you will reduce the risks involved with the purchase. Remember, caveat emptor. Ensure that the used tractor will give you value for money before you sign on the dotted line.